Improvements in Electrical Distributing Apparatus.
Year: 1892

page_text: Date of Application, 14th Apr., 1892
Complete Specification Left, 14th Jan., 1893-Accepted, 18th Feb., 1893
PROVISIONAL SPECIFICATION.
Improvements in Electrical Distributing Apparatus.
We, ROOKES EVELYN BELL CROMPTON of the Arc Works, Chelmsford, in the
County of Essex, and WILLIAM ASHCOMBE CHAMEN of Crowley, Baker Road,
Harlesden, in the County of Middlesex, Electrical Engineers do hereby declare
the nature of this invention to be as follows:-
The object of our invention is to overcome the difficulties found in the application
of electrical accumulators or secondary batteries for the purposes of supplementing
a supply of electrical energy whether they be used as reservoirs, or partially
as regulators, or as a safeguard against temporary breaksdown. It has always been
the desire of those using accumulators in this connection to connect them to the
system in such a manner that the generating machinery can be kept working at a
more constant load by charging the accumulators at times when the demand is
small and allowing them to discharge so as to reinforce the supply from the
generating machines at times when the demand is great.
One of the chief difficulties in such application is the very great difference
between the "charging" E.M.F. or pressure required to charge a fixed number of
such accumulators up to such a degree of complete charge as is found in practice is
necessary to maintain them in good condition, and the "discharging" E.M.F. or
pressure of the same cells when discharging at the required rate. To give actual
figures if we take the well known lead couple in sulphuric acid accumulator
originally invented by Planté we find that whereas the charging E.M.F. per cell
may frequently rise to 2.5 volts the available E.M.F. or pressure of the same cell
when discharging at its maximum rate may not exceed 1.8 volts or a total difference
of 400/9 In the past this difficulty has been got over by varying the number of
charged, and to which they in turn are intended to furnish the whole or a portion
of the supply. Such apparatus consisting of multiple switches is necessarily.
complicated and expensive, is difficult to be worked automatically, or when placed
at points distant from the generating station. We propose to overcome this diffi-
culty by the use of one or more auxiliary dynamos which may be driven by the
same source of motion as the main generating power or by an independent source,
such as an electric motor. For this purpose we wind this dynamo which we
hereafter for convenience call an "updown dynamo" or simply "updown" with two
windings on its field magnets. This winding may be arranged in the manner
described in the Patent taken out by one of us and James Swinburne No. 5168
dated April 14th 1886. The first of these windings may be a shunt winding as
therein described or the same winding may be separately excited by any convenient
source of electricity provided that it is kept as constant as possible. The second
winding may be a backward main as described in the same Patent but of very much
greater magnetising power so that a current equal to about the full output of the "
generating machinery now being dealt with, can when passing through this
backward main completely neutralise the exciting power of the first winding.
This backward main is also capable of carrying double this amount of current, and
when this is the case it is able to excite the magnets in the opposite sense to that
caused by the first winding so that the E.M.F. generated in the armature of this
"updown" will in such case be equal, and opposite to that due to the first winding
under the same conditions of speed. The second winding or backward main
however is not coupled in series with the charging lead to the accumulator as
described in the above mentioned Patent, but in our present invention is coupled in
the supply lead to the mains in such a manner that the whole current passing to

page_text: the mains away from the accumulators as well as that from the main generating
machinery must pass through it.
The working of this arrangement is as follows:-
If it be desired to work at a constant difference of potential between the supply
mains at say 240 volts the main generating power is arranged to give that E.M.F.,
and the number of accumulator cells coupled between the mains is specially chosen
to suit, so that their E.M.F. of 240 volts added to that given by the "updown" is
capable of charging these accumulators and so that their back E.M.F. assisted by
the "updown" when the second winding is operating shall be sufficient to furnish a
discharge at the same pressure.
It is obvious that our " updown" dynamo can
have its winding so arranged and the number of accumulators can be so chosen that
they can :
"
A. Be always charged by the normal difference of potential on the mains
without the use of the "updown whose E.M.F. during time of charge would
then be zero and whose function would then be solely to raise the E.M.F. of
discharging, or
B. Be always discharging at the normal difference of potential on the mains
without the aid of the "updown" whose E.M.F. would then be zero but would
have its E.M.F. added to that of the main generating power for charging only.
If the main generating power is one or more dynamos driven by one or more steam
engines or other prime movers it or they can be arranged with governors to control
the speed to as nearly as possible a constant value or by electric governors so as to
control the E.M.F. to a constant value. The automatic action of the "updown
will then compel the accumulators to discharge more or less when the demand on
the system exceeds the normal load of the generating power and vice versa will
permit the accumulators to be charged when the demand is less than the normal
power of the generating machinery.
