Improvements in Systems of Electric Distribution.
Year: 1893

page_text: Date of Application, 17th Oct., 1893
Complete Specification Left, 9th July, 1894-Accepted, 14th Aug., 1894
PROVISIONAL SPECIFICATION.
Improvements in Systems of Electric Distribution.
I, CHARLES ARTHUR ALLISON, of 52 Chancery Lane, London, in the County
of Middlesex, Patent Agent, do hereby declare the nature of this invention (v
(which
has been communicated to me from abroad by Cyprien Odillon Mailloux, of the
City, County and State of New York, U.S.A., Electrician and William S. Barstow,
of Brooklyn, County of Kings and State of New York, U.S.A., Electrician), to be
as follows:-
This invention relates to those systems of electric distribution known as constant
potential systems, so called because the potential difference in the consumption
circuits or mains is maintained constant independently of the load which they carry
or their distance from the source of supply or generating station. It is customary
in practice to maintain these consumption circuits of the required value and con-
stancy of potential difference by means of so called feeder circuits conveying
electrical energy from the generating station and delivering it to the mains at
various points. Inasmuch as these feeder circuits are not all of equal lengths or
do not carry equal loads, it is found necessary to so proportion their conductivity,
by varying their sectional area, that the loss or drop of potential at full normal
load, will be equal or nearly so in all the feeders. It is found, however, that all
the feeders are not necessarily fully loaded or unloaded at the same time owing to
the location of the mains they supply. Thus, for example, in wholesale and office
districts the greatest load is carried on the feeders in the day time while in
residence districts, the greatest load is reached in the evening. Under such con-
ditions the potential of the generators at the station cannot be raised to suit the
loaded feeders, without becoming excessive for the feeders supplying mains which
are only partially loaded. For this reason it has been found almost indispensable
to interpose variable artificial resistance or "feeder equalizers "in the feeder
circuits whereby the drop or fall of the potential in the partly loaded feeders is
artificially increased and regulated so as to maintain a constant potential at the
mains. It is obvious that the energy consumed in heating this artificial resistance
is wasted.
The principal object of the present invention is to obviate any loss of electrical
energy in the feeders, beyond the intrinsic loss due to their own resistance.
Another object of the invention is to provide means whereby different potentials
can be successfully employed in the supply or generating station to suit the varying
conditions of loss or drop in the feeders due to their distance and the load they
carry, and to provide means whereby the feeders can be readily and expeditiously
transferred from one potential to a higher or lower one without affecting the rest
of the system or without interrupting or disturbing the service at the mains
supplied by said feeders.
The present invention consists broadly in the use of distinct graded potentials,
however, produced, for the several feeder circuits or sets of circuits; each potential
being adapted to a different condition of feeder load or length, with suitable feeders
for shifting the feeders from one potential to another as occasion may require, in
combination with a potential regulator which may be either a source of regulable
electro-motive force or a rheostat adapted to be connected and disconnected from
the feeder terminals and employed to artificially and temporarily vary the potential
of a feeder terminal as an accessory step to the switching operation.

page_text: The different graded potentials may be produced either by distinct machines or
banks of machines supplying different bus-bars; or they are derived from the same
initial potential by employing supplemental electro-motive forces to raise or lower
the initial potential, or the two ways may be combined, and one of the features of
this invention consists in such combination.
The invention consists also in the improved combination of apparatus for
supplying the different graded potentials, according to the load at the station, and
consists in the combination with the several bus-bars of graded potential, of
supplemental electro-motive force generators operating in connection with a source
or sources of uniform initial potential for the purpose of raising or lowering the
said initial potential so as to produce said graded potentials, and main generators of
different adjustable or primary potential capacity which may be used alone to
supply the graded potentials to the bus-bars directly when the station load may
make such use an economical one.
The invention consists further in a means for switching the feeder from a source
of one potential to a source of different potential by artificially bringing the
terminal of said feeder to the potential of the source to which it is to be shifted
.and then shifting to such source.
The invention consists further in the special combinations of apparatus as
hereinafter more particularly described and then specified in the claims.
In carrying out the invention any source of regulable electro-motive force or
any variable resistance may be used in the switching operation for the purpose of
artificially changing the potential of the feeder terminal, as hereinafter described,
and in conjunction with such potential regulators suitable switch devices whereby
the said source may be connected to the feeders and disconnected therefrom at
pleasure.
In using a source of electro-motive force as a regulator, it is preferable to
employ for the regulable electro-motive force generator an armature which is used
to vary the potential derived from the main generator or portion of the generator
system by attachment to a bus-bar or otherwise. This supplemental electro-motive
force generator may, by suitable appliances, be employed to either aid or oppose
the potential of the bus-bar to which it is attached so that by connecting it for
example to a bus-bar of an intermediate potential, it may serve to either raise said
intermediate potential to the highest of the graded potentials or to cut it down to
the lowest.
The switch system employed will for convenience be treated as comprising two
parts, one of which I denominate the feeder switch whereby the feeder may be
connected to the different graded potentials, while the other part I denominate
the "booster switch as it serves to connect the supplemental generator to the
feeders.
"
This supplemental generator is herein shown as consisting of an electro-dynamic
armature whose power is regulated by any suitable means known in the art, and
which may be revolved by any suitable motive power.
In connection with the apparatus I use suitable measuring instruments, whereby
the potential at the terminal of the booster switch where it is connected to the
feeder, may be compared with the feeder terminal before connection is made
between the booster and the feeder terminal. I also propose to use suitable means
for comparing the potential of a feeder terminal as modified by the booster with
the potential of the bus-bar switch terminal to which the feeder is to be
tranferred.
One feature of the invention consists in the combination with the feeders and
the boosters, of a suitable differential measuring instrument, and suitable switch
devices whereby two sides thereof may be connected respectively to a booster
terminal and to a feeder terminal of any of the feeders.
When in the operation of the central station it becomes desirable to change the
feeder from a bus-bar of one potential to the bus-bar of another, it is obvious that

page_text: if the feeder terininal be at a different potential from that terminal of the switch
which connects with the bus-bar to which the feeder is to be transferred, there will
be a tendency to sparking on transfer and an interruption or else a disturbance of
the load carried on the feeder and of the general operation of the station; but if
the transfer can be made with a condition of potentials such that the feeder
terminal shall have a potential the same as the source to which it is to be shifted,
then the switching may take place without disturbance.
In the operation of switching the regulable source is used in the following
manner-when a feeder is to be transferred from one bus-bar to the other :-If at
the time a change is to be made, the potential of the feeder terminal be the same
as the potential of the bus-bar to which the supplemental generator is connected
and said generator be not running, it will be obvious that the free terminal pole of
said supplemental generator can be at the same time connected with such feeder
by the switch. In this condition it will be obvious that the feeder will receive
current through the two paths, one through the feeder switch, the other through
the supplemental generator and a booster switch; and under such conditions the
feeder switch may be opened to disconnect the feeder from the source of potential
from which it is to be transferred without disturbing either the load carried on
said feeder or the operation of the station.
The supplemental machine or booster may be now run and its electro-motive
force caused to gradually vary in one direction or the other according to whether
it is necessary to raise or lower the potential of the feeder terminal in order to
bring the potential of said feeder terminal to that of the bus-bar to which it is
desired to transfer said feeder. When this point has been reached, it is obvious
that in like manner the feeder may be switched to the different potential, after
which the supplemental generator may be disconnected leaving the feeder connected
with the desired bus-bar.
If when the transfer is to be made the feeder be at a different potential from
the free terminal of the supplemental armature or regulable generator, the
electro-motive force of the latter will be varied to add to or subtract from the
potential so as to bring the potential of the booster switch terminal to that of
the feeder terminal. The booster switch can then be closed as before upon the feeder
terminal as before described, after which the regulable generator of electro-motive
force can be varied to bring the feeder terminal potential up or down to the
potential of the bus-bar to which it is to be transferred, and the operation
completed as before.
Before connecting the feeder to the booster switch, the potentials of the feeder
terminal and the booster terminal should be compared; for which purpose suitable
electrical measuring instruments may be provided. This comparison I prefer to
make through the operation of a differential measuring instrument, the pointer of
which by standing at zero indicates identity of potential at the feeder terminal
and at the terminal of the booster switch. The same comparison may be made in
the same way between the potential of the feeder terminal and the booster
switch while connected together and the potential of the switch terminal of the
bus-bar or potential source to which the transfer is to be made.
Briefly speaking the plan of operation in switching a feeder from the source of
one potential to another according to this invention, involves firstly, connecting
said feeder to a regulable source whose potential at the feeder terminal is by
suitable means made the same as that of the source from which it is to be
transferred, then disconnecting the latter source and gradually varying the regulable
source until the potential of the feeder terminal is changed to that of the source
to which it is to be shifted, then switching to the latter and finally removing the
regulable source.
In this way it is possible to transfer a loaded feeder from one source of energy
to another, of a different potential greater or less without interfering with the load
and without sparking or other objectionable effect at the switch.

page_text: Other features and combinations forming this invention will be specified in the
claims at the end of this description.
In the accompanying drawings
Fig. 1, is a diagram of an apparatus by which the invention may be practised,
showing the potential regulator consisting of a source of regulable electro-motive
force.
Fig. 2, is a diagram illustrating that part of the invention which relates to com-
binations of main generators and auxiliary generators for providing the desired
bus-bar potentials under different conditions of station working.
Fig. 3, is a diagram of an apparatus by which the invention may be practised,
showing the potential regulator consisting of a rheostat.
Fig. 4, is a diagram of a simplified apparatus.
Fig. 5, is a diagram of a further modification.
Fig. 6, is an enlarged detail plan of a form of switch apparatus that may be
employed.
In the diagram Fig. 1, the invention is shown as applied to a three wire system,
each side of which is shown as practically a duplicate of the other in respect to
switch contacts, measuring instruments, bus-bars, supplemental variable generators,
etc., but as will be readily understood by electricians the invention may be applied
to other systems as, for instance, to four or five wire systems, or to systems in
which no neutral or third wire is employed. A description of the operation with
reference to one side of the three wire system will be sufficient.
A, A', are positive and negative bus-bars, and A2, the neutral bus-bar of a three
wire system, and from terminals of any desired potential fed from suitable
generators as well understood in the art. The potential assumed in the present
case is 115 volts, but might be greater or less. The main source of such potential
is here indicated as consisting of dynamo generators B, B, or banks of generators
with the usual accompaniment of field regulators a, a, for adjusting the potential;
switches b, b, between the dynamos and the bus-bars, voltmeters, galvanometers,
and fuses, etc. Any number of generators may be used suitably connected as
shown, and suitable switches may be provided for connecting and disconnecting
them from the bus-bars A, A1, A2, or from the other bus-bars of the systems.
Said main generators are preferably provided of different regulable or primary
potential capacity so that by suitable connection of them to the bus-bars A, A', A³,
and the remaining bus-bars, as will be fully hereinafter described, different or
graded potentials may be furnished at the bus-bar board direct without the inter-
vention of the supplemental or auxiliary electro-motive force generators to be
presently described; and said main generators may be coupled singly or in multiple
to the bus-bars.
A³, A, indicate auxiliary bus-bars of a lower potential say 110 volts, and A³, Aº,
auxiliary bus-bars of a higher potential, say 120 volts, secured by the intervention
of the supplemental or auxiliary electro-motive force generators C, C1, C2, C³,
applied to raise or lower the potential of the main source to the desired amount
and which are of comparatively small capacity. For this purpose some may be
run as motors to develop counter electro-motive force, and others as generators to
positively supplement the potential; their armatures may be connected as shown
between the bus-bars A, A', of standard or intermediate potential, and the auxiliary
bus-bars of higher and lower potential. Thus the armatures of C, and C³, run as
assisting generators, are connected between A, A', the 115 volt bus-bars and the
120 volt bus-bars so as to raise the potential, while C1, C2, are run as motors so as,
by their counter electro-motive force, to cut down the potential, and are connected
between the 115 volt and the 110 volt bars. Instead of running some as motors
and some as generators all might be run as motors or all as generators.
As will be seen each auxiliary generator as, for instance, generator C, being
connected at one terminal to a bus-bar A', and at its other terminal to the bus-
bar A, to which one or more main generators are or may be connected, is run in a

