INTERMEDIATE DYNAMOS.
Year: 1889

page_text: B. INTERMEDIATE DYNAMOS.
1. The differences in the tersion arising from unequal absorption in the groups can
be decreased, and in a system with any desired number of conductors the equality
(constant proportionality) of the resistances of all groups requisite for keeping the
tension constant can be traced to the equality (proportionality) of the resistances of
two symmetrical groups if as represented in Figs. 1 and 2 one or more intermediate
dynamos are employed which in any manner keep a constant difference in tension at
the point where their distant conductors join the circuit, but which are not con-
nected with each other at the station. The tension of two symmetrical groups (of
equal absorption) is therefore equal to half the difference in the distant tension of
two dynamos.
If, as represented in Fig. 2, the innermost dynamo has to bear the tension of two
groups and if this double group in the distant conductor is again divided in two equal
groups, and provided the resistances of the symmetrical groups are equal the middle
conductor will always be at zero and can therefore consist wholly or partly of earth,
represented by dotted lines in the drawings; one pole of the respective absorber is
connected to earth instead of to the middle conductor.
The equalisation of the resistances of the symmetrical groups of this system is
described under G and the manner of keeping the distant tension of the machines
constant under C.
II. The tension of all the groups can be rendered independent of their absorption
by giving the intermediate dynamos with regard to each other or to the principal
dynamos a difference in tension only equal to the tension of one group and by
connecting the poles of the same denomination of the machines. The intermediate
dynamos can be connected either to one outer conductor Fig. 3 or to one or more of
the inner conductors (Fig. 4) or both cases may be combined as shown in Figs. 5
and 6. Provided again that the distant tension of all dynamos are kept constant, the
tension of any one group will be equal to the difference in tension between the
distant tension of two dynamos or in case of combination the tension of the group
bridged over only by the principal dynamo will be equal to the difference of the
distant tension of the principal dynaino and the sum of the distant tensions of two
intermediate dynamos.
III. The intermediate dynamos may also be connected with each other by their
opposite poles, especially when each intermediate dynamo has only the tension of one
group. The connection with the principal dynamo can in this case be with one
or both of the outer conductors as represented in Fig. 7.
IV. In the arrangements I to III the number of the intermediate dynamos is
always one less than the number of the groups. It may however be also arranged
that in case of a small absorption of current the principal machine is "switched
out" and the installation worked with the intermediate dynamos only, if an additional
intermediate dynamo is provided as represented in Fig. 8 and one of the outer
conductors can be connected by tueans of a switch either with the principal dynamo
or with the additional intermediate dynamo. Lastly the principal dynamo may be
dispensed with altogether and the installation worked with the dynamos heroin-
before referred to as intermediate dynamos, provided again that all the machines
have the same distant tension. Fig. 8. B represents a number of equal machines
connected in series.
C. THE WINDING OF THE DYNAMOS.
The necessary constant distant tension of the machines working together excludes
everywhere the employment of so-called compound dynamos with constant" clamp"
The necessary constant distant tension of the machines working together excludes
everywhere the employment of so-called compound dynamos with constant" clamp"
tension as intermediate dynamous because in the hotter the direction of the current.
must change according to the distribution of the absorption and because their
clamp" tension must be sometimes over and sometimes under the normal tension of

page_text: the groups. For the first mentioned reason this cannot be done by means of
rheostats in the principal circuit, but only machines with variable clamp tension
can be employed, such as double wound dynamos or shunt machines with adjustable
resistance in the shunt circuit, worked eithor by hand or automatically. The following
arrangements are especially adapted for the present purpose for the intermediate as
well as the principal dynamos:
I. In the case B I, simple super-compound machines can be used i.e. double wound
dynamos which have their constant tonsion not at the clamps but at the ends of an
outer resistance here at the points where their distant conductors join the circuit
proper and which only differ from the clamp compound machines in the proportion
of the ampère coils of their windings. It can be proved that the desired effect also
takes place in the distant conductors and the armature when the current is reversed.
Fig. 9 represents a diagram of the winding of a clamp- or super-compound dynamo
provided with a short shunt which latter may however he replaced by a long
shunt. N here refers and also hereaftor to the shunt winding and D to the
direct winding.
A winding here means as also in the following cases the conductor which is wound
on the machine through the length of which conductor flows a current of equal
intensity it being immaterial whether the conductor is wound round one or more
arms of the magnet or whether it starts from one or both dynamo- or brush-clamps.
It is also to be considered as a single winding when two windings are employed the
intensities of the currents of which are constantly proportional to each other. Separate
windings are only considered those which according to the construction or connection
of the machines carry or can carry different intensities of current. By the term
"shunt" can be understood tho connection between the brushes or between one
brush and one end of the direct winding or between both ends of the direct
winding.
