IMPROVEMENTS IN REGULATING ELECTRIC CURRENTS, AND IN THE APPARATUS OR MEANS EMPLOYED THEREIN.
Year: 1881

page_text: LETTERS PATENT to Sir William Thomson, Knight, of Glasgow College,
Doctor of Laws, and Professor of Natural Philosophy in the University and
College of Glasgow, in the County of Lanark, N.B., for an Invention of
"IMPROVEMENTS IN REGULATING ELECTRIC CURRENTS, AND IN THE APPARATUS
OR MEANS EMPLOYED THEREIN.'
د,
PROVISIONAL SPECIFICATION left by the said Sir William Thomson at
the Office of the Commissioners of Patents on the 9th July 1881.
Sir WILLIAM THOMSON, Knight, of Glasgow College, Doctor of Laws, and Professor
of Natural Philosophy in the University and College of Glasgow, in the County of
Lanark, N.B. "IMPROVEMENTS IN REGULATING ELECTRIC CURRENTS, AND IN
THE APPARATUS OR MEANS EMPLOYED THEREIN."
The first part of my Invention consists of an automatic appliance for regulating
by means of electro-magnetic force the work of an electric accumulator by
increasing or diminishing the number of working cells. One species of this
appliance gives a constant strength of current, another a constant electro-motive
force. In the former the electro magnetic force due to the whole current flowing
through a short thick coil is used; in the latter the electro magnetic force of the
branch current through a coil of long fine wire connecting the working electrodes
is used. One mechanical method by which I direct the electro magnetic force to
produce the desired result is a metallic roller, caused by it to roll over contact
pieces connected with the cells alternately by short thick metals and by wires or
resistance coils having sufficient resistance to prevent inconveniently great currents
by momentary short circuitings of cells. The roller itself is connected by a sliding
contact with the circuit in which the work is done.
The second part of my Invention is an improved method for keeping the
strength of an electric current or the electro motive force between two conductors
as nearly constant as may be, while changes are made in the work done by the
current or by currents between the two conductors in cases in which a simple
Pasics 1031

page_text: electro magnetic appliance has not the requisite power to effect the regulation.
It consists in applying when the current or electro-motive force becomes too
strong a small dynamo-electric or magneto-electric engine to do the work needed
to diminish the steam power driving the main dynamo-electric machine by which
the current is produced, or otherwise to diminish the speed of the machine or its
electric efficiency, or to diminish the battery or the accumulator when the current
is sustained by battery or accumulator. An electric-magnetic make-and-break of
ordinary type or of the kind used in the third part of my Invention, and described
below, is used in the present case to make and break the contacts for throwing on
or off the small dynamo or magneto engine. When it is the strength of a current
that is to be regulated the electrodes of the regulating engine are applied to points
of the main circuit or the two sides of a contact which is broken when the current
is too strong and made again when the current is not too strong. When it
is e. m. f. that is to be regulated on electrodes of the regulating engine is kept in
connection with one of the main conductors. The other is put into connection
with the other main conductor when the e. m. f. is too strong, and this connection
is broken when the e. m. f. is not too strong. In each case the instantaneous effect
of throwing the coils of the regulating engine into circuit is to check suddenly the
too strong electric action. In the former case this is done by augmentation of
resistance in the main circuit; in the latter it is done by shunting part of the
current of the source from the external circuit by letting it pass through the coils
of the regulating engine. In each case the engine gradually reduces the electric
force of the source until the regulating engine is thrown out of circuit and allowed
to remain out of circuit by the automatic make-and-break.
When the current or the e. m. f. becomes too weak at any time I use a
corresponding automatic arrangement to direct small regulating dynamo or magneto
engine to auginent the exciting power by a reverse action to that described above.
The same engine may serve for both the auginenting and the diminishing of the
exciting power by arranging that it shall be connected so as to run in one
direction when the current or c. m. f. is too great, and in the opposite direction
when too small.