page_text: connection between the bus-bar A³, and the main generator or generators and
serves to raise or lower the bus-bar potential above that which it would be if the
main generator were connected direct. to it.
The said motor and dynamo armatures of the supplemental or auxiliary
generators may be coupled together in any desired way so that the electro-motive
force expended as power in the motors may be utilized in the generators, or in the
driving power of any part of the system.
For simplicity the armatures may be all mounted on the same shaft and a
motive power applied by means of an electric motor C, run from the standard or other
bus-bars, as shown, so that the excess of power in the counter electro-motive force
motors will be returned to the general system as electro-motive force in a manner
well understood in the art. The said supplemental armatures might be run by belt
or other mechanical connections with the driving power of the station with the
same advantage.
The supplemental armatures are provided as shown with suitable galvanometers
and switches for throwing them into and out of circuit, and their field magnets are
energized in any suitable way, but conveniently from the station bus-bars as shown.
Suitable field regulators a¹, are provided for adjusting the electro-motive force of
the armatures as required to maintain or vary the bus-bar potentials as described.
In this system such variations and adjustments of potential can obviously be made
without adjustment of the main station dynamos. It will of course be understood
that the armatures of the machines C, C1, C2, C3, are specially wound with relation
to the maximum current which it may be desired to take off the bus bars A³, A*,
A', A, through such machines.
Feeder wires supplying mains 3, 3, are indicated by the numerals 4, 5, 6, of
which 5, is the cential or neutral feeder and 4, 6, the outside or exterior positive
and negative feeders. As will be readily understood each feeder is representative
of a set of feeders as indicated by the dotted lines. The feeders are shown in two
systems each connected to its own switch D, D. Although but two systems and
two switches are shown, it will be understood that the number may be indefinitely
increased, the connections being all similar.
Each switch D, is constructed to operate on the feeders 4, 6, for the two sides of
the system at once, and to transfer said feeders from any bus-bar to any other at
pleasure through connections d, d¹, running from the bus-bars to the contacts f,ƒ³,
of the switch, as clearly shown in the diagram, d, f, being the connections and
contacts for one side of the three wire system and , f, those for the other side.
The switch may be actually constructed as shown in Fig. 6. The switch lever or
bar H, of insulating material carries the two metal segments h, h¹, as clearly shown
in the detail view by the dotted lines, which segments are adapted to bridge the
spaces between the contacts f,f', and the feeder terminals i, i, to which the feeders
are directly connected as shown. These segments or contacts i, i, are preferably
formed on a single plate cut away as shown to form blank spaces over which the
movable segments h, h', may rest in the position shown in the detail plan.
It will be obvious that this construction furnishes a means whereby the feeder
terminals may be switched into and out of connection with the several bus-bars at
pleasure the connection of both sides of the system being controlled in one and the
same operation.
F, indicates what I term a booster switch inasmuch as it controls the connection
of the regulable source of electro-motive force with the feeder terminals in the
operation of switching. This switch operates upon both sides of the system being
provided as shown with the double switch arms in connection respectively with the
plates i, . The switch levers are adapted to engage the contacts m, m', which
being connected directly with the poles of the boosters constitute booster
terminals.
The supplemental electro-motive force generators typified at G, G', (Fig. 1,) as
consisting of dynamo electric machines and provided with suitable means for
varying or adjusting their potential or electro-motive force capacities, such devices

page_text: being here shown as consisting of the regulable resistance boxes g, connected into
the field circuits of said machines. The armatures of said machines are connected
as shown to the standard bus-bars A, A', at one terminal, their free terminals being
joined with the contacts m, m¹.
If both run as generators it is obvious that they will raise the potential of the
contacts m, m³, or of the feeder terminals when connected to the said contacts, and
that by operating the regulating devices the potential at the feeder terminals when
connected through the booster switch may be adjusted as described.
It will be obvious that these supplemental generators might be connected to the
bus-bar of lowest potential and always operate to raise the potential at the booster
switch but by connecting them to an intermediate potential and by providing
suitable devices for reversing the action of said supplemental generators they may
be used to either lower or raise the potential at the booster switch by operating to
assist or oppose the potential of said intermediate bus-bar. If connected to the
bus-bar of highest potential it is obvious that they would always have to be run to
oppose such potential. Being connected, in the manner shown, to the intermediate
potentials, I provide suitable means for reversing the motions of the armatures or
for reversing the field or for otherwise reversing their action as may be desired so
that they may cut down the 115 volts potential in the direction of 110 volts or
raise it to the 120 volts.
In the drawings, Fig. 1, the armatures are shown as driven by an electric
motor G³, which is connected to a bus-bar of the system or is otherwise supplied
with electric energy and which may have its speed and power governed by a
suitable resistance box g¹, or other controller. A reversing switch g², may serve to
reverse the motor. Instead of reversing the motor, the fields of the machines G, G',
might be reversed by means of switches 93, as indicated, to produce the same
effect.
K, K', indicate suitable differential measuring instruments for the two sides of
the system respectively. These instruments are designed to measure or compare
the potentials of a feeder terminal and a booster terminal and to allow the booster
terminal potential to be adjusted to conform to that of the feeder terminal before
the booster is connected thereto. They also serve as a means for comparing the
potential of the bus-bar terminal for f¹, with that of the feeder and booster
terminal when the two latter are connected as will be presently described.
From one side of each of these differential instruments connections are carried as
shown to the contacts p, p, placed in propinquity to contacts r, r', which latter are
in connection with the booster terminals by attachment to the contacts m, m³.
Switch contacts P, P', serve to connect at pleasure the contacts p, r, and p', "'.
The contacts P, P', are preferably mounted on the levers of the switches F, but
insulated therefrom, as shown, and the contacts with which they engage are so
arranged that connection may be made with the measuring instruments without
connecting the feeder terminals with the boosters.
As will be seen the first movement of the levers of switches F, will make the
connection between the boosters at one side of their differential measuring instru-
ments, while the continuance of the movement will connect the feeder terminals and
the booster terminals by the contacts
m,
m².
The other sides of the differential receiving instruments are connected with
contacts & and s¹, and also with contacts t and . The latter contacts serve as
switch contacts for connecting the feeder terminals to the measuring instruments,
they being for such purpose in position to be engaged by the lever arms of
switches F, when the latter are turned to connect the boosters to the
instruments K, K¹. The contacts s, s¹, operate in conjunction with contacts x, x',
and the segments h, h', as switch apparatus for placing one side of the differential
receiving instruments in connection with bus-bars corresponding with the several
bus-bar segments f,f', of the feeder switch. As will be seen the arrangements are
such that the lever H, may take the position of disconnection without bridging
contact segments i, f, or i¹, f.

page_text: The differential instruments K, K', connect by wire 10, with the neutral
bus-bar A, or with other point which will permit the potentials to be measured as
hereinafter described.
The general operation of the apparatus in making the transfer of a feeder or
feeders from a source of one potential as the bus-bar to a source of another
potential, as another bus-bar, would be as follows:-
Switch F, is first partially turned thus connecting the booster and the said feeder
or feeders with the measuring instruments by the contacts t, r, and the booster or
supplemental generator is run and regulated until the differential receiving
instrument indicates the same potential of feeder terminal and booster terminal.
When this condition is attained it is obvious that the switch may be turned to
connect the booster terminal direct to the feeder terminal by the contact m or m³,
without disturbance. The feeder now receives current through two paths, one
direct through the feeder switch and the other through the supplemental armature,
and the feeder switch arm H, may now obviously be turned to open circuit at a
contact for f, without disturbing either the load carried on said feeder or the
operation of the station. The switch H, is now brought to position to connect the
contact or ', corresponding to the feeder switch contact and bus-bar to which
the feeder is to be shifted, but said feeder still remains out of connection with the
said bus-bar to which it is to be shifted. By switch contacts x, s, the measuring
instrument is connected with a bus-bar and the potential thereof may obviously be
compared with that of the feeder terminal and booster terminal which are connected
by the switch F. The booster or supplemental generator is now regulated until
the measuring instrument indicates that the feeder terminal has been brought to
the potential of the contact f, or f, to which it is to be shifted. The feeder switch
is then closed on the contact corresponding to said potential which may obviously
be done under such circumstances without detriment or disturbance. The feeder
is now receiving current through two paths one from a bus-bar through the booster
and the other direct from another bus-bar. Under this condition it is obvious that
the booster switch may be now opened leaving the feeder connected with the
bus-bar to which it is to be transferred, the operation being thereby completed.
It will be understood that in the movement of the switch F, to connect the free.
terminal of the booster with the feeder the contact lever will have moved fully
over the contact t or t¹, so that the feeder will not then be in connection with both.
sides of the differential receiving instrument.
It will be obvious that by regulating the boosters the resultant potential of the
free terminal of said boosters may be either raised or lowered as the circumstances
may require in order that said potential may be made the same as that of the feeder
terminal, and that in the same manner the electro-motive force of the booster may
be varied for the purpose of varying the feeder potential and bringing it to.
coincidence with that of the switch terminal to which the feeder is to be transferred.
When the booster is connected to an intermediate potential as shown in the
drawings, it will be obvious that the same may be operated as the source of a
supplemental electro-motive force which would tend to lower the initial potential
of the bus-bar to which it is connected when a transfer of a feeder is to be made
from a bus-bar of one potential to a bus-bar of a lower potential; or in case of
transfer from a lower to a higher then the boosters would be operated in the
reverse manner.
I do not limit myself to any particular means for measuring or comparing the
potentials of booster terminal, feeder terminal, and bus-bar switch terminal, as
voltmeters and other well known potential indicating equivalents may be employed.
As for instance two distinct voltmeters may be used and may be connected
respectively as the two sides of the differential galvanometer. In this case the
two voltmeters indicate the same potential when the switch is to be moved. I
prefer, however, to employ the differential measuring instrument with switches and
connections as shown since by this means the switching operation may be more
rapidly conducted.

page_text: It will also be understood that in the place of dynamo boosters such as shown,
any source of regulable potential or regulable electro-motive force might be
employed without departing from the invention.
While I have described a peculiar construction and arrangement of switch
devices adapted to make connections as described, I do not wish to be understood
as limiting myself to special mechanical constructions and arrangements as many
others might be used to produce the same changes of connection as will be well.
understood by electricians.
The term booster" is intended to include any source of electro-motive force
which may be interposed in the connection to the feeder in the manner described,
and regulated to raise or lower the potential of the feeder terminal in connection
with the switching operation or transfer of said feeder from one potential source
to another.
In the arrangement thus far described I have assumed that the distinct graded
station potentials are obtained from an initial source of potential by means of
supplemental electro-motive force generators such as electro dynamic machines
interposed in the connections and acting in series with the initial source so as to
raise or lower the potential of said initial source to the requisite point or potential
difference on the so-called auxiliary bus-bars.
While it would be possible to obtain the same gradation of potential by continued
direct connection to the said auxiliary bus-bars at all times of one or more main
dynamos initially adjusted or constructed, nevertheless in many cases this method
is objectionable if it be employed under all conditions of station working especially
in larger stations where the units of generating capacity are relatively large.
During those parts of the day when the load is light the combined output of
current from all the bus-bars may be only sufficient to load properly one or two
units, whereas, owing to the necessity of using at least one dynamo to each bus-bar
to develop and maintain the requisite potential at said bus-bar, this load will be
divided among several units all running at light loads. Moreover, with relatively
large units, since the loss in machinery due to friction and other causes is to a great
extent independent of the load, it follows that the efficiency, (or the ratio of the
useful to the total energy developed), will be very small at light loads. This is
particularly true of dynamos directly coupled to compound engines, wherein the
engine friction when running light may absorb a large proportion of the total
power developed by the engine. By the use of boosters or supplemental generators,
counter or assisting, in the manner hereinabove described, to develop the auxiliary
bus-bar potentials, the whole load can be concentrated into two units for the
ordinary three wire systems, one for each side of the neutral bus-bar.
In the modification I now proceed to describe, the objections just mentioned are
overcome entirely and the use of dynamos connected directly to the auxiliary
bus-bars is made a feature of great utility and convenience, as well as economy in
the operation of a central station. This is accomplished by employing for the
auxiliary bus-bars, boosters and dynamos, together or singly as the circumstances
may determine, and as I proceed to explain.
Instead of making the boosters of such construction that they can carry the
whole current load supplied from the auxiliary bus-bars, I now make them of
smaller current capacity, such for instance, as would be equal to about three
quarters or seven eighths of the current carrying capacity of the armature of one
of the station dynamos.
If several units or sizes of dynamos are used this rating of the booster capacity
is made with reference to the smallest unit. Although the efficiency of these
dynamos is very low at light loads, it rises towards its normal point at loads of
three quarters or seven eighths of normal capacity. There is, it is evident, a
critical capacity or load for each dynamo, at which the efficiency loss, from all
sources will balance the losses caused by the boosters, either by the heating of their
resistance or the friction of their bearings. At this point it evidently makes no