II. As soon as more than one conductor emanates from one dynamo or as mentioned
above under B II, B III, the saine or opposite poles of the dynamos are connected,
the constant distant tension cannot be obtained by two windings only, but in this
case a third or fourth winding is requisite according to whether only one or both of
the dynamo clamps are provided with conductors or connections. Besides the shunt
and the so-called direct winding which represents here the armature current (but does
not carry the latter) one or also the other distant conductor will be carried round the
arms of the magnet and that in such a manner that all the windings magnetise in the
same sense with a norinal direction of the current. It can be proved with proper
calculation or measurement that in this case the distant tension remains constant also
no matter what quantity of current is fed to or abstracted from the machine by the
conductors and independent of the direction of the current passing through the
distant conductors and the armature. The diagram of the winding of a triple- or
quadruple-compound dynamo is represented in Figs. 98 and 9 y The. lines L
represent the conductors or connections. The windings carrying the distant conductor
current are marked F and f.
III. When connecting the same or opposite poles of triple or quadruple compound
dynamos the machines as can easily be seen must be (at least) connected together at
two points. The distant windings can in this case be arranged either for quantity
or tension but this of course necessitates a respective alteration in the dimensions of
the windings. If the distant windings are connected in multiple arc the distribution
of intensity of the current can be chosen according to demand, which is of great
importance to produce practical winding proportions especially when two or more
machines of unequal diinensions are connected together with their poles of the same
denomination.
Fig. 10 for instance represents a diagram of the arrangement of an installation with
five conductors, as also does Fig. 8 a without reserve machine, in which are shown the
different connections. The distant windings are here arranged in multiple arc where
the poles of the same denominations are connected together, and once arranged in

page_text: I. In connecting the same poles of triple or quadruple compound dynainos the
clamp tension of the two or inore machines must be increased by the same amount,
whilst if the opposite poles are connected together the clamp tension of one machine
must be decreased in proportion as the tension of the other is increased. In the first
instance the difference between the tensions of the two machines will remain the saine
and in the second instance the suin of the tensions. This points to the employment
of clamp compound dynamos by obtaining the necessaryadditional electromotive force
from a separate inachine included or switched in the distant conductor. To keep in
this auxiliary machine constant proportionality between the intensity and the tension
of the current, the machine must be constructed as a principal dynamo and must
revolve with a uniform speed.
II. If such an auxiliary dynamo is switched into a distant conductor common to
several (or only two) dynamos, all multiple compound machines will be brought back
to super-compound machines, as represented in one instance in Fig. 12 a. If auxiliary
machines are "switched-in" in both outer conductors as shown in Figure 12, the
principal machine is converted into a common clamp compound dynamo,which permits
the connection of several distant conductors to the same principal dynamo without
using compensating conductors and to work the principal machine with a variable
average tension. If lastly auxiliary machines are switched into all conductors, the
intermediate dynamos will also become compound dynamos and all distant conductors
anay be common which are then separately served by the auxiliary instead of the inter-
inediate dynamos. Fig. 13 a represents an example of the last mentioned arrangement.
Fig. 13 B shows how the constant tension in the groups can be maintained by means
of the employment of auxiliary machines in case the installation is only worked by
means of clamp compound machines connected in series.
III. In the intermediate machines, provided a shunt is employed the direction of
the current will change in the armature but not in the shunt, which will therefore
retain the magnetism of the arms to a certain average point. With correct calculation
and suitable condition of the material the amount of "hysteresis" in this vicinity is
so small that the machine can accommodate itself to the differences of absorption in the
quickest possible inanner. In the auxiliary dynamos however the magnetism of the
arms must pass beyond zero in case the direction of the current is reversed it must
therefore pass the point of the greatest "hysteresis" in consequence of which the
regulating effect of the machine will be deteriorated. If however as represented in
diagram in Figure 14, the auxiliary dynamo is provided with a subordinate shunt
winding N acting in an opposite direction to the direct winding the magnetism will,
after the cessation of the distant current A B, be brought to zero even before the
direction of the current is reversed.

page_text: The second method mentioned under A for the regulation of a system with
multiple conductors and unequal absorption in the groups, is to maintain the
equilibrium between the groups themselves instead of altering the electromotive
power. This can be done in the following manner :
I. According to the conditions a smaller or greater part of all the current
absorbers are not connected rigidly with one group but are so arranged that they
may be "switched" into one of the other groups the absorption of which for tho time
being is smallor, and this switching is effected automatically and instantaneously by
group switch."
፡፡
The group switch consists of a differential tension relay the opposing electro-
magnets or solenoids of which are provided with current from the respective groups,
and of two "working electromagnets" the opposite poles of which are arranged
facing each other and through the coils of which passes a current in one or the
other direction according to the deviation of the norinal position of the armature
of the relay, so that a permanent magnet situated between these two magnets is
attracted strongly in one or the other direction and remains until the poles are
again changed.
1
The construction of the switch in detail may be of any desirable form, but it
must be so arranged that the permanent magnet always connects the lamp con-
ductor suitably attached to it with that one of the groups the tension of which
acts on the relay, which has the least absorption i.e. the higher tension. To obtain
an instantaneous switching and a good contact the "group switch may be com-
bined with a momentum switch by having the switching done indirectly by the switch
magnets and letting the latter act on a spring or other power which would effect
the switching.