"
The speed of the "updown" should also be kept as constant as possible and it
can be so arranged that when the E.M.F. at the terminals of the accumulators
exceeds what is necessary to charge them in other words thus indicating that they
are full; equilibrium can then be established so that little or no current passes
into them and thus the load on the main generating plant can be automatically
reduced.
Another portion of our invention relates to the use of an "updown" driven by a
motor or other suitable means and used in the manner already described but
situated at a distant point such as a distant accumulator station. Such an arrange-
ment would be of great use for equalising the E.M.F. on an electric railway
or tramway wherever accumulator stations can be arranged to be placed at
convenient intervals along the line. In such a case by the use of a suitably
arranged switch which may be operated automatically by the passage of the cars
along the line it can be arranged that any current drawn from any point on the
mains situated on the site of the accumulator station most distant from the generating
station must pass through the second winding of the "updown" and will thus
automatically cause the accumulators to assist in maintaining the E.M.F. no matter
whether this current is required for propelling the train or for doing lighting work
or any other form of work, or whether it is merely required for filling up accumu-
lators situated at a second or more distant accumulator station. By the use
of this arrangement it will be seen that accumulator stations can be made to assist
and pass their charge along the line from one station to another so that the farthest
station may receive its full charge first in order and the other stations may be filled
in rotation the one nearest to the generating station being fully charged last. In
some such cases however it may be found necessary that each accumulator station
may assist in giving current back along the line that is to say along the section
between the accumulator station and the generating station. This can be arranged
by properly operating the automatic switch above referred to so that the current
from the accumulators will pass through the second winding of the "updown" and
assist the discharge. In some cases it may be found convenient to use a system of

page_text: feeders in connection with such accumulator stations and it will be readily seen that
our arrangement of "updown_dynamo" may be conveniently worked in connection
with these feeders. It will also be seen that our invention is useful in maintaining
the E.M.F. of a distant battery station used for lighting purposes.
Another way of attaining the objects of this invention is by driving the
"updown" before described by a separate motor the speed of which would be
varied by an arrangement of winding such that it would automatically reduce such
variations of speed of this motor as in the cases before described it produces
variations in E.M.F. of the "updown" itself so that the "updown thus driven
would give the desired results by having its speed automatically varied the strength
of its own field remaining unchanged.
Dated the 14th day of April 1892.
"
WM. BROOKES & SON,
55 & 56, Chancery Lane, London, Agents for the Applicants.
COMPLETE SPECIFICATION.
Improvements in Electrical Distributing Apparatus.
We, ROOKES EVELYN BELL CROMPTON of the Arc Works Chelmsford in the
County of Essex, and WILLIAM ASHCOMBE CHAMEN of Crowley, Baker Road,
Harlesden, in the County of Middlesex, Electrical Engineers, do hereby declare
the nature of this invention and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
The objects of our invention are to overcome the difficulties found in the appli-
cation of electrical accumulators or secondary batteries for the purposes of
supplementing a supply of electrical energy whether they be used as reservoirs,
or partially as regulators, or as a safeguard against temporary breaksdown. It has
always been the desire of those using accumulators in this connection to connect
them to the system in such a manner that the generating machinery can be kept
working at a more constant load by charging the accumulators at times when the
demand is small and allowing them to discharge so as to reinforce the supply from
the generating machines at times when the demand is great. One of the chief
difficulties in such application is the very great difference between the
charging" E.M.F. or pressure required to charge a fixed number of such
accumulators up to such a degree of complete charge as is found in practice is
necessary to maintain them in good condition, and the "discharging" E.M.F. or
pressure of the same cells when discharging at the required rate. To give actual
figures if we take the well known lead couple in sulphuric acid accumulator
originally invented by Plante we find that whereas the charging E.M.F. per cell
may frequently rise to 2.5 volts the available E.M.F. or pressure of the same cell
when discharging at its maximum rate may not exceed 1.8 volts or a total difference
of 40%
66
In the past this difficulty has been got over by varying the number of accumu-
lators coupled in series between the electric mains from which they are charged,
and to which they in turn are intended to furnish the whole or a portion of the
supply. Such apparatus consisting of multiple switches is necessarily com-
plicated and expensive, is difficult to be worked automatically, or when placed
at points distant from the generating station. We propose to overcome this
difficulty by the use of one or more auxiliary dynamos which may be driven by
the same source of motion as the main generating power or by an independent
source such as an electric motor. For this purpose we wind this dynamo which we
bereafter for convenience call "updown dynamo
an
or simply "updown
two windings on its field magnets. This winding may be arranged in substantially
the manner described in the Patent taken out by one of us and James Swinburne
No. 5168 dated April 14th 1886. The first of these windings may be a shunt
winding as therein described or the same winding may be separately excited by any
"
with

page_text: convenient source of electricity provided that it is kept as constant as possible.