page_text: difference, so far as economy is concerned, whether I use a booster or a dynamo for
producing the auxiliary bus-bar potential.
In order to utilize this circumstance I arrange the circuits in such a way that
any dynamo can be connected onto any bus-bar.
In Fig. 2, I show an arrangement of switch apparatus for this purpose where
each dynamo connects to a dynamo bus, from which the connection may be made
to any of the feeder bus-bars, by means of devices which I symbolize in the
diagram in the form of plug connections 20, 20, 20.
The booster system is arranged as in the previous figures, suitable provision
being made for connecting and disconnecting them from the bus-bars as for instance
by a plug switch.
In the operation of the system, so long as the load is too light to make it
economical or expedient to employ separate dynamos for the auxiliary bus-bars,
the auxiliary bus-bars receive their current from the main bus-bars, through the
booster armature in passing through which the potential is suitably raised or
lowered. When the load reaches a point where the auxiliary bus-bars have to
carry more load than the booster can carry, a separate dynamo is started and
after being brought to the proper potential, is switched directly onto said
auxiliary bus-bar, thereby relieving the booster, which may now be entirely
disconnected.
If the load should further increase until the separate dynamo feeding the
auxiliary bus, is fully loaded, the booster can again be connected so as to take part
of the load and when the load has sufficiently increased to load both the dynamo
and booster, another separate dynamo can be connected to the auxiliary bus.
Thus the booster serves as a means of carrying loads which could not be
economically carried by the dynamos direct; and on the other hand, by thus
combining the two factors (dynamo and boosters), the initial capacity and cost of
both is minimized. This part of the invention is not dependent upon the use of
bus-bars of graded potentials as bars of the same potential might be employed and
suitable equalizers of potential on the feeding wires themselves employed after the
manner heretofore practised in the art.
As will be obvious the gradations of potential of the main dynamos might be
secured not by regulation but by providing dynamos whose primary capacity
unadjusted should be different; but as the differences of potential are not very
great the range of adjustment of machines of the same primary or rated capacity
may be depended upon to give the required differences of potential upon said
bus-bars.
I have in the foregoing described one way that may be used for regulating the
potential of a feeder terminal, such way consisting essentially in the use of a
regulable source of electro-motive force, but I do not wish to be understood as
limiting myself to the use of such a device, as it is well known to electricians that
the electric potential of a conductor or a switch or contact terminal connected
thereto may be varied or adjusted in other ways, one of which being by the use of
a variable resistance such as a rheostat.
A rheostat as used in the invention is illustrated in Figs. 3, 4 and 5, and
described below.
In Fig. 3, A, is the neutral bus-bar, A³, A³, are bus-bars of one polarity though
of different potentials and A, A, are two auxiliary bus-bars of contrary polarity
and different potentials. In practice the potential at any bar of one polarity
differs from that contiguous thereto by from 5 to 25 volts, according to conditions.
While I have shown two auxiliary bus-bars of each polarity, I desire to have it
understood that any number can be used. The different potentials for the regular
and the auxiliary bus-bars may be produced in many ways. In the drawings I
show dynamo electric machines B', B, etc., of the usual constant potential type
connected between the neutral wire and each individual bus in the well known way
as practised in central stations operating the "Edison" constant potential system.
B

page_text: I show but two of the bank of machines similarly arranged and connected to
switches, and others are to be provided in sufficient number to supply all the
bus-bars as seen in Fig. 1.
In Fig. 3, I show three sets of three wire feeders F, F, F³, which convey
current from the station to the mains or consumption circuits f¹, f, f³, for electric
lamps or other translating devices each bus supplying any number of feeders or
sets of feeders desired. Each set of feeders is provided as usual with positive and
negative fuses 9, 92; ampère meters h, h2, and also with a switch S, for connecting
it with the bus-bars. In this case, however, this switch, which I call hereinafter
the feeder switch, is constructed in such manner that it can be used to connect at
will the corresponding feeder with any pair of bus-bars A', A2, as shown in the
case of feeder F, or bus-bars A³, A' (feeder F), or bus-bars A5, A6, (feeder F³).
In addition to the above connections each feeder terminal also connects with a
switch Cº. As shown in the drawings, the switch C6, has its movable arms c³, c³,
in connection by the leads 1, 2, with the movable arms e¹, e², of a pair of
rheostats E, E², hereinafter mentioned. The contact points of the switch C³, are
in electrical connection with the feeders except the neutral wire (in three wire
system or the common return wire in two wire system) which does not connect with
switch C. Thus the positive and negative leads of feeder F, connect with switch
contacts c, c, those of feeder F, with contacts c³, c, those of feeder F³, with
contacts c, c, and so on for any number of feeders, there being a pair of contacts
for each pair of leads (positive and negative) of every feeder starting from the
station. This switch merely serves the purpose of connecting a feeder terminal to
the circuits and apparatus used in the transfer operation and may be indefinitely
varied in construction and arrangement as will be well understood by electricians.
The transfer rheostats E', E³, are shown of the regular circular dial type, but
may be of any form. It is desirable, however, that the contact arm e³, be arranged
so that it can leave contact with the dial at either end of the resistance (e³, or e¹).
The first and last contacts are connected by leads (3, 5, 4 and 6,) with the contact
arms (d', d³, d, d, respectively), of a switch D', whose stationary contacts connect
with the bus-bars as follows:-d, to A¹; d', d, to A³; d, to A'; d, to A³;
de, do, to A*; d, to A. The circuit connections 3, 5, 4, 6, include fuses or
cut-out devices i, i, and ampère meters H, H². The contacts and connections
provided by this switch permit the connection of the terminal of the rheostat to
any two of the bus bars and also serve to break a connection of one terminal with
its bus-bar leaving the other connected. This switch may be indefinitely varied in
construction and under some conditions it would not be necessary to provide for
shifting the terminals of the rheostat to different bus-bars, the connection being in
such case always with the same bus-bar. The special construction of switch shown
merely provides in the same mechanism the means of shifting and of making and
breaking connection.
The switch contacts d', d, and do, do, are connected by wires 7 and 8,
respectively, each circuit with a voltmeter or galvanometer G, G³, the connections
from the other terminals of which is continued by wires 9, 10, to the feeder transfer
connections 1, 2, respectively. When thus connected the voltmeters or galvanometers
must be polarized and arranged so as to read both ways from the zero point. They
may be connected to contacts d³ and de, or d", and d¹, instead of d', d, and d³, d¹³
in which case the voltmeter may be of the ordinary description adapted to read
only one way. The arrangement shown is preferred because the voltmeter then
stands at zero when both its terminals are connected to the middle bus-bar which
is usually the main station potential; and indicates the rise or fall of potential
when one of its terminals becomes transferred to any of the other bus-bars. The
rheostats E, E³, are provided each with an additional pair of contacts e³, e
insulated from the others and so disposed that the moving arm e¹, will come in
contact with either the one or the other (according to the direction it moves in
before coming into contact with the regular resistance contacts. These single
.

page_text: contacts are connected by wires 11, 12, respectively, to an alarm device such as an
electric bell k, or lamp 1, the connection being continued by wires 13, 14,
respectively as shown.
As an illustration of the one method of transfer by the use of the hereinabove
described apparatus, let it be desired to transfer a feeder (such as F³), connected
with the bus-bars A, A2, of lowest potential to other bus-bars A³, A₁, of higher
intermediate potential.
The switch C, is first moved so as to bring the leads 1, 2, into connection with
the contacts c³, c, which join the feeder F2, at the points shown on the drawings
thereby bringing the feeder terminal into connection with the moving contact arms
of the transfer resistance E1, E2, which are in the position shown in the drawing,
that is to say, not connected with either end of the resistance.
The switch D', is now moved so as to connect in the position shown in the
drawings. By this operation the resistance at the rheostat E, E, becomes con-
nected across between the bus-bars A', A³, and A2, A', respectively, as may be seen
from following out the circuits.
It should be noted that the stationary contacts do, do, of the transfer switch D',
are wider than others and are so disposed that they make contact first when the
switch is moved to the position shown. The contacts d³, and d¹³, are also wider
and are disposed so as to make contact first when the switch is moved in the
opposite direction. By the closing of the switch C, a circuit connection is made
through the voltmeters G1, G2. In the case assumed the feeder F2, being connected
with the bus-bar of lowest potential while the contacts do, do, respectively, are at
the intermediate potential, it will readily be understood by following the circuits
that the galvanometers or voltmeters G1, G2, will be submitted to a difference of
potential equal to that existing between said bus-bars A', A³, and A², A'.
The deflection serves to indicate the amount of said difference of potential as
well as its direction, that is to say, whether the potential of the feeder which is to
be manipulated is higher or lower than the intermediate bus-potential; the
deflection being to the left when the feeder is connected to the lowest potential
and to the right when it is connected to the highest while it is at zero when it is
connected to the same potential.
The next step is to move the arms of the switch handles or rheostat arms e¹, e²,
to put the feeder terminal in connection through the resistance with a bus-bar with
which said feeder is already connected. The deflection of the galvanometer gives
the necessary indication from which can be determined the proper direction in
which these handles are to be moved.
The alarm device k, however, provides a safe-guard, by means of which any
error in the motion of the switch is effectually prevented. The switch handles e¹, e³,
should be moved to the same end of the resistance el, e², that the feeder is connected
at, namely (in the particular case supposed)-at that end of it which is connected
with the bus-bar of lowest potential. As will be seen in the figure, this is the end
which is designated by the contacts e³, e³. Hence as the isolated contacts e³, e³, are
at the same potential as the bus-bars A, A2, to which the feeder F, is connected,
the motion of the arms e¹, e², so as to close with the contacts e³, e³, will cause no
current to pass through the alarm devices K.
If, however, the arms e¹, e², had been moved to the right instead of to the left
so as to touch the contacts e, which are in electrical connection with the bus-
bars A, A, it will readily be seen that the difference of potential between the
bus-bars A', A³, or A2, A', would have acted upon the alarm device and
thereby have given notice to the operator that the switch is moved in the wrong
direction.
In the condition shown in the drawings, therefore, the switches must move to the
left. It will be seen that as they move to the left only that resistance which is at
the right of the contact arms is in circuit across the bus-bars or in circuit between
the feeder terminal and the bus-bar of higher potential. The further these.
arms e, e, are moved the less of this resistance remains in circuit. Consequently

page_text: the current which passes from the highest bus-bars A³, A', to the lower potential
bus-bars A1, A2, respectively, will greatly increase, as will be shown by the
increased deflection of the ampère meters H', H2. The operator keeps the arm
moving until these deflections are found to be approximately equal to deflections
which are shown at the ampère meters h', h², of the feeder which is to be transferred.
The switch e', e², is then stopped in that position while the switch D', is moved so
as to partially open, that is to say, so as to make it leave contact at the contact
points d', de, the contacts &, do, owing to their shape and arrangement, still
remaining connected.
It will be seen that by this operation the end of the resistance E¹, E³, which is
connected to the bus-bar of lower potential A', A', has now become disconnected.
In this condition the feeder F, is receiving its current from the sets of bus-bars,-
directly from the bus-bars A, A2, and from the bus-bars A³, A', through that
portion of the system which still remains interpolated at the rheostat, so as to
bring the current to the proper point. As the current has been adjusted at H1, H2,
so as to be the same as that indicated through the feeder ampère meters ¹, h², it
follows that an amount of current equal to the load of said feeder is now being
taken from the higher bus-bars and conveyed to the lower bus-bars so as to supply
in whole or in part the one or more feeders connected to said bar. In this condition
the potential would be practically the same at the point of feeder connection
with A, as it would be at the point where it connects with the large
resistance E¹, E. The switch S, is now opened so as to open the direct connection
between the feeder F, and the bus-bars A1, A2, still leaving the connection through
the leads 1 and 2, switch C, leads 1 and 2, rheostats E', E³, ampère meters H', H³,
switch D', etc., and bus-bars A³, A*.
The rheostat handles e¹, e³, are then moved further in the same direction as
before, until the resistance in the rheostat is gradually cut out altogether which
occurs when the handles reach that end of the resistance near the isolated
contacts e, e. By this operation the resistance E', E², which served before to
produce an artificial drop in the feeder F2, after it was disconnected from the bus-
bars A' A², has become entirely removed and the feeder F2, is now at the potential
of the bus-bars A³, A³.
The switch S, is now moved so as to connect with the contacts leading from the
bus-bars A, A, that is to say, the position shown for feeder F¹. The rheostat
handles e¹, e, are now moved so as to bring it midway between the two ends and
the switches D', may now be open.
If it is desired to transfer a feeder from the intermediate potential to a higher
potential the operation is the same excepting that the switch D', will have to be
turned to the right instead of to the left.
In case it is desired to transfer a feeder from a bus-bar of higher to a bus-bar
of lower potential, the operation is inverse and as follows:-
Let us suppose that it is desired to transfer a feeder such as F³, from the highest
potentials A, A, to the intermediate potential A³, A.-The switch C, is brought
into contact by contacts c³, c6, with the terminal of feeder F³, by which operation
the feeder to be transferred is brought into connection with the rheostat circuit.
The switch D, is then partly moved so as to close the contacts d³, d, with the
stationary contacts d², d, but not far enough to close the contacts d', ds. The
rheostat handles e', e2, are then moved so as to connect with the proper end of
the transfer rheostat resistance.
It will be found in this case that the alarm bell k, would ring if the switch were
moved to the left, but would not ring if moved to the right which is the correct
position.
The switch S, is then opened disconnecting the feeder from a bus-bar direct at
switch S, but leaving its terminal connected by way of the rheostat, after which
the rheostat handles e', e², are moved to the right.
It will be noticed that the galvanometers G1, G2, will swing back towards zero
as the resistance is gradually increased in the transfer rheostats E', E². When