The third part of my Invention is an automatic make and break by which when
arrangements are made to charge an accumulator the charging circuit is made or
broken according as the electro motive force suffices or does not suffice to add to
the charge in the accumulator, and is also broken when the current is stronger
than desired. One form of this make-break consists of a stiff bar like the beam of
a balance carrying on one end a circular coil I of a great length of fine insulated
copper wire, and on the other end a single circle or a circular coil of a short length
of thick copper wire Q, the planes of these coils I and Q passing through the pivot
axis of the beam. The ends of the coil I are connected with two cups of mercury
S, F, by fine wires properly placed to afford the requisite freedom of motion to the
beam. The ends of the coil Q are connected by thick copper wire with pieces of
thick platinum wire dipping into S and F, which are so placed that when the
beam tilts up one of the platinums is drawn out of the mercury. The cup S is
connected to one pole of the source by thick wire, and F to the corresponding pole
of the accumulator. The other poles of source and accumulator are permanently
connected by thick wire. Fixed steel magnets are so placed in the neighbourhood
of I and Q as to cause the beam to tilt Q down when there is a current through I
in the proper direction, and to keep it down in virtue of the current through Q
when the mercury contact is made. The beam is so balanced that should the
charging current at any time cease Q shall be tilted up and one of the mercury
contacts broken. Should the current become reversed very suddenly the magnets
acting on accelerate this action. The length and fineness of the wire of I must be
such that the current backing through it when the e. m. f. of the source falls short
of that of the accumulator, is not enough to make any serious loss from the
accumulator or to damage the source. To guard against possible damage to the
source through accidental failure of the automatic make-break, or because of its not

page_text: acting quickly enough in the event of a sudden stoppage or diminution of the
c. m. f. of the source or through accidental short circuiting of the accumulator, I
introduce in one of the electrodes between source and accumulator a short length
of wire, fine enough to melt before damage can be done by any current in either
direction through it. Or I use a second electro-magnetic make and break adjusted
to break circuit when the current exceeds a certain limit, and to make again when
the e. m. f. has fallen sufficiently to give not too strong a current.
The fourth part of my Invention consists of arrangements for applying the
accumulator or parts of it to the source when recharging is required and freeing
the accumulator or parts of it when ready for work, and apply them to the work
when wanted.
When the source is a dynamo machine of ordinary type, that is, having the
electro magnet and the moving coils in direct circuit with the external work-
circuit (so that the strength of the current through the magnet coils is diminished
by increase of resistance in the external circuit) the reversal of the current through
the magnet coils in the event of the accumulator overpowering the dynamo is
prevented by the automatic make-break. But I prefer in many cases to separate
the accumulator into two parts and to put one of them in circuit with the moving
coils and the other separately in circuit with the magnet coils, and to make no
common circuit through the moving coils and the magnet coils. Thus the work
that must be done in the magnet coils is done by a part of the accumulator,
while the rest of the accumulator is being charged. The part of the accumulator
thus doing work must automatically or by an attendant be transferred to the
charging circuit as often as is necessary to sufficiently recharge it, and another
part of the accumulator applied to do the work instead of it. No breaking of the
accumulator into parts for this purpose is needed when the dynamo is of the
shunt type described by Mr. Siemens in a communication to the Royal Society, of
which an abstract is published in the proceedings of the Royal Society for 1880.
In this case the accumulator sustains the electro magnet and never can send the
current in the wrong direction through its coils in the event of the dynamo
stopping, or of its c. m. f. falling short of that of the accumulator through any
accident or because of the machine running for a time at too small a speed; but
the automatic make-break is still useful to prevent waste from the accumulator or
too strong a current through any of the coils of the dynamo.