The second winding may be a backward main as described in the same Patent but
of very much greater magnetising power so that a current equal to about the full
output of the generating machinery now being dealt with, can when passing
through this backward main completely neutralise the exciting power of the first
winding. This backward main is also capable of carrying double this amount of
current and when this is the case it is able to excite the magnets in the opposite
sense to that caused by the first winding so that the E.M.F. generated in the
armature of this "updown" will in such case be equal and opposite to that due to
the first winding under the same conditions of speed. The second winding or 1
backward main however is not coupled in series with the charging lead to the
accumulator as described in the above mentioned Patent, but in our present
invention is coupled in the supply lead to the mains in such a manner that the
whole current passing to the mains away from the accumulators as well as that
from the main generating machinery must pass through it.
The working of this arrangement is as follows:-
If it be desired to work at a constant difference of potential between the supply
mains at say 240 volts the main generating power is arranged to give that E.M.F.,
the number of accumulator cells coupled between the mains is specially chosen to
suit, so that their E.M.F. of 240 volts added to that given by the "updown" is
capable of charging these accumulators and so that their back E.M.F. assisted by
the "updown" when the second winding is operating shall be sufficient to furnish a
discharge at the same pressure of 240 volts. It is obvious that our "updown
dynamo can have its winding so arranged and the number of accumulators can be
so chosen that they can:
"
A. Be always charged by the normal differences of potential on the mains
without the use of the "updown" whose E.M.F. during time of charge would
then be zero and whose function would then be solely to raise the E.M.F. of
discharging, or
2
B. Be always discharging at the normal difference of potential on the mains 3
without the aid of the "updown" whose E.M.F. would then be zero but would
have its E.M.F. added to that of the main generating power only at the time
when it is used for charging.
3
If the main generating power consists of one or more dynamos driven by one or
more steam engines or other prime movers it or they can be arranged with governors
to control the speed to as nearly as possible a constant value or by electric governors
so as to control the E.M.F. to a constant value. The automatic action of the
"updown" will then allow the accumulators to discharge more or less when the
demand on the system exceeds the normal load of the generating power and
rice versa will permit the accumulators to be charged when the demand is less than +
the normal power of the generating machinery. The speed of the "updown"
should also be kept as constant as possible and it can be so arranged that when the
E.M.F. at the terminals of the accumulators exceeds what is necessary to charge
them in other words thus indicating that they are full; equilibrium can then be
established so that little or no current passes into them and thus the load on the 4
main generating plant can be automatically reduced. Another portion of our
invention relates to the use of an "updown" driven by a motor or other suitable
means and used in the manner already described but situated at a distant point such
as a distant accumulator station. Such an arrangement would be of great use for
equalising the E.M.F. of the accumulators at such distant station on an electric 5
railway or tramway wherever accumulator stations can be arranged to be placed at
convenient intervals along the line. In such a case by the use of a suitably
arranged switch which may be operated automatically by the passage of the cars
along the line it can be arranged that any current drawn from any point on the
mains situated on the side of the accumulator station 'most distant from the 5
generating station must pass through the second winding of the "updown" and
will thus automatically cause the accumulators to assist in maintaining the E.M.F.

page_text: no matter whether this current is required for propelling the train or for doing
lighting work or any other form of work, or whether it is merely required for
filling up accumulators situated at a second or more distant accumulator station..
By the use of this arrangement it will be seen that accumulator statiors can be
made to assist and pass their charge along the line from one station to another_so
that the farthest station may receive its full charge first in order and the other
stations may be filled in rotation the one nearest to the generating station being fully
charged last in order. In some such cases however it may be found necessary that
each accumulator station may assist in giving current back along the line that is to
say along the section between the accumulator station and the generating station.
This can be arranged by properly operating the switch so that the current from
the accumulators will pass through the second winding of the " updown" and
assist the discharge. In some cases it may be found convenient to use a system of
feeders in connection with such accumulator stations and it will be readily seen that
our arrangement of "updown dynamo" may be conveniently worked in connection.
with these feeders. It will also be seen that our invention is useful in maintaining
the E.M.F. of a distant battery station used for lighting purposes.