page_text: these galvanometers or voltmeters G1, G2, indicates zero, the condition is such that
the resistance which has been added in circuit with the feeder F³, is sufficient
to cause a drop such that the potential difference at the points where the feeder
connects with the rheostats E', E², is the same as that of the intermediate bus-
bars A, A. In this condition the switch D', can now be fully closed to the right
so as to close d', with d, and d², with d", and the switch S, may now be turned so
as to connect the feeder with the intermediate bus-bars A³, A', or the position
shown for feeder F. The switches D¹ and C6, may now be opened, and the
handles e¹, e², turned to central position leaving the apparatus ready for the next
operation.
The transfer from the bus-bars A³, A, to the bus-bars A', A', is accomplished
in the same manner with the exception that the switch D¹, is turned to the left
instead of to the right.
Fig. 4, shows a somewhat simplified form of apparatus for practising this
invention, the switch D2, being arranged to control the connection of one terminal
only of the rheostats with the bus-bars. The switch serves to shift the rheostats
from A³, to A, and from A, to A. The connection of the alarm contacts with A³,
or with A, is also controlled by means of an ordinary switch attachment at 45.
The transfer from a lower bus-bar as A', A2, to an intermediate bus-bar as A³, A*,
proceed as follows:-
Move switch C6, to connect the feeder terminal with the rheostats; -move
switch D², to the position shown in the drawings, thus connecting the rheostats
with bus-bars A³, A-move rheostat handles e', in clockwise direction until the
ampère meters give equal readings (if by mistake the attempt should be made to
move the rheostat handle to the left so as to connect the feeder direct to the bigher
bus-bar, it is obvious that the alarm would be sounded)-disconnect feeder by
switch S, from bus-bar A¹;-continue movement of the rheostat handles cutting
out resistance in a direction to raise the potential of the feeder terminal until the
voltmeters connected to the middle bus-bars show zero;-connect the feeder to the
bus-bars A, A, direct by the feeder switch and open switch C, and restore
the arms of the rheostats to position for another operation.
To shift from A³ to A, and from A³, to A6, proceed in the same manner
excepting to move switch D2, to the left to connect with the higher bus-bars A°, Aº.
To shift from a higher to a lower potential bus-bar, connect the terminal of the
feeder to the rheostat by switch C, and move switch D', to connect the rheostat to
the bus-bar to which the feeder is connected by the feeder switch ;-close the
rheostat arms to the left or counter clock-wise. Should by mistake the rheostat
handles be moved to the right, it is obvious that the alarm will be sounded, said
alarm being connected by supplemental switches and connections at 45, with one or
the other of the bus-bars of different potential from that which is to be shifted.
This switch 45, also controls the connection of the alarm when the switch D², is in
the opposite position and the transfer is being made in the manner first described
in connection with Fig. 4.
The feeder having been connected with the same bus-bar by the rheostat handles
it may be disconnected from said bus-bar by the switch S-move the rheostat
arm counter clockwise until the voltmeters indicate the potential of the bus-bar to
which the transfer is to be made.
If the potential indicators be on the intermediate bus-bars and the transfer is to
be made to said bar, it is obvious that they will show zero.
Close the transfer switch of the feeder on the bus-bars of lower potential.
Open switch C, and rheostat arms as before.
Fig. 5, shows the invention applied to one side of the three wire system and in
simpler form. The rheostat in this instance is supposed to be permanently
connected to the bus-bar of highest potential and the switching or changes of
connection necessary under different conditions is obtained by allowing the arm on
the rheostat to close connection in either direction but to stand in normal position
out of circuit with the rheostat itself.

page_text: The tension indicator G, may be connected to any bus-bar but preferably to the
middle one. As before, the indicator G, should be polarized to read in both
directions if it be connected to the intermediate bus-bar. It will be understood,
however, that it might be connected to any other bus-bar.
The operations would be briefly as follows
•
To transfer the feeder from A³, to A, first switch the feeder terminal by C, to
arm E, of the rheostat. This gives an indication at G, and shows which way the
arm e', should be moved;-move the rheostat arm to the right clockwise thus
-closing the connection at the opposite end of the resistance from that connected
at A, through the whole resistance which should be of proper amount depending
upon the maximum difference of potential between the bus-bar to which it is
permanently connected and the lowest of the bus-bars which are concerned in any
transfer operation ;-the movement of the rheostat is continued to the right
-clockwise until the current indicated at H, equals that indicated at ';-open the
feeder transfer switch;-continue movement of e', until the indicator G, shows a
potential at the feeder terminal the same as A. This indication would not be
."zero
"when connected to the middle bus ;-throw the feeder switch S, onto the
middle bus A;-open switch C, and throw arm e', in either direction to open
position.
To transfer from A to Aº, proceed in the same way.
To transfer from A, to A, first connect C, to the feeder ;-move arm e¹,
backward or counter clockwise until it closes the connection at e², with the
bus-bar A-open feeder switch S,-continue movement of arm e, in the same
direction until G, shows proper drop to give a bus-bar potential of A', on the
feeder; switch the feeder by S, onto A';-open switch C, and move arm e¹,
around to open circuit position or, if desired, move arm e', in, the same direction
first and then open C.
To shift from A', to A2,-close switch C, on feeder ;-move rheostat handle to
the right thus connecting feeder to A, through the whole resistance and continue
movement clockwise until G, shows potential of A';-open switch S, disconnecting
feeder from A*;-move arm e', back or counter clockwise to e³, or to position
where G, will indicate the potential of A³ ;-close the feeder switch on A² ;-
open e¹, at e³, and then open C³.
It will be obvious to electricians that the present invention is not confined to
continuous current systems but might be used also in alternating current systems
the character of the rheostats which are employed being properly varied for such
purpose and their inductance, their capacity or impedance being changed by any of
the means known in the art.
By the term "rheostat" I mean to include any device consisting of coils or
lengths of conducting wire, as used ordinarily in the art, to form a resistance
without requiring the mechanical movement of parts as is necessary in the case
of an armature wound with conductors and run as the armature of an electric
motor.
It will be obvious that a resistance might be similarly connected in permanent
fashion to the middle bus-bar after the manner of the rheostat shown in Fig. 5, and
used for transferring from bar A², to bar A', while another resistance could be
permanently connected to the higher bus-bar A°, and used for transferring
between A and A. In these instances the resistance would not require to be of
the full capacity of that shown which must be of capacity sufficient for making the
transfer direct from A², to A°. When the three resistances are employed, as
described, each might be used as conditions should require. The connection of
additional resistances as thus outlined is indicated in the dotted lines. The single
resistance, however, whep connected to the bus-bar of highest potential will serve
the purpose of transferring either up or down from any bus-bar to any other, the
resistance being made of proper capacity.
It will be observed that in the case of each of the smaller resistances now

page_text: referred to the permanent connection is to the highest of the two bus-bars between
which transfer is to be made.
It will be obvious that, without departing from this invention, other generators:
of electric energy might be used in place of the main dynamo generators.
supplying the bus-bars and also that other generators of electro-motive force
counter or assisting might be used in place of the motor or dynamo armatures of
machines C, C¹, C³, C³.
Having now particularly described and ascertained the nature of the said inven--
tion and in what manner the same is to be performed, I declare that what I.
claim is :-
1. The herein described method of switching a feeder from a source of one-
potential to a source of different potential consisting in maintaining the load on the
feeder while gradually changing the potential at a terminal of said feeder until it is.
the same as the potential of the source to which the feeder is to be shifted, and
then switching to such source.
2. The herein described method of transferring a feeder from one bus-bar to.
another, consisting in tapping said feeder on to a branch or tap leading from a
source of different potential through a variable resistance, varying the resistance of
said tap or branch until the load indicated on said tap is the same as that indicated
on the feeder, cutting off the feeder connection with its bus-bar, gradually varying
the resistance until the feeder terminal reaches the bus-bar potential of the bar to-
which it is to be transferred and then shifting to said bar.
.
3. The herein described method of transferring a feeder terminal from a bus-bar
of one potential to a bus-bar of a lower potential consisting in gradually increasing
the resistance in a connection between said feeder and a bus-bar of higher potential.
than that to which it is to be shifted, connecting the feeder terminal to the bus-bar
of lower potential and then breaking the connection with the bus-bar of higher
potential.
4. The combination, substantially as described, of a series of bus-bars of graded
potentials, a series of feeders or sets of feeders, switches for shifting said feeders
at pleasure from one bus-bar to another, a potential regulator such as a source of
variable electro-motive force or a variable resistance, and means for varying the
same while connected to a feeder before transfer of said feeder from one bus-bar to.
another.
5. In a system of electrical supply, the combination with a series of feeders or
sets of feeders, of a number of sources of different or graded potentials, switches
for shifting said feeders at pleasure from one bus-bar or source to another, and
means for gradually raising or lowering the potential of any feeder terminal
independently of other feeders or sets of feeders to bring it to the potential of the
bar or source to which it is to be shifted.
6. The combination, substantially as described, of a series of bus-bars of graded
potentials, a series of feeders or sets of feeders, switches for transferring said
feeders from one bus-bar to another, a regulable source of electro-motive force
connected at one terminal to an intermediate potential and provided at its other
with means for connecting it to any feeder for the transfer operation as described,
and means for reversing the operation of the supplemental source to permit it to
oppose or aid the said intermediate potential.
7. The combination, substantially as described, of a series of bus-bars, a series
of feeders or sets of feeders, switches for transferring said feeders from one bus-bar
to another at pleasure, a potential regulator such as a supplemental electro-motive
force generator or a rheostat having means for connecting it to said feeders, a
differential measuring instrument, and means for connecting the two sides thereof
to said regulator and to any feeder simultaneously, as and for the purpose
described.
8. The combination, substantially as described, of a number of sources of
different or graded potential, a feeder, a switch for shifting said feeder at pleasure