33
II. A similar effect to that of the group switch, only with greater loss of energy
can be obtained by an automatic "switching-in" of substitute resistances, if these
latter are not as usual combined in sets (rheostats) but are distributed in the circuit
equally amongst the different groups, the same as the current absorbers. Each
resistance is provided with a separate tension relay the armature of which switches it
in as soon as the tension of the group has attained a certain height and this may be
effected in any desired manner and on any principle. The effect of this arrangement
is as instantanecus as that of the "group switch" and the distribution of these
apparatuses on the one or other construction among the absorbers ensures the greatest
security against damaging the lamps by burning etc., even if one of the apparatuses
should fail to act, as it would be replaced at once by the one next in the proportion of
absorption or tension.
III. The effectiveness of the before described apparatuses is dependent on their
sensitiveness, and the latter inay be increased and regulated by making the oscillation

page_text: or deviation of the relay armature adjustable in reference to the magnetic field
(distance of the armature from the pole) or by making the power acting on the
armature adjustable, so that it may be adjusted per fraction of the oscillation (about
per millimetre). It can be best proved graphically that the moment of the closing
the circuit by the relay can be exactly adjusted by the relay by means of one of these
arrangements, and that the sensitiveness of the relay can be finely adjusted when one
of these two arrangements is used in combination with the usual adjustability of the
distance of the contacts from the pendulum or armature.
The opposing power of the armature or pendulum can be adjusted as regards the
deviation or oscillation, in a spring actuated armature by adjusting the acting length
of the spring (flat or spiral) and in a weighted pendulum armature by adjusting the
effective length of the pendulum or the effective weight of the penduluin.
"
IV. The group switch" is employed by using or distributing and connecting
certain absorbers (switch lamps) for instance with groups 1 and 2, others with
groups 3 and 2, others again with groups 4 and 3, so that they may be switched in
and out of the respective groups. When the machines are connected however as
described under BI the switch lamps must be arranged between symmetrical groups.
The "group switch" only operates when the tension of the current is unequal and
will not be employed much if the tension of the groups is kept constant by any other
means as for instance in the arrangements B II or B III. The "group switches
will serve in this instance to remedy other irregularities which may occasionally occur
in an otherwise well regulated installation, such as when a dynamo becomes heated or
short circuited, or to remedy inequalities which may occur in points of the circuit
which are distant from the connecting points of the distant conductors which latter
points are always kept at the same potential. The same refers to the single or separate
replacing resistances. When both arrangements are employed in combination and
the coarser adjustment left to the group switches and the finer to the single or
separate resistances, which can be done by the above described adjustability of the
sensitiveness, an equal tension in the groups can be obtained throughout with a
minimum loss of energy.
H. ARRANGEMENT OF THE CURRENT ABSORBERS.
The multiple conductor system described in A I requires an equal distribution of
the absorbers in the groups, the arrangement B I only requires equal resistances in
symmetrical groups, all other above described arrangements permit of any desired
distribution, which only affects the work which the separate machines have to do. If
the absorbers are not distributed equally but only symmetrically, and that in such a
manner that the outermost groups have the least absorption and each next inner
group has 1/n more of current absorbers than the next outer one, then each inner
conductor has to carry 1/ of the current of the outer conductor. If in consequence
of the local conditions the proper loss of tension takes place in the outer conductors
with full (or average) absorption, then the inner conductors are also used properly
if n is chosen equal to the proportion of the sectional surface of the outer and inner
conductors, whilst with equally distributed work the inner conductors remain unused
(wholly in the distant conductors and partly in the absorber circuit) and only serve
for compensating purposes when the absorption is unequal. The size of the driving
machine is calculated according to the distribution of the absorbers, on easily
recognisable principles.
For a certain amount of current the weight of the copper conductors can be
reduced by a proper distribution; for instance in an installation with six conductors
the inner conductors of which are of a section of that of the outer conductors
(therefore n = 5) and in which the absorbers are distributed in the proportion
of 5:6:7:6:5, the sectional area of copper will be reduced to . The saving
in this instance therefore amounts to 10.7 %.
II. As with a view to economy generally the tension of the groups is made as high
as possible, it is necessary sometimes to transform the current for absorbers of low

page_text: tension or to connect several absorbers in series close to one another, for instance with
a tension of 100 to 120 volts in the groups to connect the arc lamps in pairs, or to
work with resistancos.
This disadvantage can be avoided in installations with multiple conductors if one
(or more) groups of lower tension for are lamps and small electromotors say from 55
to 65 volts are employed. This can be done in all cases represented in Figs. 3 to 7
if a somewhat lower tension is given to the principal dynamo so that it only receives
the desired expansion from this overbridged group, it can in all cases however also
be done by means of an intermediate dynamo of less volts. In the cases represented
in Figs. 1 and 2 either the middle group or a couple of symmetrical groups may be
constructed of less volts.
1000''
Dnd this 10th stamhan 1000
Distribution of the Electric Current and the Current Absorbers in
Installations with Multiple Conductors..