When the accumulator is used to give electric light or for other purposes in
which a more constant current than that attainable by a dynamo machine is
wanted, I divide the accumulator into parts and keep one part of it producing the
electric light or doing the other work required, while the remainder of it is being
recharged by the dynamo, and I regularly remove single cells or groups of cells
from the working part of the accumulator, and replace them by parts taken from
the portion which is being charged, and as nearly as may be simultaneously I put
the parts taken from the working portion into the charging circuit, so that they may
be recharged. This I do either automatically or by hand. To do it automatically
I arrange the two circuits A, B, C x x x x x Y, and A', B¹, C' x x x x x Y in the
form of two neighbouring circles. The first circuit may be broken at any one of
the points A, B, C × × × xx Y, supposed to be twenty-five in number for the
sake of example, and the second circuit may be broken at any of the corresponding
points A, B, C' x × × × × Y The first circuit is broken at Y, and the two
charging electrodes are applied to the contact pieces thus separated. The second
circuit is broken at the point Y', and the electrodes leading to the external work
are applied to its separated contact pieces. The accumulator, consisting of 24 cells
marked a, b, c x x x
xx, is arranged in the fashion of Volta's crown of cups in the
neighbourhood of these circles. Suppose the power of the dynamo and the work
to be done by the aid of the accumulator are such that S cells may conveniently
be kept in the charging circuit, and 16 cells in the working circuit. Eight of
the junctions of the first circle, say, A, B, C × × × H, are broken, and electrodes
of the 8 cells a, b, c xxx h, are interposed, and the 16 junctions I', J¹, K¹ xxx X¹,
x

page_text: of the second circle are opened and electrodes from the corresponding cells
interposed. From time to time cell after cell is removed from one circuit and
placed in the other, as explained above. Suppose, for example, at any time the
cells which are being charged are connected at the junctions W, X, A, B, C, D, E, F,
and the working cells at G, H, I, J¹, U', V¹. When this state of things has
lasted for the proper time, the cell g is removed from G¹ to G, and the cell wis
removed from W to W. Next after the proper time has passed the cell is
removed from H¹ to H, and x from X to X. Next the cell i is removed from
I to I, and a is removed from A to A¹, and so on. This may be done by hand by
an attendant, but I prefer to do it automatically by aid of a shaft kept rotating
with a slow motion in the proper period by a wheel-work from the dynamo or
from the engine driving the dynamo. This shaft carries a weight with proper
projections to act upon the contact pieces directly or through levers. This weight
turns with the shaft, and is gradually lifted up and fall suddenly, so as to make
the proper changes of connections with sufficient speed to not sensibly disturb the
light or other work that is being done, nor the electrical or mechanical conditions
of the dynamo and driving engine in the other mechanism, making automatically
the requisite changes of connection with sufficient quickness may be used.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Sir William Thomson in the Great Seal Patent Office on the
9th January 1882.
Sir WILLIAM THOMSON, Knight, of Glasgow College, Doctor of Laws, and Professor
of Natural Philosophy in the University and College of Glasgow, in the County of
Lanark, N.B. IMPROVEMENTS IN REGULATING ELECTRIC CURRENTS, AND IN
THE APPARATUS OR MEANS EMPLOYED THEREIN."
The first part of my Invention consists of an automatic appliance for regulating
by means of electro-magnetic force the work of an electric accumulator or of a
primary voltaic battery by increasing or diminishing the number of working cells.
One species of this appliance gives a constant strength of current, another a
constant electro-motive force. In the former case the electro-magnetic force due
to the whole current flowing through a short thick coil is used, in the latter case
the electro-magnetic force of the branch current through a coil of long fine wire
connecting the working electrodes is used. One mechanical method by which I
direct the electro-magnetic force to produce the desired result is a metallic roller
rolling over contact pieces connected with the cells alternately by short thick
metals, and by wires or resistance coils having sufficient resistance to prevent
inconveniently great currents by momentary short circuitings of cells. Each such
resistance wire or coil is doubled on itself with the two parts mutually insulated,
whether by an insulating coat or by air, for the purpose of minimising the quasi
inertia produced by self induction. The roller itself is connected by a sliding
contact, or by another rolling contact with the circuit in which the work is done.
I also use the same appliance for regulating the charging of a secondary battery, so
that those cells which have been most drawn upon in the use of the battery shall
have the greatest amount of charging current given to them, and that the whole
battery may be reinstated to its proper full intensity before the charging process is
stopped.
The accompanying Drawing, Figure 1, with the following explanation, illustrates
the action of the appliance, the mechanical details of which may be carried out in
many different ways with almost equal advantage.