page_text: from one source to another, a path or circuit independent of that which connects
the feeder with one of said sources directly, means for connecting the feeder to
said independent path or circuit while said feeder remains connected directly to
said
source, and a potential regulating device in said independent path for varying
the potential at the terminal thereof which connects to a feeder terminal.
9. The combination, substantially as described, of a series of bus-bars, a bank
of main generators with means for connecting and disconnecting them from said
bars, and an auxiliary or supplemental generator or generators of less capacity
provided with means for placing them in a series circuit between the main generator
supplying one bus-bar and another bus-bar.
10. The combination, substantially as described, of a series of bus-bars of
normally different or graded potentials, a bank of main generators with means
for connecting and disconnecting them severally to and from said bus-bars, and
auxiliary electro-motive force generators coupled together and run part as assisting
and part as counter electro-motive force generators in separate connections between
a main generator or generators and bus-bars of different potential.
11. The combination with the bus-bars of different normal potentials, of dynamo
machines adapted to supply the required different potentials directly, switches for
connecting and disconnecting said machines from said bus-bars, auxiliary armatures
run in connections between bus-bars, and means for making and breaking said
connections, as and for the purpose described.
12. The combination with a series of bus-bars of different or graded potentials,
of supplemental or auxiliary electro-motive force generators in series connections
between said bus-bars and main generators of any desired adjustable or primary
potential capacity, and switches controlling the connections of said generators and
bus-bars as and for the purpose described, whereby the said graded potentials may
be had according to the loading of the station either from a uniform main potential
source supplemented as described or from a main generator alone when the load
becomes great.
13. The combination of a potential regulator such as an artificial resistance or a
regulable source of electro-motive force connected across the bus-bars, means for
connecting any feeder terminal to either end of said regulator, and means for
breaking the connection of the same end of the regulator with the bus-bar to which
the feeder is connected.
14. The combination, substantially as described, of bus-bars of different or
graded potential, feeder switches for transferring a feeder from one bus-bar to
another, and a galvanometer or voltmeter having one terminal connected to an
intermediate potential and the other to a switch adapted to connect with any
feeder while the same is connected to any bus-bar.
15. The combination, substantially as described, of a number of sources of
different potential, feeders having switches for transferring them from one source
to another, means for controlling the potential at a feeder terminal to raise or
lower the same gradually prior to transfer, and an electric alarm for giving a
signal when the arm of the controller is moved in a direction to connect the feeder
terminal directly with a source of different potential.
16. In an electric light and power central station, the combination with two
bus-bars of the same sign, of an auxiliary generator of electro-motive force counter
or assisting in a direct connection from one bus-bar to the other, and operating in
a series connection between one bus-bar and the source supplying another bus-bar
direct.
Da shio 17th dow of Ortho- 1002
ALLISON BROS.,
Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in Systems of Electric Distribution.
I, CHARLES ARTHUR ALLISON, of 52 Chancery Lane, London, in the County
of Middlesex, Patent Agent, do hereby declare the nature of this invention (which
has been communicated to me from abroad by Cyprien Odillon Mailloux, of the
City, County and State of New York, U.S.A., Électrician, and William S. Barstow,
of Brooklyn, County of Kings and State of New York, U.S.A., Electrician), and in
what manner the same is to be performed to be particularly described and
ascertained in and by the following statement:-
This invention relates to those systems of electric distribution known as constant
potential systems, so called because the potential difference in the consumption
circuits or mains is maintained constant independently of the load which they carry
or their distance from the source of supply or generating station. It is customary
in practice to maintain these consumption circuits of the required value and
constancy of potential difference by means of so called feeder circuits conveying
electrical energy from the generating station and delivering it to the mains at
various points. Inasmuch as these feeder circuits are not all of equal lengths or do
not carry equal loads, it is found necessary to so proportion their conductivity, by
varying their sectional area, that the loss or drop of potential at full normal load,
will be equal or nearly so in all the feeders. It is found, however, that all the
feeders are not necessarily fully loaded or unloaded at the same time owing to the
location of the mains they supply. Thus, for example, in wholesale and office
districts the greatest load is carried on the feeders in the day time while in residence
districts, the greatest load is reached in the evening. Under such conditions_the
potential of the generators at the station cannot be raised to suit the loaded feeders,
without becoming excessive for the feeders supplying mains which are only partially
loaded. For this reason it has been found almost indispensable to interpose
variable artificial resistance or "feeder equalizers" in the feeder circuits whereby
the drop or fall of the potential in the partly loaded feeders is artificially
increased and regulated so as to maintain a constant potential at the mains.
It is obvious that the energy consumed in heating this artificial resistance is wasted.
The principal object of the present invention is to obviate any loss of electrical
energy in the feeders, beyond the intrinsic loss due to their own resistance.
Another object of the invention is to provide means whereby different potentials
can be successfully employed in the supply or generating station to suit the varying
conditions of loss or drop in the feeders due to their distance and the load they
carry, and to provide means whereby the feeders can be readily and expeditiously
transferred from one potential to a higher or lower one without affecting the rest of
the system or without interrupting or disturbing the service at the mains supplied
by said feeders.
The present invention consists broadly in the use of distinct graded potentials,
however produced, for the several feeder circuits or sets of circuits; each potential
being adapted to a different condition of feeder load or length, with suitable feeders
for shifting the feeders from one potential to another as occasion may require, in
combination with a potential regulator which may be either a source of regulable
electro-motive force or a rheostat adapted to be connected and disconnected from
the feeder terminals and employed to artificially and temporarily vary the potential
of a feeder terminal as an accessory step to the switching operation.
The different graded potentials may be produced either by distinct machines or
banks of machines supplying different bus-bars; or they are derived from the same
initial potential by employing supplemental electro-motive forces to raise or lower
the initial potential, or the two ways may be combined, and one of the features of
this invention consists in such combination.
The invention consists also in the improved combination of apparatus for

page_text: supplying the different graded potentials, according to the load at the station, and
consists in the combination with the several bus-bars of graded potential, of
supplemental electro-motive force generators operating in connection with a source
or sources of uniform initial potential for the purpose of raising or lowering the said
initial potential so as to produce said graded potentials, and main generators of
different adjustable or primary potential capacity which may be used alone to
supply the graded potentials to the bus-bars directly when the station load may
make such use an economical one.
The invention consists further in a means for switching the feeder from a source
of one potential to a source of different potential by artificially bringing the
terminal of said feeder to the potential of the source to which it is to be shifted and
then shifting to such source.
The invention consists further in the special combinations of apparatus as
hereinafter more particularly described and then specified in the claims.
In carrying out the invention any source of regulable electro-motive force or any
variable resistance may be used in the switching operation for the purpose of
artificially changing the potential of the feeder terminal, as hereinafter described,
and in conjunction with such potential regulators suitable switch devices whereby
the said source may be connected to the feeders and disconnected therefrom at
pleasure.
In using a source of electro-motive force as a regulator, it is preferable to
employ for the regulable electro-motive force generator an armature which is used
to vary the potential derived from the main generator or portion of the generator
system by attachment to a bus-bar or otherwise. This supplemental electro-motive
force generator may, by suitable appliances, be employed to either aid or oppose
the potential of the bus-bar to which it is attached so that by connecting it for
example to a ush-bar of an intermediate potential, it may serve to either raise said
intermediate potential to the highest of the graded potentials or to cut it down to
the lowest.
The switch system employed will for convenience be treated as comprising
two parts, one of which is denominated the feeder switch whereby the feeder may
be connected to the different graded potentials, while the other part is denominated
the "booster switch" as it serves to connect the supplemental generator to the
feeders.
This supplemental generator is herein shown as consisting of an electro-dynamic
armature whose power is regulated by any suitable means known in the art, and
which may be revolved by any suitable motive power.
In connection with the apparatus I use suitable measuring instruments, whereby
the potential at the terminal of the booster switch where it is connected to
the feeder, may be compared with the feeder terminal before connection is made
between the booster and the feeder terminal. I also propose to use suitable
means for comparing the potential of a feeder terminal as modified by the booster
with the potential of the bus-bar switch terminal to which the feeder is to be
transferred.
One feature of the invention consists in the combination with the feeders and the
boosters, of a suitable differential measuring instrument, and suitable switch devices
whereby two sides thereof may be connected respectively to a booster terminal and
to a feeder terminal of any of the feeders.
When in the operation of the central station it becomes desirable to change the
feeder from a bus-bar of one potential to the bus-bar of another, it is obvious that
if the feeder terminal be at a different potential from that terminal of the switch
which connects with the bus-bar to which the feeder is to be transferred, there will
be a tendency to sparking on transfer and an interruption or else a disturbance of
the load carried on the feeder and of the general operation of the station; but if
the transfer can be made with a condition of potentials such that the feeder
terminal shall have a potential the same as the source to which it is to be shifted,
then the switching may take place without disturbance.

page_text: In the operation of switching the regulable source is used in the following
manner when a feeder is to be transferred from one bus-bar to the other :-If at
the time a change is to be made, the potential of the feeder terminal be the same
as the potential of the bus-bar to which the supplemental generator is connected
and said generator be not running, it will be obvious that the free terminal pole of
said supplemental generator can be at the same time connected with such feeder
by the switch. In this condition it will be obvious that the feeder will receive
current through the two paths, one through the feeder switch, the other through
the supplemental generator and a booster switch; and under such conditions the
feeder switch may be opened to disconnect the feeder from the source of potential
from which it is to be transferred without disturbing either the load carried on said
feeder or the operation of the station.
The supplemental machine or booster may be now run and its electro-motive
force caused to gradually vary in one direction or the other according to whether
it is necessary to raise or lower the potential of the feeder terminal in order to
bring the potential of said feeder terminal to that of the bus-bar to which it is
desired to transfer said feeder. When this point. has been reached, it is obvious
that in like manner the feeder may be switched to the different potential, after
which the supplemental generator may be disconnected leaving the feeder connected
with the desired bus-bar.
If when the transfer is to be made the feeder be at a different potential from the
free terminal of the supplemental armature or regulable generator, the electro-
motive force of the latter will be varied to add to or subtract from the potential so
as to bring the potential of the booster switch terminal to that of the feeder
terminal. The booster switch can then be closed as before upon the feeder
terminal as before described, after which the regulable generator of electro-motive
force can be varied to bring the feeder terminal potential up or down to the
potential of the bus-bar to which it is to be transferred, and the operation com-
pleted as before.
Before connecting the feeder to the booster switch the potentials of the feeder
terminal and the booster terminal should be compared; for which purpose suitable
electrical measuring instruments may be provided. This comparison I prefer to
make through the operation of a differential measuring instrument, the pointer of
which by standing at zero indicates identity of potential at the feeder terminal and
at the terminal of the booster switch. The same comparison may be made in the
same way between the potential of the feeder terminal and the booster switch
while connected together and the potential of the switch terminal of the bus-bar
or potential source to which the transfer is to be made.
Briefly speaking the plan of operation in switching a feeder from the source of
one potential to another according to this invention, involves firstly, connecting
said feeder to a regulable source whose potential at the feeder terminal is by
suitable means made the same as that of the source from which it is to be
transferred, then disconnecting the latter source and gradually varying the
regulable source until the potential of the feeder terminal is changed to that of
the source to which it is to be shifted, then switching to the latter and finally
removing the regulable source.
In this way it is possible to transfer a loaded feeder from one source of energy to
another, of a different potential greater or less without interfering with the load
and without sparking or other objectionable effect at the switch.
Other features and combinations forming this invention will be specified in the
claims at the end of this description.
In the drawings filed with the Provisional Specification:
Fig. 1, is a diagram of an apparatus by which the invention may be practised,
showing the potential regulator consisting of a source of regulable electro-motive
force.
Fig. 2, is a diagram illustrating that part of the invention which relates to

page_text: combinations of main generators and auxiliary generators for providing the desired
bus-bar potentials under different conditions of station working.
Fig. 3, is a diagram of an apparatus by which the invention may be practised,
showing the potential regulator consisting of a rheostat.
Fig. 4, is a diagram of a simplified apparatus.
Fig. 5, is a diagram of a further modification.
Fig. 6, is an enlarged detail plan of a form of switch apparatus that may be
employed.
In the diagram Fig. 1, the invention is shown as applied to a three wire system,
each side of which is shown as practically a duplicate of the other in respect to
switch contacts, measuring instruments, bus-bars, supplemental variable generators,
etc., but as will be readily understood by electricians the invention may be applied
to other systems as, for instance, to four or five wire systems, or to systems in
which no neutral or third wire is employed. A description of the operation with
reference to one side of the three wire system will be sufficient.
A, A¹, are positive and negative bus-bars, and A2, the neutral bus-bar of a three
wire system, and form terminals of any desired potential fed from suitable
generators as well understood in the art. The potential assumed in the present
case is 115 volts, but might be greater or less. The main source of such potential
is here indicated as consisting of dynamo generators B, B, or banks of generators
with the usual accompaniment of field regulators a, a, for adjusting the potential;
switches b, b, between the dynamos and the bus-bars, voltmeters, galvanometers, and
fuses, etc. Any number of generators may be used suitably connected as shown, and
suitable switches may be provided for connecting and disconnecting them from the
bus-bars A, A1, A2, or from the other bus-bars of the systems. Said main generators
are preferably provided of different regulable or primary potential capacity so that
by suitable connection of them to the bus-bars A, A1, A2, and the remaining bus-bars,
as will be fully hereinafter described, different or graded potentials may be furnished
at the bus-bar board direct without the intervention of the supplemental or auxiliary
electro-motive force generators to be presently described; and said main generators
may be coupled singly or in multiple to the bus-bars.
A³, A, indicate auxiliary bus-bars of a lower potential say 110 volts, and
A, A, auxiliary bus-bars of a higher potential, say 120 volts, secured by the
intervention of the supplemental or auxiliary electro-motive force generators C, C),
C2, C3, applied to raise or lower the potential of the main source to the desired
amount and which are of comparatively small capacity. For this purpose some
may be run as motors to develop counter electro-motive force, and others as
generators to positively supplement the potential; their armatures may be
connected as shown between the bus-bars A, A', of standard or intermediate
potential, and the auxiliary bus-bars of higher and lower potential. Thus the
armatures of C, and C³, run as assisting generators, are connected between A, A',
the 115 volt bus-bars and the 120 volt bus-bars so as to raise the potential,
while C', C, are run as motors so as, by their counter electro-motive force, to cut
down the potential, and are connected between the 115 volt and the 110 volt bars.
Instead of running some as motors and some as generators all might be run as
motors or all as generators.
As will be seen each auxiliary generator as, for instance, generator C, being
connected at one terminal to a bus-bar A³, and at its other terminal to the bus-
bar A, to which one or more main generators are or may be connected, is run in a
connection between the bus-bar A', and the main generator or generators and serves
to raise or lower the bus-bar potential above that which it would be if the main
generator were connected direct to it.
The said motor and dynamo armatures of the supplemental or auxiliary
generators may be coupled together in any desired way so that the electro-motive
force expended as power in the motors may be utilized in the generators, or in the
driving power of any part of the system.