J, WALDEMAR MEISSNER of Konigsberg in the Kingdom of Prussia, Engineer
do hereby declare the nature of this invention and in what manner the same
is to be perforined to be particularly described and ascertained in and by the
following statement:—
A. GENERAL PRINCIPLE.
To decrease the cost of electric installations in which the absorbers are at a
distance from the machines a mixed arrangement of the lamps or other current
absorbers is employed by arranging then in a number of equal groups and joining the
absorbers of each group in multiple are while the groups theinselves are joined in
series by ineans of interinediate conductors.
This arrangement may generally be called a system of multiple conductors, whether
the electro-motive force is used
1, only between the outer conductors or
2, only between two conductors situated next to each other, or
3, between the outer conductors and also between any two conductors situated next
to each other or
4, between the outer conductors and also between any two conductors situated next
to each other or not or
5, parallel to the groups as well as in some or all of the conductors,
And whether the distant conductors which carry the current from the station are
composed of outer conductors only or outer and inner conductors.
The latter is always the case in the arrangement 2, and also in 5, the former
always in 1; in the arrangements 3 and 4 the distant conductors may have inner
conductors or not.
The arrangements 4 and 5 have hitherto not been used or proposed and the
arrangement 3 only with accumulators as intermediate electro-motive forces.
To the advantages of the multiple conductor system is opposed the difficulty of
keeping the tension constant in the different groups when the absorption of the
current is unequal or varying in them, i.e. to provide each absorber with a normal
current. It can be proved by calculation that this cannot be attained by variable
resistances arranged in the distant conductors, neither in general nor in the arrange.
ment 2, in the case that the sum of the resistances of the distant.conductors is not
SiBall enough in comparison with the resistances of the groups, i.e. that the installation
works with a considerable loss of tension. By using the arrangement 3 with
accumulators only small differences in the tension can be compensated as the
clamp" "tension of the battery decreases when the intensity of the; current
increases.
“

page_text: The arrangements described herein havo for their object to keep the tension
constant in the different groups at all events mentioned above when the absorption of
the current is varying and this is attained by using in addition to the principal
dynamo between the onter conductors or, if necessary several principal dynamos
joined in multiple arc, intermediate or auxiliary dynamos which keep the inner
conductors on a constant potential although the absorption in the different groups may
vary, or by regulating the absorption in the groups themselves, or by using these two
means in combination. By a peculiar division of the current absorbers into groups
advantages are also obtained as regards economy in the conductors and the working of
the installation. Wherever in this Specification reference is made to drawings it is to
those filed with my Provisional Specification.
B. INTERMEDIATE DYNAMOS.
I. The differences in the tension arising from unequal absorption in the groups can
be decreased, and in a system with any desired number of conductors the equality
(constant proportionality) of the resistances of all groups requisite for keeping
the tension constant can be traced to the equality (proportionality) of the resistances
of two and two symmetrical groups if as represented in Figs. 1 and 2 one or more
intermediate dynamos are employed which in any manner keep a constant difference
in tension at the point where their distant conductors join the circuit but which are
not connected with each other at the station. The tension of two syinmetrical groups
(of equal absorption) is therefore equal to half the difference in the distant tension of
two dynamos.
If, as represented in Fig. 2, the innermost dynamo has to bear the tension of two
groups and if this double group in the distant conductor is again divided in two equal
groups in the circuit and provided the resistances of the symmetrical groups are equal
the middle conductor will always be at zero and can therefore consist wholly or partly
of earth, represented by dotted lines in the drawings; one pole of the respective
absorber is connected to earth instead of to the middle conductor.
The equalisation of the resistances of the symmetrical groups of this system is
described under G and the manner of keeping the distant tension of the machines
constant under C.
11. The tension of all the groups can be rendered independent of their absorption
by giving the intermediate dynamos with regard to each other or to the principal
dynamos a difference in tension only equal to the tension of one group and by con-
necting the poles of the same denomination of the machines. The intermediate
dynamos can be connected either to one outer conductor Fig. 3 or to one or more of
the inner conductors (Fig. 4) or both cases may be combined as shown in Figs. 5 and 6.
Provided again that the distant tension of all dynamos is kept constant, the tension of
any one group will be equal to the difference in tension between the distant tension
of two dynamos or in case of combination the tension of the group bridged over only.
by the principal dynamo will be equal to the difference of the distant tension of the
principal dynaino and the sum of the distant tensions of two intermediate dynamos.
III. The intermediate dynamos may also be connected with each other by their
opposite poles, especially when each intermediate dynamo has only the tension of one
group. The connection with the principal dynamo can in this case be with one or
both of the outer conductors as represented in Fig. 7.