A represents the first plate of the first cell, and I, the second plate of the last cell
in the series constituting the battery; B, the connected second plate of the first
cell, and first plate of the second cell; C, D, E, F, G, H, represent similarly the
other connected plates of the battery; a¹, b², 61, c³, c¹, and successive letters
to h², h, i, ', represent insulated studs. The studs a¹ to h are connected to the
plates A, B, C, to H, by short thick wires. The studs 62 to 2 are connected to the
same plates by wires having considerable resistance, each doubled on itself to
minimise the electro-magnetic inertia. The plate A is connected by a wire W
with the work circuit when the battery is doing work, or with the charging circuit
when it is being charged, if it is a secondary battery; R represents a roller by
which one, and at times two, of the studs a¹ to i¹ are put in connection with the
working or charging circuit through a wire W. For simplicity this wire is
indicated as connected with the axis of the roller. It may be very conveniently so
connected by a slipping contact, and any convenient guide-frame may be employed
to guide the axis of the roller with just the freedom required for its proper motion.
I prefer however generally to produce the connection between the studs a, b, b, etc.,
and the wire W, by letting the roller roll in a V groove, of which one of the sides
is composed, of flat inclined faces of the studs a', 62, b¹, etc., and the other side is a
straight continuous metal bar to which the wire W₁ is connected. This plan for
rolling contacts, with a suitable guide-frame for the axis of the roller, is employed

page_text: and hereinafter explained in connection with Figures 2, 3, 5, or a spherical roller
without axle, or truck, or guide frame below may be used, which may be moved by
hand or mechanically by a fork.
The second part of my Invention is an improved method for keeping the strength
of an electric current or the electro-motive force between two conductors, as nearly
constant as may be, while changes are made in the work done by the current or by
currents between the two conductors, in cases in which a simpler electro-magnetic
appliance has not the requisite power to effect the regulation. It consists in
applying, when the current or electro-motive force becomes too strong, a small
dynamo-electric or magneto-electric engine to do the work needed to diminish the
steam power for driving the main dynamo-electric machine by which the current is
produced, or otherwise to diminish the speed of the machine or its electric efficiency,
or to diminish the battery or the accumulator, when the current is sustained by
battery or accumulator. An electro-magnetic make-and-break of ordinary type or
of the kind used in the third part of my present Invention and hereinafter described,
is used in the present case to make and break the contacts for throwing on or off
the small dynamo or magneto engine. When it is the strength of a current that is
to be regulated, the electrodes of the regulating engine are applied to points of the
main circuit on the two sides of a contact, which is broken when the current is too
strong, and made again when the current is not too strong. When it is electro-
motive force that is to be regulated, one electrode of the regulating engine is kept
in connection with one of the main conductors. The other is put into connection
with the other main conductor when the electro-motive force is too strong, and
this connection is broken when the electro-motive force is not too strong. In each
case the instantaneous effect of throwing the coils of the regulating engine into
circuit is to check suddenly the too strong electric action. In the former case this
is done by augmentation of resistance in the main circuit, in the latter it is done
by shunting part of the current of the source from the external circuit by letting it
pass through the coils of the regulating engine. In each case the regulating engine
gradually reduces the electric force of the source until the regulating engine is
thrown out of circuit and allowed to remain out of circuit by the automatic make-
and-break. When the current or the electro-motive force becomes too weak at
any time, I use a corresponding automatic arrangement to direct an electro
magnetic motor to augment the exciting power by a reverse action to that described
above. The same electro magnetic motor may serve for both the augmenting and
the diminishing of the exciting power by arranging that it shall be connected so as
to run in one direction when the current or electro motive force is too great, and in
the opposite direction when too small.