page_text: For simplicity the armatures may all be mounted on the same shaft and a
motive power applied by means of an electric motor C, run from the standard or
other bus-bars, as shown, so that the excess of power in the counter electro-motive
force motors will be returned to the general system as electro-motive force in a
manner well understood in the art. The said supplemental armatures might be
run by belt or other mechanical connections with the driving power of the station
with the same advantage.
The supplemental armatures are provided as shown with suitable galvanometers
and switches for throwing them into and out of circuit, and their field magnets are
energized in any suitable way, but conveniently from the station bus-bars as
shown. Suitable field regulators a', are provided for adjusting the electro-motive
force of the armatures as required to maintain or vary the bus-bar potentials as
described. In this system such variations and adjustments of potential can
obviously be made without adjustment of the main station dynamos. It will of
course be understood that the armatures of the machines C, C1, C2, C3, are specially
wound with relation to the maximum current which it may be desired to take off
the bus-bars A³, A', A5, A6, through such machines.
Feeder wires supplying mains 3, 3, are indicated by the numerals 4, 5, 6, of
which 5, is the central or neutral feeder and 4, 6, the outside or exterior positive
and negative feeders. As will be readily understood each feeder is representative
of a set of feeders as indicated by the dotted lines. The feeders are shown in two
systems each connected to its own switch D, D. Although but two systems and
two switches are shown, it will be understood that the number may be indefinitely
increased, the connections being all similar.
Each switch D, is constructed to operate on the feeders 4, 6, for the two sides
of the system at once, and to transfer said feeders from any bus-bar to any other
at pleasure through the connections d, d', running from the bus-bars to the
contacts f, f, of the switch as clearly shown in the diagram d, f, being the
connections and contacts for one side of the three wire system and d, f, those for
the other side. The switch may be actually constructed as shown in Fig. 6. The
switch lever or bar H, of insulating material carries the two metal segments h, h³,
as clearly shown in the detail view by the dotted lines, which segments are
adapted to bridge the spaces between the contacts f, f', and the feeder terminals i, i¹,
to which the feeders are directly connected as shown. These segments or
contacts i, i, are preferably formed on a single plate cut away as shown to form
blank spaces over which the movable segments h, h, may rest in the position
shown in the detail plan.
It will be obvious that this construction furnishes a means whereby the feeder
terminals may be switched into and out of connection with the several bus-bars at
pleasure the connection of both sides of the system being controlled in one and the
same operation.
F, indicates what I term a booster switch inasmuch as it controls the connection
of the regulable source of electro-motive force with the feeder terminals in the
operation of switching. This switch operates upon both sides of the system being
provided as shown with the double switch arms in connection respectively with the
plates i, . The switch levers are adapted to engage the contacts m, m', which
being connected directly with the poles of the boosters constitute booster
terminals.
The supplemental electro-motive force generators typified at G, G' (Fig. 1),
as consisting of dynamo electric machines and provided with suitable means for
varying or adjusting their potential or electro-motive force capacities, such devices
being here shown as consisting of the regulable resistance boxes g, connected into
the field circuits of said machines. The armatures of said machines are connected
as shown to the standard bus-bars A, A¹, at one terminal, their free terminals being
joined with the contacts m, m'.
If both run as generators it is obvious that they will raise the potential of the

page_text: contacts m, m', or of the feeder terminals when connected to the said contacts, and
that by operating the regulating devices the potential at the feeder terminals when
connected through the booster switch may be adjusted as described.
It will be obvious that these supplemental generators might be connected to the
bus-bar of lowest potential and always operate to raise the potential at the booster
switch but by connecting them to an intermediate potential and by providing
suitable devices for reversing the action of said supplemental generators they may
be used to either raise or lower the potential at the booster switch by operating to
assist or oppose the potential of said intermediate bus-bar. If connected to the
bus-bar of highest potential it is obvious that they would always have to be run to
oppose such potential. Being connected in the manner shown, to the intermediate
potentials, I provide suitable ineans for reversing the motions of the armatures or
for reversing the field or for otherwise reversing their action as may be desired so
that they may cut down the 115 volts potential in the direction of 110 volts or
raise it to 120.volts.
In the drawings Fig. 1, the armatures are shown as driven by an electric
motor G³, which is connected to a bus-bar of the system or is otherwise supplied
with electric energy and which may have its speed and power governed by a
suitable resistance box g', or other controller. A reversing switch g², may serve
to reverse the motor. Instead of reversing the motor, the fields of the
machines G, G¹, might be reversed by means of switches g³, as indicated, to
produce the same effect.
K, K¹, indicate suitable differential measuring instruments for the two sides of
the system respectively. These instruments are designed to measure or compare
the potentials of a feeder terminal and a booster terminal and to allow the booster
terminal potential to be adjusted to conform to that of the feeder terminal before
the booster.is connected thereto. They also serve as a means for comparing the
potential of the bus-bar terminal f, or f', with that of the feeder and booster
terminal when the two latter are connected as will be presently described.
From one side of each of these differential instruments connections are carried
as shown to the contacts p, p', placed in propinquity to contacts r, r, which
latter are in connection with the booster terminals by attachment to the
contacts m, m³.
Switch contacts P, P¹, serve to connect at pleasure the contacts p, r, and p¹, »¹.
The contacts P, P', are preferably mounted on the levers of the switches F, but
insulated therefrom, as shown, and the contacts with which they engage are so
arranged that connection may be made with the measuring instruments without
connecting the feeder terminals with the boosters.
As will be seen the first movement of the levers of switches F, will make the
connection between the boosters at one side of their differential measuring
instruments, while the continuance of the movement will connect the feeder
terminals and the booster terminals by the contacts m, m¹.
The other sides of the differential receiving instruments are connected with
contacts s and s', and also with contacts t and t'. The latter contacts serve as
switch contacts for connecting the feeder terminals to the measuring instruments,
they being for such purpose in position to be engaged by the lever arms of
switches F, when the latter are turned to connect the boosters to the instru
ments K, K. The contacts s, s¹, operate in conjunction with contacts x, x¹, and
the segments h, h', as switch apparatus for placing one side of the differential
receiving instruments in connection with bus-bars corresponding with the several
bus-bar segments f,f, of the feeder switch. As will be seen the arrangements are
such that the lever H, may take the position of disconnection without bridging
contact segments i, f, or i¹, f¹.
The differential instruments K, K', connect by wire 10, with the neutral
bus-bar A, or with other point which will permit the potentials to be measured as
hereinafter described.

page_text: The general operation of the apparatus in making the transfer of a feeder or
feeders from a source of one potential as the bus-bar to a source of another
potential, as another bus-bar, would be as follows:-
Switch F, is first partially turned thus connecting the booster and the said feeder
or feeders with the measuring instruments by the contacts t, r, and the booster or
supplemental generator is run and regulated until the differential receiving
instrument indicates the same potential of feeder terminal and booster terminal.
When this condition is attained it is obvious that the switch may be turned to
connect the booster terminal direct to the feeder terminal by the contact m or m¹,
without disturbance. The feeder now receives current through two paths, one
direct through the feeder switch and the other through the supplemental armature,.
and the feeder switch arm H, may now obviously be turned to open circuit at a
contact forf, without either disturbing the load carried on said feeder or the
operation of the station. The switch H, is now brought to position to connect the
contact or ', corresponding to the feeder switch contact and bus-bar to which
the feeder is to be shifted, but said feeder still remains out of connection with the
said bus-bar to which it is to be shifted. By switch contacts r, s, the measuring
instrument is connected with a bus-bar aud the potential thereof may obviously be
compared with that of the feeder terminal and booster terminal which are connected
by the switch F. The booster or supplemental generator is now regulated until
the measuring instrument indicates that the feeder terminal has been brought to the
potential of the contact f, or f¹, to which it is to be shifted. The feeder switch is
then closed on the contact corresponding to said potential which may obviously be
done under such circumstances without detriment or disturbance. The feeder is
now receiving current through two paths one from a bus-bar through the booster
and the other direct from another bus-bar. Under this condition it is obvious that
the booster switch may be now opened leaving the feeder connected with the bus-
bar to which it is to be transferred, the operation being thereby completed.
It will be understood that in the movement of the switch F, to connect the free
terminal of the booster with the feeder the contact lever will have moved fully
over the contact t or t¹, so that the feeder will not then be in connection with both
sides of the differential receiving instrument.
It will be obvious that by regulating the boosters the resultant potential of the
free terminal of said boosters may be either raised or lowered as the circumstances
may require in order that said potential may be made the same as that of the
feeder terminal, and that in the same manner the electro-motive force of the
booster may be varied for the purpose of varying the feeder potential and bringing
it to coincidence with that of the switch terminal to which the feeder is to be
transferred.
When the booster is connected to an intermediate potential as shown in the
drawings, it will be obvious that the same may be operated as the source of a
supplemental electro-motive force which would tend to lower the initial potential of
the bus-bar to which it is connected wben a transfer of a feeder is to be made from
a bus-bar of one potential to a bus-bar of a lower potential; or in case of transfer
from a lower to a higher then the boosters would be operated in the reverse manner.
I do not limit myself to any particular means for measuring or comparing the
potentials of booster terminal, feeder terminal, and bus-bar switch terminal, as
voltmeters and other well known potential indicating equivalents may be employed.
As for instance two distinct voltmeters may be used and may be connected
respectively as the two sides of the differential galvanometer. In this case the two
voltmeters indicate the same potential when the switch is to be moved. I prefer,
however, to employ the differential measuring instrument with switches and
connections as shown since by this means the switching operation may be more
rapidly conducted.
It will also be understood that in the place of dynamo boosters such as shown,
any source of regulable potential or regulable electro-motive force might be
employed without departing from the invention.

page_text: While I have described a peculiar construction and arrangement of switch devices
adapted to make connections as described, I do not wish to be understood as
limiting myself to special mechanical constructions and arrangements as many others
might be used to produce the same changes of connection as will be well understood
by electricians.
The term "booster" is intended to include any source of electro-motive force
which may be interposed in the connection to the feeder in the manner described,
and regulated to raise or lower the potential of the feeder terminal in connection
with the switching operation or transfer of said feeder from one potential source
to another.
In the arrangement thus far described I have assumed that the distinct graded station
potentials are obtained from an initial source of potential by means of supplemental
electro-motive force generators such as electro dynamic machines interposed in the
connections and acting in series with the initial source so as to raise or lower the
potential of said initial source to the requisite point or potential difference on the so-
called auxiliary bus-bars.
more
While it would be possible to obtain the same gradation of potential by continued
direct connection to the said auxiliary bus-bars at all times of one or
main dynamos initially adjusted or constructed, nevertheless in many cases this
method is objectionable if it be employed under all conditions of station working
especially in larger stations where the units of generating capacity are relatively
large. During those parts of the day when the load is light the combined output
of current from all the bus-bars may be only sufficient to load properly one or two
units, whereas, owing to the necessity of using at least one dynamo to each bus-
bar to develop and maintain the requisite potential at said bus-bar, this load will be
divided among several units all running at light loads. Moreover, with relatively
large units, since the loss in machinery due to friction and other causes is to a great
extent independent of the load, it follows that the efficiency, (or the ratio of the
useful to the total energy developed), will be very small at light loads. This is
particularly true of dynamos directly coupled to compound engines, wherein the
engine friction when running light may absorb a large proportion of the total
power developed by the engine. By the use of boosters or supplemental generators,
counter or assisting, in the manner hereinabove described to develop the auxiliary
bus-bar potentials, the whole load can be concentrated into two units for the
ordinary three wire systems, one for each side of the neutral bus-bar.
In the modification I now proceed to describe, the objections just mentioned are
overcome entirely and the use of dynamos connected directly to the auxiliary bus-
bars is made a feature of great utility and convenience, as well as economy in the
operation of a central station. This is accomplished by employing for the auxiliary
bus-bars, boosters and dynamos, together or singly as the circumstances may
determine, and as I proceed to explain.
Instead of making the boosters of such construction that they can carry the
whole current load supplied from the auxiliary bus-bars, I now make them of
smaller current capacity, such for instance, as would be equal to about three
quarters or seven eighths of the current carrying capacity of the armature of one
of the station dynamos.
If several units or sizes of dynamos are used this rating of the booster capacity
is made with reference to the smallest unit. Although the efficiency of these
dynamos is very low at light loads, it rises towards its normal point at loads of
three quarters or seven eighths of normal capacity. There is, it is evident a critical
capacity or load for each dynamo, at which the efficiency loss, from all sources will
balance the losses caused by the boosters, either by the heating of their resistance
or the friction of their bearings. At this point it evidently makes no difference, so
far as economy is concerned, whether I use a booster or a dynamo for producing
the auxiliary bus-bar potential.
In order to utilize this circumstance I arrange the circuits in such a way that
any dynamo can be connected onto any bus-bar.