IV. In the arrangements I to III the number of the intermediate dynamos is always
one less than the number of the groups. It may however be also arranged that in
case of a small absorption of current the principal machine is "switched out"
and the installation worked with the interinediate dynamos only, if an additional
intermediate dynamo is provided as represented in Fig. 8 a and one of the outer
conductors can be connected by means of a switch either with the principal dynaino
or with the additional intermediate dynamo. Lastly the principal dynamo may be
dispensed with altogether and the installation worked with the dynamos hereinbefore
referred to as intermediate dynamos, provided again that all the machines have the

page_text: same distant tension,
in series,
represents a number of equal machines connected
C. THE WINDING OF THE DYNAMOS.
The necessary constant distant tension of the machines working together excludes
everywhere the employment. of so-called compound dynamos with constant "clamp
tension as intermediate dynamos because in the latter the direction of the current
must change according to the distribution of the absorption and because their "clamp"
tension must be sometimes over and sometimes under the normal tension of thegroups
For the first mentioned reason this cannot be done by means of rheostats in the
principal circuit, but only machines with variable clamp tension can be employed,
such as double wound dynamos or shunt machines with adjustable resistance in the
shunt circuit, worked either by hand or automatically. The following arrangements
are especially adapted for the present purpose for the intermediate as well as the
principal dynamos:
I. In the case B I, simple super-compound machines can be used i.e. double wound
dynamos. which have their constant tension not at the clamps but at the ends of an
outer resistance at the points where their distant conductors join the circuit proper
and which only differ from the clamp compound machines in the proportion of the
ampère coils of their windings. It can be proved that the desired effect also takes
place in the distant conductors and the armature when the current is reversed.
Fig. 9 a represents a diagram of the winding of a clamp- or super-compound dynamo
provided with a short shunt which latter may however be replaced by a long shunt.
N here refers and also hereafter to the shunt winding and D to the direct. winding.
A winding here means as also in the following cases the conductor which is wound
on the machine through the length of which conductor flows a current of equal
intensity it being immaterial whether the conductor is wound round one or morearms
of the magnet or whether it starts from one or both dynamo- or brush-clamps. It
is also to be considered as a single winding when two windings are employed the
intensities of the currents of which are constantly proportional to each other. Separate
windings are only considered those which according to the construction or connection
of the machines carry or can carry different intensities of current. By the term
"shunt" can be understood the connection between the brushes or between one brush.
and one end of the direct winding or between both ends of the direct winding.
II. As soon as more than one conductoremanates from one dynamo or as mentioned
above under B II, B III, the same or opposite poles of the dynamos are connected, the
constant distant tension cannot be obtained by two windings only, but in this case a
third or fourth winding is requisite according to whether only one or both of the
dynamo clamps are provided with conductors or connections. Besides the shunt and
the so-called direct winding which represents here the armature current (but does not
carry the latter) one or also the other distant conductor will be carried round the
arms of the magnet and that in such a manner that all the windings magnetise in the
same sense with a normal direction of the current. It can be proved with proper
calculation or measurement that in this case the distant tension remains constant also
no matter what quantity of current is fed to or abstracted from the machine by
the conductors and independent of the direction of the current passing through the
distant conductors and the armature. The diagram of the winding of a triple- or
quadruple-compound dynamo is represented in Figs. 9 B and 9 y. The lines L repre-
sent the conductors or connections.
The windings carrying the distant conductor
current are marked F and f.
III. When connecting the same or opposito poles of triple or quadruple compound
dynamos the machines as can easily be seen must be (at least) connected together at
two points. The distant windings can in this case be arranged either for quantity or
tension but this of course necessitates a respective alteration in the dimensions of the
windings. If the distant windings are connected in multiple are the distribution
of intensity of the current can be chosen according to demand, which is of great
¡mportance to produce practical winding proportions especially when two or more

page_text: nive conductors, as also does Fig. 8 a without reserve machine, in which are shown the
different connections. The distinct windings are here arranged in multiple are where
the poles of the same denominations are connected together, and once arranged in
multiple arc and once in series where the opposite poles are connected together. In
case an additional or reserve intermediate dynamo is "switched-in" instead of the
principal dynamo, a switch arrangement on one of the known principles may be
employed for the contact points of the machines, which arrangement may be (either
with or without safety arrangement) for gradual switching by means of a rheostat or
for sudden switching by means of a double momentum switch.
D. DOUBLE CONDUCTORS.
In all the cases Figs. 3 to 8 the triple or quadruple winding of the machines can be
replaced by a double winding for super-compounding if the machines are not con-
nected together at the station but only in the circuit, and for this purpose a separate
conductor leads from each machine pole to the respective joining points of the circuit.
Fig. 11 represents for instance the employment of a double conductor as used with the
simplest form of a triple conductor system such as represented in Fig. 3 a.
E. AUXILIARY DYNAMOS.
I. In connecting the same poles of triple or quadruple compound dynamos the
clamp tension of the two or more machines must be increased by the saine amount,
whilst if the opposite poles are connected together the clamp tension of one machine
must be decreased in proportion as the tension of the other is increased. In the first
instance the difference between the tensions of the two machines will remain the same
and in the second instance the sum of the tensions. This points to the employment of
clamp compound dynamos by obtaining the necessary additional electromotive force
from a separate machine included or switched in the distant conductor. To keep in
this auxiliary machine constant proportionality between the intensity and the tension
of the current, the machine must be constructed as a principal dynamo and must
revolve with a uniform speed.