The regulating engine above referred to may be an electro magnetic motor of
any type. I prefer one in which a permanent magnet is used and which gives
motion in one direction or the other according as the working current is in one
direction or the other. When not too great regulating motion is required I use a
regulating engine without a commutator, doing its work by a single stroke by
means of the electro-magnetic action of a powerful steel magnet on a moveable
coil, as in the make and break instrument hereinafter described in the third part
of my Invention. One example of a particular apparatus for carrying out the
second part of my Invention is represented in Figures 2 to 4 of the accompanying
Drawings. E is the moveable coil; W, a counterpoise for it; and M, the actuating
steel magnet in the regulating motor; e, w, and m represent the similar parts made
smaller in the primary regulator or double acting relay, as I may call it for
brevity; F is a pan for placing adjustment weights in, in applications wherein such
are necessary, as when the regulating motor is used direct without relay;
K, K, and k, k, are knife edges supporting the two balance-beams; R (Figures 2, 3,
and 5) is the contact roller; S, S, are the studs forming one side of a V groove, in
which the roller R rolls; V, in Figures 2 and 5, is the continuous metal forming
the other face of the V groove.
B¹, H¹, H, B, is a guiding carriage, which has the roller R pivotted on it at J

page_text: (Figures 3 and 5); B, B¹, are balls fixed to the ends of this carriage, which are
guided by six planes, of which only three can be simultaneously touched by the
balls. Two of these planes at G₁ are vertical planes at a distance apart slightly
exceeding the diameter of the ball B¹. The other four are the four sides of a
horizontal square tube G, along which the ball B moves. The diameter of this
tube is slightly greater than the diameter of the ball B.
P is a pin fixed to a long arm A coming down from the beam of the balance,
being carried by a socket attached thereto. This pin, by pressing on one or other
of two bars b, b, fixed to the carriage, causes the carriage to move in one direction
or other and stops it again by the motion of the regulating engine beam according
to the electro magnetic force experienced by the coil E from the lower pole of the
magnet M.
Qq, Figures 2 and 4, represent the contacts made by the double acting relay, so
as to send currents in opposite directions through E according as e tilts w up or
down. There is sufficient spring in the arms carrying the platinized contact
pieces q to ensure that a very moderate tilting force brings each into contact with
the proper fixed stud.
In Figure 5 a resistance coil is represented in section by C, C, C. The studs S, S, S,
are connected by stout conductors L, L, L, with points in the line of the wire of
this coil. Every stud is connected so to the coil. The lines of connection of three
successive studs are on three different levels to allow the requisite solderings to be
made, simply because there would not be room for the soldering of the said
conductors L side by side. I find 40 studs connected to 40 points at every third
turn of a resistance coil of 120 turns of stout iron wire on a sheet iron cylinder of
six inches diameter coated with asbestos cloth to give a good regulating appliance
for equalizing the potential on the house-supply wires for incandescent lamps in a
sniall house by throwing in more or less resistance between one of those wires and
the corresponding main according as the number of lamps excited is less or more.
The third part of my Invention is an automatic make-and-break, by which,
when arrangements are made to charge an accumulator, the charging circuit is
made or broken according as the electro-motive force suffices or does not suffice to
add to the charge in the accumulator, and is also broken when the current is
stronger than desired. One form of this make-break, which is represented in
elevation in Figure 6 and in plan with the magnets in section in Figure 7, consists
of a stiff bar A, A¹, like the beam of a balance carrying on one end a circular coil I
of a great length of fine insulated copper wire and on the other end a single circle
or a circular coil, of a short length of thick copper wire Q, the planes of these coils I
and Q passing through the pivot-axis or line of knife-edges of the beams A, A¹.
The ends of the coil I are connected with two cups of mercury S, F, by fine wires
properly placed to afford the requisite freedom of motion to the beam. The ends of
the coil are connected by thick copper wire with pieces of thick platinum or
copper wire dipping into the mercury in the cups S and F which are so placed.