page_text: In Fig. 2, I show an arrangement of switch apparatus for this purpose where
each dynamo connects to a dynamo bus, from which the connection may be made to
any of the feeder bus-bars, by means of devices which I symbolize in the diagram
in the form of plug connections 20, 20, 20.
The booster system is arranged as in the previous figures, suitable provision
being made for connecting and disconnecting them from the bus-bars as for instance
by a plug switch.
In the operation of the system, so long as the load is too light to make it
economical or expedient to employ separate dynamos for the auxiliary bus-bars,
the auxiliary bus-bars receive their current from the main bus-bars, through the
booster armature in passing through which the potential is suitably raised or
lowered. When the load reaches a point where the auxiliary bis-bars have to
carry more load than the booster can carry, a separate dynamo is started and after
being brought to the proper potential, is switched directly onto said auxiliary
bus-bar, thereby relieving the booster, which may now be entirely disconnected.
If the load should further increase until the separate dynamo feeding the auxiliary
bus, is fully loaded, the booster can again be connected so as to take part of the
load and when the load has sufficiently increased to load both the dynamo and the
booster, another separate dynamo can be connected to the auxiliary bus. Thus
the booster serves as a means of carrying loads which could not be economically
carried by the dynamos direct; and on the other hand, by thus combining the two
factors (dynamo and boosters), the initial capacity and cost of both is minimized.
This part of the invention is not dependent upon the use of bus-bars of graded
potentials as bars of the same potential might be employed and suitable equalizers
of potential on the feeding wires themselves employed after the manner heretofore
practised in the art.
As will be obvious the gradations of potential of the main dynamos might be
secured not by regulation but by providing dynamos whose primary capacity
unadjusted should be different; but as the differences of potential are not very
great the range of adjustment of machines of the same primary or rated capacity
may be depended upon to give the required differences of potential upon said
bus-bars.
I have in the foregoing described one way that may be used for regulating the
potential of a feeder terminal, such way consisting essentially in the use of a
regulable source of electro-motive force, but I do not wish to be understood as
limiting myself to the use of such a device, as it is well known to electricians that
the electric potential of a conductor or a switch or contact terminal connected
thereto may be varied or adjusted in other ways, one of which being by the use of
a variable resistance such as a rheostat.
A rheostat as used in the invention is illustrated in Figs. 3, 4 and 5, and described
below.
In Fig. 3, A, is the neutral bus-bar; A³, A', are bus-bars of one polarity though
of different potentials and A, A, are two auxiliary bus-bars of contrary polarity
and different potentials. In practice the potential at any bar of one polarity differs
from that contiguous thereto by from 5 to 25 volts, according to conditions.
While I have shown two auxiliary bus-bars of each polarity, I desire to have it
understood that any number can be used. The different potentials for the regular
and the auxiliary bus-bars may be produced in many ways. In the drawings I
show dynamo electric machines B, B2, etc., of the usual constant potential type
connected between the neutral wire and each individual bus in the well known way
as practised in central stations operating the "Edison constant potential system.
I show but two of the bank of machines similarly arranged and connected to
switches, and others are to be provided in sufficient number to supply all the
bus-bars as seen in Fig. 1.
"
In Fig. 3, I show three sets of three wire feeders F, F2, F³, which convey
current from the station to the mains or consumption circuits f', f, f³, for electric

page_text: lamps or other translating devices each bus supplying any number of feeders or
sets of feeders desired. Each set of feeders is provided as usual with positive and
negative fuses g, g; ampere meters h, h2, and also with a switch S, for connecting
it with the bus-bars. In this case, however, this switch, which I call hereinafter
the feeder switch, is constructed in such manner that it can be used to connect at
will the corresponding feeder with any pair of bus-bars A', A, as shown in the
case of feeder 2, or bus-bars A³, A (feeder F), or bus-bars A³, A, (feeder F³).
In addition to the above connections each feeder terminal also connects with a
switch C. As shown in the drawings, the switch C, has its movable arms c', c,
in connection by the leads 1, 2, with the movable arms e¹, e³, of a pair of
rheostats E', E', hereinafter mentioned. The contact points of the switch C, are
in electrical connection with the feeders except the neutral wire (in three wire
system or the common return wire in the two wire system) which does not connect
with switch C. Thus the positive and negative leads of feeder F, connect with
switch contacts c₁, e², those of feeder F, with contacts c³, ct, those of feeder F³,
with contacts c, c, and so on for any number of feeders, there being a pair of
contacts for each pair of leads (positive and negative) of every feeder starting
from the station. This switch merely serves the purpose of connecting a feeder
terminal to the circuits and apparatus used in the transfer operation and may be
indefinitely varied in construction and arrangement as will be well understood by
electricians.
The transfer rheostats E¹, E³, are shown of the regular circular dial type, but
may be of any form. It is desirable, however, that the contact arm c², be arranged
so as it can leave contact with the dial at either end of the resistance (e or e¹).
The first and last contacts are connected by leads (3, 5, 4, and 6,) with the contact
arms (d', d³, d², d', respectively), of a switch D¹, whose stationary contacts connect
with the bus-bars as follows:-d, to A', d, d, to A³; d, to A'; d, to A²;
do, do, to A; d, to Aº. The circuit connections 3, 5, 4, 6, include fuses or cut-
out devices i, i, and ampere meters H, H. The contacts and connections provided
by this switch permit the connection of the terminal of the rheostat to any two of
the bus-bars and also serve to break a connection of one terminal with its bus-bar
leaving the other connected. This switch may be indefinitely varied in construction
and under some conditions it would not be necessary to provide for shifting the
terminals of the rheostat to different bus-bars, the connection being in such case
always with the same bus-bar. The special construction of switch shown merely
provides in the same mechanismn the means of shifting and of making and breaking
connection.
The switch contacts d', d³, and d³, d¹º, are connected by wires 7 and 8, respectively,
each circuit with a voltmeter or galvanometer G, G3, the connections from the
other terminals of which is continued by wires 9, 10, to the feeder transfer con-
nections 1, 2, respectively. When thus connected the voltmeters or galvanometers
must be polarized and arranged so as to read both ways from the zero point. They
may be connected to contacts d' and do, or d", and d¹, instead of d', d, and do, do,
in which case the voltmeter may be of the ordinary description adapted to read
only one way. The arrangement shown is preferred because the voltmeter then
stands at zero when both its terminals are connected to the middle bus-bar which
is usually the main station potential; and indicates the rise or fall of potential
when one of its terminals becomes transferred to any of the other bus-bars. The
rheostats E, E, are provided each with an additional pair of contacts e³, e
insulated from the others and so disposed that the moving arm e', will come in
contact with either the one or the other (according to the direction it moves in)
before coming into contact with the regular resistance contacts.
The single
contacts are connected by wires 11, 12, respectively, to an alarm device such as an
electric bell, or lamp l, the connection being continued by wires 13, 14,
respectively, as shown.
As an illustration of the one method of transfer by the use of the hereinabove

page_text: described apparatus, let it be desired to transfer a feeder (such as F2) connected
with the bus-bars A, A³, of lowest potential to other bus-bars A³, A*, of higher
intermediate potential.
The switch C, is first moved so as to bring the leads 1, 2, into connection with
the contacts c³, c, which join the feeder F2, at the points shown on the drawings
thereby bringing the feeder terminal into connection with the moving contact arms
of the transfer resistance E1, E2, which are in the position shown in the drawing,
that is to say, not connected with either end of the resistance.
The switch D³, is now moved so as to connect in the position shown in the
drawings. By this operation the resistance at the rheostat E¹, E', becomes
connected across between the bus-bars A¹, A³, and A2, A4, respectively, as may be
seen from following out the circuits.
It should be noted that the stationary contacts do, do, of the transfer switch D',
are wider than others and are so disposed that they make contact first when the
switch is moved to the position shown. The contacts d², and d¹², are also wider
and are disposed so as to make contact first when the switch is moved in the
opposite direction. By the closing of the switch C, a circuit connection is made
through the voltmeters G', G. In the case assumed the feeder F2, being connected
with the bus-bar of lowest potential while the contacts do, do, respectively, are at
the intermediate potential, it will readily be understood by following the circuits
that the galvanometers or voltmeters G1, G2, will be submitted to a difference of
potential equal to that existing between the bus-bars A1, A2, and A², A*.
The deflection serves to indicate the amount of said difference of potential as
well as its direction, that is to say, whether the potential of the feeder which is to
be manipulated is higher or lower than the intermediate bus-potential; the
deflection being to the left when the feeder is connected to the lowest potential
and to the right when it is connected to the highest while it is at zero when it is
connected to the same potential.
The next step is to move the arms of the switch handles or rheostat arms e¹, e²,
to put the feeder terminal in connection through the resistance with a bus-bar with
which said feeder is already connected. The deflection of the galvanometer gives
the necessary indication from which can be determined the proper direction in
which these handles are to be moved.
The alarm device k, however, provides a safe-guard by means of which any
error in the motion of the switch is effectually prevented. The switch handles e', e²,
should be moved to the same end of the resistance e', e², that the feeder is connected
at, namely (in the particular case supposed)-at that end of it which is
connected with the bus-bar of lowest potential. As will be seen in the figure, this
is the end which is designated by the contacts ³, ³. Hence as the isolated
contacts, e³, are at the same potential as the bus-bars A1, A2, to which the
feeder F, is connected, the motion of the arms e¹, e², so as to close with the
contacts e, e, will cause no current to pass through the alarm devices k.
If, however, the arus e, e², had been moved to the right instead of to the left so
as to touch the contacts e³, which are in electrical connection with the bus-bars A³, A*,
it will readily be seen that the difference of potential between the bus-bars A¹, A³,
or A2, A', would have acted upon the alarm device and thereby have given notice
to the operator that the switch is moved in the wrong direction.
In the condition shown in the drawings, therefore, the switches must move to
the left. It will be seen that as they move to the left only that resistance which
is at the right of the contact arms is in circuit across the bus-bars or in circuit
between the feeder terminal and the bus-bar of higher potential. The further
these arms e', e², are moved the less of this resistance remains in circuit.
Consequently the current which passes from the highest bus-bars A³, A', to the
lower potential bus-bars A1, A2, respectively, will greatly increase, as will be shown
by the increased deflection of the ampere meters H, H². The operator keeps the
arm moving until these deflections are found to be approximately equal to
deflections which are shown at the ampere meters h³, h³, of the feeder which is to

page_text: be transferred. The switch e¹, e², is then stopped in that position while the
switch D¹, is moved so as to partially open, that is to say, so as to make it leave
contact at the contact points do, do, the contacts do, do, owing to their shape and
arrangement, still remaining connected.
It will be seen that by this operation the end of the resistance E', E², which is
connected to the bus-bar of lower potential A1, A2, has now become disconnected.
In this condition the feeder F3, is receiving its current from the sets of bus-bars,—
directly from the bus-bars A1, A2, and from the bus-bars A3, A4, through that
portion of the system which still remains interpolated at the rheostat, so as to
bring the current to the proper point. As the current has been adjusted at H', H²,
so as to be the same as that indicated through the feeder ampere meters h¹, ², it
follows that an amount of current equal to the load of said feeder is now being
taken from the higher bus-bars and conveyed to the lower bus-bars so as to supply
in whole or in part the one or more feeders connected to said bar. In this condition
the potential would be practically the same at the point of feeder connection
with A, as it would be at the point where it connects with the large resistance E', E².
The switch S, is now opened so as to open the direct connection between the
feeder F2, and the bus-bars A', A², still leaving the connection through the leads 1
and 2, switch C, leads 1 and 2, rheostats E¹, E², ampere meters H¹, H², switch D¹,
etc., and bus-bars A³, A'.
The rheostat handles e¹, e³, are then moved further in the same direction as
before, until the resistance in the rheostat is gradually cut out altogether which
occurs when the handles reach that end of the resistance near the isolated
contacts e, e¹. By this operation the resistance E', E2, which served before to
produce an artificial drop in the feeder F, after it was disconnected from the bus-
bars A', A2, has become entirely removed and the feeder F2, is now at the potential
of the bus-bars A2, A³.
The switch S, is now moved so as to connect with the contacts leading from the
bus-bars A2, A3, that is to say, the position shown for feeder F¹. The rheostat
handles E, E, is now moved so as to bring it midway between the two ends and
the switches D¹, may now be open.
If it is desired to transfer a feeder from the intermediate potential to a higher
potential the operation is the same excepting that the switch D', will have to be
turned to the right instead of to the left.
In case it is desired to transfer a feeder from a bus-bar of higher to a bus-bar of
lower potential, the operation is inverse and as follows:-
Let us suppose that it is desired to transfer a feeder such as F3, from the highest
potentials A, A, to the intermediate potential A*, A. The switch C, is brought
into contact by contacts c, c, with the terminal of feeder F³, by which operation
the feeder to be transferred is brought into connection with the rheostat circuit.
The switch D, is then partly moved so as to close the contacts d³, d, with the
stationary contacts d², d¹², but not far enough to close the contacts d', d. The
rheostat handles e', e, are then moved so as to connect with the proper end of
the transfer rheostat resistance.
It will be found in this case that the alarm bell k, would ring if the switch were
moved to the left, but would not ring if moved to the right which is the correct
position.
The switch S, is then opened disconnecting the feeder from a bus-bar direct at
switch S, but leaving its terminal connected by way of the rheostat, after which
the rheostat handles e', e², are moved to the right.
It will be noticed that the galvanometers G1, G2, will swing back towards zero
as the resistance is gradually increased in the transfer rheostats E', E². When
these galvanometers or voltmeters G1, G2, indicate zero, the condition is such that
the resistance which has been added in circuit with the feeder F³, is sufficient to
cause a drop such that the potential difference at the points where the feeder
connects with the rheostats E, E, is the same as that of the intermediate bus-
bars A³, A. In this condition the switch D', can now be fully closed to the right