II. If such an auxiliary dynamo is switched into a distant conductor common to
several (or only two) dynamos, all multiple compound machines will be brought back
to super-compound machines, as represented in one instance in Fig. 12a. If auxiliary
machines are "switched-in" in both outer conductors as shown in Fig. 12, the
principal machine is converted into a common clamp compound dynamo, which
permits the connection of several distant conductors to the same principal dynamo
without using compensating conductors and to work the principal machine with a
variable average tension. If lastly auxiliary machines are switched into all conductors,
the intermediate dynamos will also become compound dynamos and all distant con-
ductors may be common which are then separately served by the auxiliary instead of
the intermediate dynamos. Fig. 13 a represents an example of the last mentioned
arrangement. Fig. 13 B shows how the constant tension in the groups can be
maintained by means of the employment of auxiliary machines in case the installation
is only worked by means of clamp compound machines connected in series.
III. In the intermediate machines, provided a shunt is employed the direction of
the current will change in the armature but not in the shunt, which will therefore
retain the magnetism of the arms to a certain average point. With correct calcula-
tion and suitable condition of the material the amount of "hysteresis" in this
vicinity is so small that the machine can accommodate itself to the difference of
absorption in the quickest possible manner. In the auxiliary dynamos however the
magnetism of the arms must pass beyond zero is case the direction of the current is
reversed it must therefore pass the point of the greatest "hysteresis" in consequence

page_text: The second method mentioned under A for the regulation of a system with multiple
conductors and unequal absorption in the groups, is to maintain the equilibrium
between the groups themselves instead of altering the electromotive power. This can
be done in the following manner :-
I. According to the conditions a smaller or greater part of all the current absorbers
are not connected rigidly with one group but are so arranged that they may be
"switched" into one of the other groups the absorption of which for the time being
is smaller, and this switching is effected automatically and instantaneously by n
"group switch."
"
The group switch consists of a differential tension relay the opposing electro-
magnets or solenoids of which are provided with current from the respective groups,
and of two working electro-magnets" the opposite poles of which are arranged
facing each other and through the coils of which passes a current in one or the
other direction according to the deviation of the normal position of the arinature
of the relay, so that a permanent magnet situated between these two magnets is
attracted strongly in one or the other direction and remains until the poles are
again changed.
The construction of the switch in detail may be of any desirable form, but it must
be so arranged that the permanent magnet always connects the lamp conductor
suitably attached to it with that one of the groups the tension of which acts on the
relay, which has the least absorption i.e. the higher tension. To obtain an instan-
taneous switching and a good contact the "group switch" may be combined with a
momentum switch by having the switching done indirectly by the switch magnets
and letting the latter act on a spring or other power which would effect the
switching.
•
A view of the method of action of a group-switch of the kind in question is best
obtained by reference to an outline drawing such as is shown at Fig. 15. This
represents the inost simple and at the same time most effective form of the group
switch by means of which a change of pole of the lamps connected in the circuit is
avoided a point which is essential in the case of are lamps. It is true that the
drawing differs from the arrangement above indicated by having the magnet (8) not
in the literal sense between the two electro-magnets (M and M') but rather is
movable above them after the manner of the arm of a balance. Likewise the two
electro-magnets do not have the same poles literally turned towards one another, but
have the poles of the same name pointing in the saine direction, namely towards the
"

page_text: steel magnet. What has been said above takes place also in the present case when
the magnetic circuit is takon into consideration. Within this circuit the steel
magnet is situated "between "the two electro-inagnets which have their poles of the
same sign turned towards one another. The alteration which has been effected in the
external arrangement has merely been introduced for the sake of economizing space
when practically carrying out the invention without in any way altering the method
of action which is as follows:-
The coils, which are connected in series, of the electro-magnets M. and M', excite
the samne polarity at the upper ends of the lattor as soon as the current begins to pass,
P and P' being thus for example south poles; the two poles and s of the steel
magnet which turns upon a horizontal axis are turned in the same direction ¿e. with
redoubled energy being attracted and s repelled and the steel magnet brought
into the position shown in the drawing. On reversing the current n is repelled and s
attracted the steel magnet immediately assuming the opposite position inclining to
the right.
In order to apply this movement to switching the lamps in or out the disc S
consisting of insulating material is attached to ns-the cylindrical surface of the
dise being provided with three contact pieces, the centre one of which is connected
with the clamp II by means of a radial arin and a contact ring and contact spring,
the other two being connected with clamps I and II by incans of contact springs.
It is at these three clamps however that the three adjacent conductors of the system
enter the apparatus while the + and conductors which pass to the lamp to be
switched in are connected as may be seen from the drawing with binding screws. It
may be seen at once from the drawing that the lamp connections are connected with
the system of conductors (or clamps) I and II whenever the steel magnet bappens to
be in the position shown in the drawing; but the connection is with the systems Il
and III on the other hand when the steel magnet is inclined to the right. Reversing
the current in the coils of the electro-magnets thus occasions the switching in of one
group of lamps and the switching out of the other.