that when the beam tilts Q up. one or both of the platinums is drawn out of the
mercury. The cup S is connected to one pole of the source by the thick wire S',
and the cup F is connected by the thick wire F¹ to the corresponding pole of the
accumulator, the said wires dipping into the mercury in the said cups. The other
poles of source and accumulator are permanently connected with one another by
thick wire. Fixed steel magnets M, M³, are so placed in the neighbourhood of I
and Qas to cause the beam A, A', to tilt Q down when there is a current through I in¸
the proper direction, so as by this tilting to make a circuit through the mercury cups
and the said coil Q, and to keep it down in virtue of the current through Qwhen
the mercury contact is made. The beam A, A', is so balanced that should the
charging current at any time cease, Q shall be tilted up, and one or both of the
mercury contacts broken. Should the current become reversed very suddenly
through sudden stoppage or slowing of the charging dynamo or other accident, the
magnets acting on Q accelerate the tilting motion. The length and fineness of the
wire of I must be such that the current backing through it, when the electro-

page_text: motive force of the source falls short of that of the accumulator, is not enough to
make any serious loss from the accumulator or to damage the source. To guard
against possible damage to the source through accidental failure of the automatic
make-and-break, or because of its not acting quickly enough in the event of a
sudden stoppage or diminution of the electro-motive force of the source, or through
accidental short-circuiting of the accumulator, I sometimes introduce in one of the
electrodes between source and accumulator, a short length of wire, fiue enough to
melt before damage can be done by any current in either direction through it. Or
I use a second electro-magnetic make-and-break with a single moveable coil acting
just as does the coil Q, but weighted so as to be tilted up and to break circuit
when the current exceeds a certain limit, and to make again when the electro-
motive force has fallen sufficiently to give not too strong a current.
This adjustment is performed as in the regulator shewn in Figures 2 to 4 by a
less or greater weight at the end of the beam, remote from the moveable coil, or by
a greater or less weight on the end next the coil. It may be varied at pleasure,
according as a greater or a less current is to be allowed to flow. Platinized or
other solid metal contacts may be used instead of the mercury cups S and F. Two
pairs of terminals T, T¹, are shewn in the Drawing, with provision for breaking the
connection between them, so that the instrument may be used in cases in which
one of the two coils only is required, or in which it is convenient to vary their
connections.
The fourth part of my Invention consists of arrangements for applying the
accumulator or parts of it to the source when recharging is required, and freeing
the accumulator or parts of it when ready for work, and applying them to the
work when wanted.
When the source is a dynamo machine of ordinary type, that is, having the
electro-magnet and the moving coils in direct circuit with the external work
circuit (so that the strength of the current through the magnet-coils is diminished
by increase of resistance in the external circuit), the reversal of the current through
the magnet-coils in the event of the accumulator overpowering the dynamo is
prevented by the automatic make-and-break. But I prefer in many cases to
separate the accumulator into two parts and to put one of them in circuit with
the moving coils, and the other separately in circuit with the magnet-coils and to
make no common circuit through the moving coils and the magnet-coils. Thus
the work that must be done in the magnet-coils is done by a part of the accumu-
lator while the rest of the accumulator is being charged. The part of the
accumulator thus doing work must automatically or by an attendant be transferred
to the charging circuit as often as is necessary to sufficiently recharge it, and
another part of the accumulator must be applied to do the work instead of it. No
breaking of the accumulator into parts for this purpose is needed when the dynamo
is of the shunt type described by Mr. Siemens in a communication to the Royal
Society, of which an abstract is published in the proceedings of the Royal Society
for 1880. In this case the accumulator sustains the electro-magnet, and never can
send the current in the wrong direction through its coils, in the event of the
dynamo stopping or of its electro-motive force falling short of that of the accumu-
lator through any accident or because of the machine running for a time at too
small a speed; but the automatic make-break is still useful to prevent waste
from the accumulator or too strong a current through any of the coils of the
dynamo.
When the accumulator is used to give electric light or for other purposes in
which a more constant current than that obtainable directly from a dynamo is
wanted, or when it is desired to work with an electro-motive force different from
that obtainable directly from the dynamo, I divide the accumulator into parts and
keep one part of it producing the electric light or doing the other work required
while the remainder of it is being recharged by the dynamo, and I regularly
remove single cells or groups of cells from the working part of the accumulator
and replace them by parts taken from the portion which is being charged; and as

page_text: * *
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* *
nearly as may be simultaneously I put the parts taken from the working portion
into the charging circuit so that they may be recharged.