In our Provisional Specification in the concluding clause we have described a
modification by means of variations in the speed of driving or separate motor in
connection with the updown but we have not so far found this suggestion to be of
sufficient practical utility and we do not therefore include the same in the present
Specification.
DESCRIPTION OF DRAWING.
In Figure 1, A represents the main generating dynamo or dynamos, B represents.
the battery of accumulators, and U represents the updown dynamo, the armature
of which is coupled in series with the branch circuit running through the battery.
The two windings of the updown dynamo are represented by W' and W², that is
to say the thin and the thick lines respectively. W' may be described as an
ordinary shunt winding. W' as a heavy main winding so proportioned that whea
carrying the full current intended to be sent out from the generating station, it
shall not only neutralise the shunt winding W', but completely reverse the polarity
of the magnets of the updown dynamo and consequently the direction of its E.M.F.
to such an extent as to allow the battery to give out the desired proportion of the
total outgoing current.
In the alternative case A, the arrangement would be as shown in Figure 2, in
which the shunt or fine winding may not be necessary, and the desired result may
be obtained with a series winding only, which is obviously inactive when no current
is passing outward to the mains, thus allowing the accumulators to be charged by
the normal E.M.F. between the mains, but which becomes active when the current
going outward to the mains reaches a certain desired value and checks or partly
checks the current charging the accumulators, whilst further increases in the main
current tend firstly to prevent altogether any current from charging the accumulators
and ultimately, by further increasing the E.M.F. of the updown dynamo, to make
the accumulators discharge at any desired rate.
In the alternative case B, the winding and arrangement will be diagramatically
represented exactly as in Figure 1, but the proportion of the main winding W
will be different, as it requires only to totally neutralise the magnetising effect of the
fine or shunt winding and not to reverse it. Thus when no current is flowing to
the mains, the E.M.F. of the updown dynamo is exerted in opposition to that of
O the battery and compels a current to pass through it and charge it. As soon
as the main current begins to exceed a certain value the E.M.F. of the updown
dynamo is partly reduced thus automatically reducing and eventually stopping the
charging current through the battery whilst when the full main current is passing,
the effect of the main winding is such as to completely neutralise that of the fine or
5 shunt winding W' so that the E.M.F. of the updown dynamo is neutralised, and the
accumulators then discharge at full rate.

page_text: In all the above cases the updown dynamo may be driven (if at the generating
station) from the same engine or other sources of power which drives the main
generating dynamo or dynamos indicated by A, the speed of which should be
approximately constant, or if it is desired to make use of this apparatus in a
distant battery station, the updown dynamo may be driven by a motor arranged to
run as nearly as possible at a constant speed and supplied with current from the
mains, or otherwise.
Figure 3 shows how the updown dynamo would be applied to one or more
accumulator sub-stations arranged at distances along a line of mains, the lettering
remaining as before, and the switch which can be worked automatically or by a
signalman in a signal box is lettered S.
When the switch is in the position shown by the full line, the connections will be
seen to be such that any current passing forward whether for driving motors or
doing other work or for charging the accumulators in more distant stations, will
pass through the main winding W2 and will tend (if it is sufficient in quantity) to
make the accumulators discharge to assist in supplying the current. If however, it
be assumed that a train is passing an accumulator station, it will be seen that on
promptly putting the switch over as shown by the dotted lines, the current which
has been and would still be going out of the battery will still pass through the main
coil and tend to make the accumulators discharge into the line, thus avoiding the
loss which might occur if the whole current had to be drawn through the trolley
wire or feeder from the preceding station.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is
1. In electrical distributing apparatus the methods or arrangements of windings
of one or more auxiliary dynamo electric machines driven by the same source of
motion as the main generating power, or otherwise driven, substantially as and for
the purpose hereinhefore set forth.
2. The method or arrangement of windings of auxiliary dynamo electric machines
for use in the distribution of electrical energy substantially as set forth with
reference to Fig. 1.
3. The method or arrangement of windings of auxiliary dynamo electric machines
for use in the distribution of electrical energy, substantially as set forth with
reference to Fig. 2.
4. The method or arrangement of auxiliary dynamos as a means of charging and
discharging distant batteries of accumulators substantially as and for the purposes
set forth and described with reference to Fig. 3.
Dated the 13th day of January 1893.
WM. BROOKES & SON,
55 & 56, Chancery Lane, London, Agents for the Applicants.