The electro-magnets are excited by the differential tension relay situated over the
-above described (automatic) switch. This relay consists of the two separate high
resistance coils R and R and the soft iron armature a suspended between them or
their cores. As shown by the drawing R is permanently connected with the
conductors I and II and R with conductors II and III; the armature a however
forms the terminal of the circuit which begins at the clamp II and which excites the
working electro-magnets Mand M'; this circuit consequently is not closed so long as
a remains in the middle between R and R' that is to say so long as the two relay
coils are excited with equal intensity. If however the tension in one of the groups
rises one of the relay coils becomes more strongly excited than the other, and so the
former attracts the arinature; by this means however the above mentioned circuit is
closed as the armature is provided underneath with a contact piece which in this case
comes to touch one or other of the contacts connected with the clamps I or III shown
in the drawing underneath the relay coils. If now as inust be assumed the arrange-
ment of the connections is such that the tensions in the conductors of the series I II III
rise or fall-II having the medium tension, it follows that the current starting from II
and passing through the electro-magnets must have the opposite direction according
as it flows through the armature of the relay to the clamp I or to the clamp III.
Each movement of the relay pendulum thus causes the current to flow through the
electro magnets in opposite directions and consequently effects the switching in of the
lamps in the one group or the other.
Spaces are shown at P and P¹ in the drawing for receiving the poles n and s—an
arrangement which has the effect of increasing the magnetic action as much as
possible. The switching in and out of the different groups of lamps takes place in
this manner with such rapidity that the breaking of the current is practically
unnoticeable and thus the employinent of an instantaneous switch as inentioned in the
Specification is hardly any longer necessary.
'
II. A similar effect to that of the group switch, only with greater, loss of energy

page_text: can be obtained by an automatic "switching-in" of substitute resistances, if these
latter are not as usual combined in sets (rheostats) but are distributed in the circuit
equally amongst the different groups, the same as the current absorbers. Each
resistance is provided with a separate tension relay the armature of which switches it
in as soon as the tension of the group has attained a certain height and this may be
effected in any desired manner and on any principle. The effect of this arrangement
is as instantaneous as that of the "group switch" and the distribution of those
apparatuses on the one or other construction among the absorbers ensures the
greatest security against damaging the lamps by burning etc., even if one of the
apparatuses should fail to act, as it would be replaced at once by the one next in
the proportion of absorption or tonsion.
III. To increase the sensitiveness of the group-switch two different kinds of
apparatus may be employed. To alter the position of the relay armature in reference
to the magnetic field, the armature must be capable of being removed from or
approached to the coils or to their iron cores. In the case of the differential relay
with two separate coils the alteration of position must take place with exact regularity
with regard to both the coils. This is best effected in the usual way by making the
bodies (arms) of the relay magnets movable in the direction of the vibrations of the
pendulum along a screw spindle provided with a left handed thread at one end and a
right-handed thread at the other; by turning the spindle both coils may be equally
approached to or removed from the armature.
Fig. 15 represents a second possible form of carrying out the idea. The position
of the relay armature to the inagnetic fields is the same as before, on the other hand
the force acting against the magnetismn is variable in regard to its number of units,
and it hence follows that the simplest method of exercising opposing force is by means
of a flat spring from which the relay armature may be suspended as is here done and
pre-supposed in the drawing. The spring is rigidly attached at its upper end and
supported somewhat lower down by two edges-these edges, as indicated in the
drawing by means of arrows, being movable vertically, an end attained by causing
them to be attached to a slide rod (or piece) which can be moved up or down between
guides (with the assistance of a screw). If the flat spring be chosen of such thinness
that its effect may be neglected while the armature (or the mass connected with it) is
of considerable weight this weight may be used as counterpoise to the magnetic
attraction. The arrangement just described may serve to alter the length of the
pendulum as also to regulate the effective length of spring. Finally the same end
may be attained by attaching in the usual way to the relay-spindle above or below the
point of suspension a vertical screw spindle provided with a heavy nut. The regulating
is effecting by screwing the latter up or down.
In all cases as already pointed out it is indispensable that the distance between
the two relay-contacts connected with the clamps II and III should be alterable-
as is usually done; two screw-points protected by platinum are the simplest and best
for the contacts, and by turning then the points of contact can be approached to or
removed from the pendulum.
IV. The "group switch" is employed by using or distributing and connecting
certain absorbers (switch lamps) for instance with groups 1 and 2, others with
groups 3 and 2 others again with groups 4 and 3, so that they may be switched in
and out of their respective groups. When the machines are connected however as
described under BI the switch lainps must be arranged between symmetrical groups.
The group switch" only operates when the tension of the current is unequal and
will not be employed much if the tension of the groups is kept constant by any other
means as for instance in the arrangements B II or III. The group switches."
will serve in this instance to remedy other irregularities which may occasionally occur
in an otherwise well regulated installation, such as when a dynamo becomes heated or
short circuited, or to remedy inequalities which may occur in points of the circuit
which are distant from the connecting points of the distant conductors which latter
points are always kept at the same potential. The same refers to the single or

page_text: separate replacing resistances. When both arrangements are employed in com-
bination and the coarser adjustinent left to the group switches and the finer to the
single or separate resistances, which can be done by the above described adjustability
of the sensitiveness, an equal tension in the groups can be obtained throughout with
a minimum loss of energy.