This I do either auto-
matically or by hand. To do it automatically I arrange, as illustrated in Figure 8,
two circuits A, B, C,✶✶✶✶✶ Z, and A', B', C', **
Z³, in the form of two
neighbouring circles. The first circuit may be broken at any one of the points A,
B, C,
Z, supposed to be thirty two in number for the sake of example,
and the second circuit may be broken at any of the corresponding points A¹, B',
C', ***
Z. The first circuit is permanently broken at a point K between two
of the make-and-break junctions A, B, C, etc., and the two charging electrodes are
applied to the contact pieces thus separated. The second circuit is broken per-
manently at a point K', and the electrodes leading to the external work are applied
to its separated contact pieces. The accumulator, consisting of 32 cells marked a,
b, c, x x x x 2, is arranged after the manner of Volta's crown of cups in the neigh-
bourhood of these circles. Suppose the power of the dynamo and the work to be
done by aid of the accumulator are such that twenty eight cells may conveniently
be kept in the charge circuit and four cells in the working circuit, twenty-eight of
the junctions of the first circle, say, A, B, C, D - U, Y, are broken and
electrodes of twenty eight a, b, c, d - w, x, are interposed; and four junctions
W¹, X', Y¹, Z', of the second circle are opened and electrodes from the corresponding
cells interposed. From time to time cell after cell is removed from one circuit and
placed in the other, as explained above. Suppose, for example, at any time the
cells which are being charged are, as shewn in Figure 8, connected at the junctions
A, B, CT, U, V, and the working cells at W, X, Y, Z. When this state
of things has lasted for the proper time, the cell wis removed from W' to W, and
the cell a is removed from A to A¹. Next, after the proper time has passed, the
cell x is removed from X' to X, and b from B to B¹. Next the cell 3 is removed
from Y¹ to Y, and c is removed from C to C¹, and so on. This may be done by
hand by an attendant, but I prefer to do it automatically by aid of a shaft kept
rotating with a slow motion in the proper period by wheelwork from the dynamo
or from the engine driving the dynamo. This shaft carries a weight with proper
projections to act upon the contact pieces directly or through levers. This weight
turns with the shaft and is gradually lifted up and let fall suddenly so as to make
the proper changes of connections with sufficient speed to not sensibly disturb the
light or other work that is being done on the electrical or mechanical conditions of
the dynamo and driving engine. Any other mechanism making automatically the
requisite changes of connection with sufficient quickness may be used.
The arrangement described above, with reference to Figure 8, is adapted to cases
in which the quantities of electricity passed may be conveniently made nearly the
same in the charging and working circuits. When the quantities of electricity
passed in the charging and working circuits are to be very different, I alter the
arrangement of the battery from series to parallels, or vice versa, in passing from
the charging to the working circuits. One way of performing this process is
represented in Figure 9, in which a portion of a large number of cells, still arranged
after the manner of Volta's crown of cups, and the corresponding connections and
changes of connections are shewn. W, W¹, represent long metal bars or rods
connected with the electrodes of the working circuit; x represents a single cell or a
group of cells in series; similarly y, z, a, b, c . . . . . k, l, m, n, o, p, represent
single cells or groups of equal numbers of cells in series x, y², z¹, b₁ ='" k¹, l¹,
m², n', o¹, represent insulated metallic studs; x, x³, represent insulated studs
connected with a¹ respectively by a short thick wire and by a wire having con-
siderable resistance, for the purpose herein before first described and explained by
aid of Figure 1; y², y³, 3, 3, etc., represent studs similarly connected with y, z¹, etc.;
C, C¹, represent contact rollers connected by electrodes D, D', with the charging
dynamo. These rollers are pivotted on a truck of wood or other insulating
material, by means of which they are carried uniformly round the circle of the
contact pieces ³, x³, y², y³, z², 5³, a², a³, b², b³,
³, k³, 12, 13, m³, m³, n², n³,
o, o³, etc. This truck carries a plough by which contact tumblers or springs are

page_text: shifted over from the studs m³, n¹, o¹, etc., in regular order to the bars W, W', just
before the contact roller C¹ reaches the corresponding studs m², m³, n³, n³, o², o³, etc.