page_text: so as to close d', with d', and d, with ds, and the switch S, may now be turned so
as to connect the feeder with the intermediate bus-bars A³, A', or the position
shown for feeder F. The switches D and C6, may now be opened, and the
handles e¹, e, turned to central position leaving the apparatus ready for the next
operation.
The transfer from the bus-bars A3, A4, to the bus-bars A1, A2, is accomplished in
the same manner with the exception that the switch D', is turned to the left
instead of to the right.
Fig. 4, shows a somewhat simplified form of apparatus for practising the
invention, the switch D, being arranged to control the connection of one terminal
only of the rheostats with the bus-bars. The switch serves to shift the rheostats
from A³, to A³, and from A', to A. The connection of the alarm contacts
with A, or with A, is also controlled by means of an ordinary switch attachment
at 45.
The transfer from a lower bus-bar as A1, A2, to an intermediate bus-bar as
A³. A, proceeds as follows:-
Move switch C, to connect the feeder terminal with the rheostats ;-move
switch D2, to the position shown in the drawings, thus connecting the rheostats
with bus-bars A³, A';-move rheostat handles e', in clockwise direction until the
ampere meters give equal readings (if by mistake the attempt should be made to
move the rheostat handle to the left so as to connect the feeder direct to the
highest bus-bar, it is obvious that the alarm would be sounded)--disconnect
feeder by switch S, from bus-bar A¹;-continue movement of the rheostat handles
cutting out resistance in a direction to raise the potential of the feeder terminal
until the voltmeters connected to the middle bus-bars show zero-connect the
feeder to the bus-bars A3, A4, direct by the feeder switch and open switch C, and
restore the arms of the rheostats to position for another operation.
To shift from A³, to A', and from A, to A6, proceed in the same manner
excepting to move switch D2, to the left to connect with the higher bus-
bars A', A.
To shift from a higher to a lower potential bus-bar, connect the terminal of the
feeder to the rheostat by switch C, and move switch D', to connect the rheostat
to the bus-bar to which the feeder is connected by the feeder switch ;-close the
rheostat arms to the left or counter clockwise. Should by mistake the rheostat
handles be moved to the right, it is obvious that the alarm will be sounded, said
alarm being connected by supplemental switches and connections at 45, with one or
the other of the bus-bars of different potential from that which is to be shifted.
This switch 45, also controls the connection of the alarm when the switch D², is in
the opposite direction and the transfer is being made in the manuer first described
in connection with Fig. 4.
The feeder having been connected with the same bus-bar by the rheostat handles
it may be disconnected from said bus-bar by the switch S;-Move the rheostat
arm counter clockwise until the voltmeters indicate the potential of the bus-bar
to which the transfer is to be made.
If the potential indicators be on the intermediate bus-bars and the transfer is to
be made to said bar, it is obvious that they will show zero.
Close the transfer switch of the feeder on the bus-bars of lower potential.
Open switch C, and rheostat arms as before.
Fig. 5, shows the invention applied to one side of the three wire system and in
simpler form. The rheostat in this instance is supposed to be permanently
connected to the bus-bar of highest potential and the switching or changes of
connection necessary under different conditions is obtained by allowing the arm on
the rheostat to close connection in either direction but to stand in normal position
out of circuit with the rheostat itself.
The tension indicator G, may be connected to any bus-bar but preferably to the
middle one.
As before, the indicator G, should be polarized to read in both

page_text: directions if it be connected to the intermediate bus-bar. It will be understood,
however, that it might be connected to any other bus-bar.
The operations would be briefly as follows:-To transfer the feeder from A²,
to A', first switch the feeder terminal by C, to arm E', of the rheostat. This
gives an indication at G, and shows which way the arm el, should be moved ;-
move the rheostat arm to the right clockwise thus closing the connection at the
opposite end of the resistance from that connected at A, through the whole
resistance which should be of proper amount depending upon the maximum
-difference of potential between the bus-bar to which it is permanently connected
and the lowest of the bus-bars which are concerned in any transfer operation ;-
the movement of the rheostat is continued to the right clockwise until the current
indicated at H, equals that indicated at ';-open the feeder transfer switch ;-
continue movement of e', until the indicator G, shows a potential at the feeder
terminal the same as A. This indication would not be " zero when connected
to the middle bus ;-throw the feeder switch S, onto the middle bus-bar A;—
open switch C, and throw arm e', in either direction to open position.
To transfer from A', to A, proceed in the same way.
"
-
To transfer from A, to A, first connect C, to the feeder-move arm e¹,
backward or counter clockwise until it closes the connection at e³, with the bus-
bar A-open feeder switch S,-continue movement of arm e¹, in the same
direction until G, shows proper drop to give a bus-bar potential of A*, on the
feeder switch the feeder by S, onto A* ;-open switch C6, and move arm e',
around the open circuit position or, if desired, move arm e¹, in the same direction
first and then open C.
To shift from A, to A2,-close switch C, on feeder ;-move rheostat handle to
the right thus connecting feeder to A, through the whole resistance and continue
movement clockwise until G, shows potential of A' ;-open switch S, disconnecting
feeder from A*;-move arm el, back or counter clockwise to e³, or to position
where G, will indicate the potential of A2;-close the feeder switch on A²,-
open e', at e, and then open C³.
It will be obvious to electricians that this invention is not confined to continuous
current systems but might be used also in alternating current systems the
character of the rheostats which are employed being properly varied for such
purpose and their inductance, their capacity or impedance being changed by any
of the means known in the art.
By the term "rheostat " I mean to include any device consisting of coils or lengths
of conducting wire, as used ordinarily in the art, to form a resistance without
requiring the mechanical movement of parts as is necessary in the case of an
armature wound with conductors and run as the armature of an electric
.motor.
It will be obvious that a resistance might be similarly connected in permanent
fashion to the middle bus-bar after the manner of the rheostat shown in Fig. 5,
and used for transferring from bar A², to bar A4, while another resistance could be
permanently connected to the higher bus-bar A, and used for transferring
between A, and A. In these instances the resistance would not require to be of
the full capacity of that shown which must be of capacity sufficient for making the
transfer direct from A2, to Aº. When the three resistances are employed, as
described, each might be used as conditions should require. The connection of
additional resistances as that outlined is indicated in the dotted lines. The single
resistance, however, when connected to the bus-bar of highest potential will serve
the purpose of transferring either up or down from any bus-bar to any other, the
resistance being made of proper capacity.
It will be observed that in the case of each of the smaller resistances now
referred to the permanent connection is to the highest of the two bus-bars between
which transfer is to be made.
It will be obvious that, without departing from this invention, other generators

page_text: of electric energy might be used in place of the main dynamo generators supplying
the bus-bars and also that other generators of electro-motive force counter or
assisting might be used in place of the motor or dynamo armatures of
machines C, C¹, C², C³.
Having now particularly described and ascertained the nature of the said inven-.
tion and in what manner the same is to be performed, 1 declare that what I
claim is :-
1. The herein described method of switching a feeder from a source of one
potential to a source of different potential consisting in maintaining the load on the
feeder while gradually changing the potential at a terminal of said feeder until it
is the same as the potential of the source to which the feeder is to be shifted, and
then switching to such source.
2. The herein described method of transferring a feeder from one bus-bar to.
another, consisting in tapping said feeder onto a branch or tap leading from a
source of different potential through a variable resistance, varying the resistance of
said tap or branch until the load indicated on said tap is the same as that indicated
on the feeder, cutting off the feeder connection with its bus-bar, gradually varying-
the resistance until the feeder terminal reaches the bus-bar potential of the bar to
which it is to be transferred and then shifting to said bar.
3. The herein described method of transferring a feeder terminal from a bus-bar
of one potential to a bus-bar of a lower potential consisting in gradually increasing
the resistance in a connection between said feeder and a bus-bar of higher potential
than that to which it is to be shifted, connecting the feeder terminal to the bus-bar
of lower potential and then breaking the connection with the bus-bar of higher
potential.
4. The combination, substantially as described, of a series of bus-bars of graded
potentials, a series of feeders or sets of feeders, switches for shifting said feeders at
pleasure from one bus-bar to another, a potential regulator such as a source of
variable electro-motive force or a variable resistance, and means for varying the
same while connected to a feeder before transfer of said feeder from one bus-bar to
another.
5. In a system of electrical supply, the combination with a series of feeders or
sets of feeders, of a number of sources of different or graded potentials, switches-
for shifting said feeders at pleasure from one bus-bar or source to another, and
means for gradually raising or lowering the potential of any feeder terminal
independently of other feeders or sets of feeders to bring it to the potential of the
bar or source to which it is to be shifted.
6. The combination, substantially as described, of a series of bus-bars of graded
potentials, a series of feeders or sets of feeders, switches for transferring said
feeders from one bus-bar to another, a regulable source of electro-motive force
connected at one terminal to an intermediate potential and provided at its other -
with means for connecting it to any feeder for the transfer operation as described,
and means for reversing the operation of the supplemental source to permit it to.
oppose or aid the said intermediate potential.
7. The combination, substantially as described, of a series of bus-bars, a series
of feeders or sets of feeders, switches for transferring said feeders from one bus-bar.
to another at pleasure, a potential regulator such as a supplemental electro-motive
force generator or a rheostat having means for connecting it to said feeders, a
differential measuring instrument, and means for connecting the two sides thereof
to said regulator and to any feeder simultaneously, as and for the purpose
described.
8. The combination, substantially as described, of a number of sources of different.
or graded potential, a feeder, a switch for shifting said feeder at pleasure from one
source to another, a path or circuit independent of that which connects the feeder
with one of said sources directly, means for connecting the feeder to said independent.
path or circuit while said feeder remains connected directly to said source, and a

page_text: potential regulating device in said independent path for varying the potential at
the terminal thereof which connects to a feeder terminal.
9. The combination, substantially as described, of a series of bus-bars, a bank of
main generators with means for connecting and disconnecting them from said bars,
and an auxiliary or supplemental generator or generators of less capacity provided
with means for placing them in a series circuit between the main generator
supplying one bus-bar and another bus-bar.
10. The combination, substantially as described, of a series of bus-bars of
normally different or graded potentials, a bank of main generators with means for
connecting and disconnecting them severally to and from said bus-bars, and
auxiliary electro-motive force generators coupled together and run part as assisting
and part as counter electro-motive force generators in separate connections
between a main generator or generators and bus-bars of different potential.
11. The combination with the bus-bars of different normal potentials, of dynamo
machines adapted to supply the required different potentials directly, switches for
connecting and disconnecting said machines from said bus-bars, auxiliary armatures
run in connections between bus-bars, and means for making and breaking said
connections, as and for the purpose described.
12. The combination with a series of bus-bars of different or graded potentials,
of supplemental or auxiliary electro-motive force generators in series connections
between said bus-bars and main generators of any desired adjustable or primary
potential capacity, and switches controlling the connections of said generators and
bus-bars, as and for the purpose described, whereby the said graded potentials may
be had according to the loading of the station either from a uniform main potential
source supplemented as described or from a main generator alone when the load
becomes great.
13. The combination of a potential regulator such as an artificial resistance or a
regulable source of electro-motive force connected across the bus-bars, means for
connecting any feeder terminal to either end of said regulator, and means for
breaking the connection of the same end of the regulator with the bus-bar to which
the feeder is connected.
14. The combination, substantially as described, of bus-bars of different or
graded potential, feeder switches for transferring a feeder from one bus-bar to
another, and a galvanometer or voltmeter having one terminal connected to an
intermediate potential and the other to a switch adapted to connect with any
feeder while the same is connected to any bus-bar.
15. The combination, substantially as described, of a number of sources of
different potential, feeders having switches for transferring them from one source
to another, means for controlling the potential at a feeder terminal to raise or
lower the same gradually prior to transfer, and an electric alarm for giving a
signal when the arm of the controller is moved in a direction to connect the feeder
terminal directly with a source of different potential.
16. In an electric light and power central station, the combination with two bus-
bars of the same sign, of an auxiliary generator of electro-motive force counter or
assisting in a direct connection from one bus-bar to the other, and operating in a
series connection between one bus-bar and the source supplying another bus-bar
direct.
Dhin 0th dow of Tul 1901
ALLISON BROS.,
Agents for the Applicant.