H. ARRANGEMENTS OF THE CURRENT ABSORBERS.
The multiple conductor system described in AI requires an equal distribution of
the absorbers in the groups, the arrangement B I only requires equal resistances in
syninetrical groups, all other above described arrangements pernit of any desired
distribution, which only affects the work which the separate machines have to do. If
the absorbers are not distributed equally but only syminetrically and that in such a
manner that the outermost groups have the least absorption and each next inner group
has 1/n noro of current absorbers than the next outer one, then each inner conductor
has to carry 1/n of the current of the outer conductor. If in consequence of the local
conditions the proper loss of tension takes place in the outer conductors with full (or
average) absorption, then the inner conductors are also used properly if n is chose
equal to the proportion of the sectional surface of the outer and inner. conductors,
whilst with equally distributed work the inner conductors remain unused (wholly in
the distant conductors and partly in the absorber circuit) and only serve for com-
pensating purposes when the absorption is unequal. The size of the driving machine
is calculated according to the distribution of the absorbers, on easily recognisable
principles.
=
For a certain amount of current the weight of the copper conductors can be reduced
by a proper distribution; for instance in an installation with six conductors the inner
conductors of which are of a section of that of the outer conductors (therefore n 5)
and in which the absorbers are distributed in the proportion of 5:6:7:6:5, the
sectional area of copper will be reduced to 3. The saving in this instance therefore
amounts to 10.7%.
II. As with a view to economy generally the tension of the groups is made as high
as possible, it is necessary sometimes to transform the current for absorbers of low
tension or to connect several absorbers in series close to one another, for instance with
a tension of 100 to 120 volts in the groups to connect the are lamps in pairs, or to
work with resistances.
This disadvantage can be avoided in installations with multiple conductors if one
(or more) groups of lower tension for arc lamps and small electro-motors say from 55
to 65 volts are employed. This can be done in all cases represented in Figs. 3 to 7 if
a somewhat lower tension is given to the principal dynamo so that it only receives
the desired expansion from this overbridged group, it can in all cases however also
be done by means of an intermediate dynamo of less volts. In the cases represented
in Figs. 1 and 2 either the middle group or a couple of symmetrical groups may be
constructed of less volts.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
-:
1. In a multiple conductor installation such as described under A the employment
of one principal dynamo (or more connected in multiple arc) between the outer con-
ductors, in combination with one or more intermediate dynamos of less volts, as
also the arrangement of the machines and their connection with the same er opposite
poles substantially as described and represented in diagrams 1 to 7, 8 and 11 of the
accompanying drawings.
2. The employment of super-compound dynamos for multiple conductor installations
substantially as described.
3. In a dynamo machine to which two or more distant conductors are connected

page_text: and which either is provided with foeders or is connected with one or more other
dynamos at the same or opposite poles the employment besides a so-called short or
long shunt and a direct winding, of a third and fourth winding on the arms of the
magnet, which each carry the current of a distant conductor or an equivalent part
thereof, and which act magnetising in the circuit of the machine in the same direction
as the direct and the shunt winding substantially as described.
4. The employment of inultiple compound machines described above, for multiple
conductor installation and their connection with distant conductors arranged in series
or in multiple arc, at the saine or opposite poles substantially as described.
5. In an electric conductor especially in an outer or inner conductor of a multiple
conductor installation, the employment of an auxiliary dynamo revolving at a
constant speed, for the purpose of keeping two points of the circuit at an equal
potential irrespective of the direction of the current in the said circuit substantially
as described.
6. In a dynamo machine such as described above the employment of a short or
long shunt in addition to the direct winding and acting opposite to the latter
(differential winding) for the purpose of facilitating the reversal of the magnetism
in the arms substantially as described.
7. At or in the vicinity of the absorbers of a multiple conductor installation the
employment of automatic switch arrangements (group switches) which by the aid of
differential tension relays switch some of the absorbers from a group having too
great an absorption to one having less substantially as described.
8. At or in the vicinity of the absorbers of a multiple conductor installation the
employment of single replacing resistances which by means of a tension relay are
switched into a group having too little absorption and switched out again when the
tension decreases or switched into a group having less absorption substantially as
described.
9. In a relay for the purpose of regulating the sensitiveness thereof, the arrange-
ment by which as well as the contacts to be touched by the armature, either the
distance of the relay-magnet or solenoid (or in differential relays with two magnets
or solenoids the distance of both) from the arinature or the force opposed to the
magnetism per fraction of this oscillation is rendered adjustable, or all three of these
adjustables may be employed in combination substantially as described.
10. In a multiple conductor installation the unequal distribution of the current
absorbers in the groups in the manner described under H I for the purpose of also
utilising the inner conductors for the conveyance of the current when the absorption
is normal substantially as described.
11. In a multiple conductor installation the employment of secondary dynamos
for driving or exciting the intermediate dynamos described in claim 1 substantially as
set forth.
Dated this 10th dor of Luna 1800
W. P. THOMPSON & BOULT,
Agents for the Applicant.