The truck carries another plough by which the contact tumblers or springs are
shifted back from the bars W, WI, to the studs a¹, b', etc., just before the contact
roller C reaches the corresponding studs 62, 63, c², c³, etc. It will be understood
that Figure 9 being a diagram, for the sake of clearness of delineation, the contact
tumblers are represented as having a wide range of motion to change their
contacts. In practice it is evident that their range of motion may be only of such
extent as will make and break their contact in the manner explained, the bars
W, W₁, and plates or studs a' to z¹ being arranged in such proximity as will allow
a movement of the contact tumblers through a small extent to break contact with
the bars and come into contact with the plates or studs, or vice versa. It will be
understood without further description or illustration that two ploughs or inclined
surfaces may be arranged upon the roller carriage; to effect this, the one lifting
the tumblers for the one contact and the other depressing them for the other
contact. The contact tumblers have the effect of connecting the two poles of each
cell or group with the studs a', b', etc., and the rails W, WI, alternately in regular
order, as shewn in the diagram. Suppose, for example, the whole number of cells
or groups to be two hundred, and the number from 6 to m inclusive to be one
hundred, the arrangement will then give one hundred cells or groups applied in
parallels to the electrodes of the work-circuit, and one hundred in series receiving
charge from the dynamo. If x, y, z, etc., bo groups of forty cells each, of Plante's,
or Faure's, or other secondary battery, the arrangement would suit the case of
using for electric lighting in a town the energy developed by a distant dynamo
(or series of dynamos) adapted to give a moderately strong current with a great
potential of 9000 Volts or thereabout. In order that a secondary battery of small
capacity, provided it is of small enough resistance, may be utilized for the purpose,
I employ a very rapid motion of the truck and rollers. Thus, for example, I may
cause it to go regularly round the whole circle in two minutes, so that each group
will be called upon only for one minute to do work and will be recharged in the
next minute. Even if a secondary battery of large capacity be used, it is possible
that some such rapid motion as this would allow its transmutation of energy to
be performed with less of waste than would a slower motion.
Having now described and particularly ascertained the nature of my said
Invention, and the system, mode, or manner in or under which the same is or
may be used or practically carried into effect, I would observe in conclusion that
what I consider to be novel and original, and therefore claim as the Invention
secured to me by the herein before in part recited Letters Patent is,-
First. The plan of connecting insulated studs alternately by short thick metals,
and by wires or resistance coils described in the first part above, and explained in
connection with Figure 1 and Figure 9 of the accompanying Drawings, for the
purpose of allowing cell after cell to be thrown into connection or out of connection
without breaking circuit, and without inconveniently great currents from momentary
short circuitings of cells or groups of cells.
Second. The plan of contact roller rolling in a V groove with one side continuous
metal, and the other composed of detached studs of metal placed lengthwise along
the track of the roller for the purpose of varying the connections in an electric
circuit, as described more particularly with reference to the roller R and groove
formed by the plate V and studs S, illustrated in Figures 2, 3, and 5 of the
accompanying Drawings.
Third. The combination of a contact roller for varying electric contacts in a
circuit with an electro-magnetic appliance by which the roller is moved to and
fro continuously according as an electric current through the apparatus has greater
or less values for the purpose of regulating a difference of potential or an electric
current.
Fourth. The combination of the electro-magnetic system described in the last
preceding claiming clause with a more delicate electro-magnetic appliance on the

page_text: plan of, as it were, a double-acting relay, by which the roller is kept moving in one
direction during any time when the current or potential to be regulated exceeds
a certain limit, and in the other direction when the current or potential falls
short of a certain limit.
Fifth. The combination of a fixed steel magnet with a coil moveable in its
neighbourhood with contact pieces moved by the coil, in such a manner as to make
and break contacts for the purpose of regulating electric, potential, or strength of
electric currents.
Sixth. The mode of charging and working a secondary battery by separating it
into parts by additions of cells to one end of a series, and taking off of cells from
the other end of the same series and joining the detached parts, whether in series
or in parallels, so that while some of the parts are doing work others may be
receiving fresh charge, substantially as described above with reference to Figure 8
and Figure 9 of the accompanying Drawings.
In witness whereof, I, the said Sir William Thomson, have to this my Specifi-
cation set my hand and seal, this Twenty second day of December, in
the year of our Lord One thousand eight hundred and eighty one.

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