Improvements in Resistance and Contact Apparatus for Electric Currents.
Year: 1897

page_text: Improvements in Resistance and Contact Apparatus for Electric
Currents.
We, DUNCAN STEWART AND COMPANY, LIMITED, of London Road Iron Works,
in the County of Glasgow, North Britain, Engineers, and HENRY LYON, of
38, Whitevale Street, in the same county, Electrical Engineer, do hereby declare
the nature of this invention to be as follows, that is to say:-
Our said invention comprises new and improved arrangements of resistance
and contact apparatus for electric currents, which arrangements are advanta-
geously applicable for various purposes.
Our present invention consists in combining in various ways two or more
elements together, and, in some cases, with other parts, each such element being
of a kind described in Lyon and Leslie's Patent Specification No. 5474 of 1890,
and consisting of a jar of earthenware or other suitable material having at its
bottom a conical metal cup, connected through the bottom with an external
metal conductor, whilst movable up and down in the jar there is a metal cone
which when in its lowest position fits inside of the cup. Water or other suitable
feebly conducting liquid such as a solution of a salt of the same metal as that
of which the cup and cone are made, is put in the jar so that its upper surface.is
at. a suitable height above the cup. The cone is connected to a separate metal
conductor, and when it is entirely above the liquid the circuit is broken.
the cone being lowered its point first makes contact with the liquid (without
sparking) and the resistance of the liquid gradually diminishes as the cone
descends until it makes complete contact with the cup. If the cone is stopped
short of the cup the electric current will experience resistance corresponding to
the depth of liquid it has to pass through.
On
In one improved arrangement two elements are combined and the cone of one
jar is suspended by a non-conducting cord passing round an overhead pulley
and down to the cone of the other jer. When the cones are at the same level
neither is in contact with the liquid whilst either can be lowered into it by
turning the pulley. The cones are connected by flexible coils of wire to separate
conductors, the cups being connected to one conductor: or the cups may be con-
nected to separate conductors and the cones to a single one. This arrangement
is suitable for reversing an electric current for any purpose, as for example for
actuating a motor, the reversal being gradually effected. In cases in which it is
desirable to have the resistances in the two jars equal, they may be connected
by a pipe at the bottom with a stopcock, and in connection with such pipe there
may be fitted a glass gauge tube to show the height of the liquid in the jars.

page_text: In other arrangements two or more pairs of the elements are combined, there
being a double row of elements with an overhead shaft with pulleys on it, one
for each pair of elements. The shaft may be turned by means of a worm and
worm wheel or other gearing for moving the cones of all the elements simul-
taneously. The pulleys, however have separate handles fitted in connection with
them so that any pulley can be moved independently of the others when desired,
the handle of each being arranged to engage each pulley with the shaft and
to release it therefrom when handled to move it separately. A battery of elements
of this kind may be combined with various combinations of switch or plug
apparatus controlling a number of different conductors or leads. The arrange-
ment forms compact and easily manipulated apparatus for various purposes, as
for example for controlling colored and uncolored lights for scenic effects in a
theatre. The resistance liquid in the series of jars may be made to have the
same level in all of them or in any portion of them, by means of pipes with
stopcocks connecting their bottoms.
In a case in which the direction of a shunt current has to be reversed - when
that of a main circuit is reversed, we combine a pair of main elements with a
pair of elements which will generally be smaller, the cones of the two pairs
being moved together by means of one pulley having grooves for the several
suspending cords; or separate pulleys may be arranged for acting independently
on either current.
Dated this Sirth day of December 1897.
COMPLETE SPECIFICATION.
Improvements in Resistance and Contact Apparatus for Electric
Currents.
We, DUNCAN STEWART AND COMPANY, LIMITED, of London Road Iron Works,
in the County of Glasgow, North Britain, Engineers, and HENRY LYON, of
38, Whitevale Street, in the same county, Electrical Engineer, 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,
that is to say
The said invention comprises new and improved arrangements of resistance
and contact apparatus for electric currents, which arrangements are advanta-
geously applicable for various purposes.
The present invention consists in combining in various ways two or more
elements together, and in some cases, with other parts, each such element being
of a kind described in Lyon and Leslie's Patent Specification No. 5474 of 1890.
And in order that the said invention and the manner of performing the same
may be properly understood we hereunto append three sheets of explanatory draw-
ings to be hereinafter referred to in describing the improvements.
Figure 1, on Sheet 1, of the accompanying drawing is a transverse vertical
section showing one modification of the improvements. Figure 2, is a plan,
and Figure 3, a longitudinal vertical section of a second modification. Figure 4,
on Sheet 2, is a horizontal section and Figures 5, and 6, vertical sections as
at right angles to each other of a third modification. Figure 7, on Sheet 3, is

page_text: a side elevation and Figure 8, a sectional elevation as at right angles to Figure 7,.
showing a fourth modification. In these drawings the same reference letters and
numerals are used to mark the same or like parts wherever they are repeated.
As shown in Figure 1, the improved apparatus has in combination with other
parts two jars, A1, A2, of earthenware or other suitable material, having at
the bottom of each jar a conical metal cup, B1, B2, connected through the
bottom with an external metal conductor, C, which is connected to the con-
ductor of the main electric supply. In each jar, A1, A2, there is a metal
cone, C1, C2, which is suspended by a non-conducting cord, D, passing round
an overhead pulley, E, on a shaft, F, and down to the cone of the other jar. The
pulley, E, has a handle, E1, by which its movement is effected. The cones, C1, C2,
are connected by flexible coils of wire, D1, D2, to terminals, F1, F2, on a
board, E2, placed above the jars, A1, A2, and from which board brackets, G,
extend upwards to carry the overhead shaft, F. The terminals, F1, F2, may
have connected to them separate metal conductors, K. Water or other suitable
feebly conducting liquid such as a solution of a salt of the same metal as that
of which the cups, B1, B2, and cones, C1, C2, are made is put in each
jar, A1, A2, so that its upper surface is at a suitable height above the cups.
The liquid in the jars, A1, A2, may be made to have the same level in both
by means of a pipe, G 1, connecting their bottoms.
When the cones, C1, C2, are both entirely above the liquid as shown the
circuits are broken. On moving the pulley, E, so as to lower either cone, C1,
or C2, the point of that cone first makes contact with the liquid (without spark-
ing) and the resistance of the liquid gradually diminishes as the cone descends
until it makes complete contact with its cup, B1, or B2. If either cone is
stopped short of its cup the electric current will experience resistance corres-
ponding to the depth of liquid it has to pass through.
This arrangement is suitable for switching an electric current from a main.
conductor, C, on to one or other of the other two conductors, K, connected to
the terminals, F1, F2, for any purpose as for example for actuating a motor, the
reversal being gradually effected in the manner described.
In the modification shown in Figures 2, and 3, there is a double row of
jars, A1, A2, arranged opposite each other in pairs. The overhead pulley, E,
for each pair of jars, has a tubular centre, H, which is formed with a projec-
tion, H1, through which the handle, E1, is screwed so that its end bears on
the shaft, F, and thus fixes the pulley in any desired position on the shaft. The
shaft, F, may be turned by means of a worm and wormwheel, J, or other gearing
for moving the cones, C1, C2, of all the jars simultaneously, whilst on unscrew-.
ing the handle, E1, for any pulley, E, that pulley can be moved independently.
of the others when desired. To prevent confusion in the drawings conductors, K,
are shown as being led only from the terminals, F 1, F 2, of the four jars at the
left hand side of Figure 2, to four groups of switches or blocks, L, for contact
plugs, each group of which may be supposed to control three lights of different
colors for example. It is to be understood that the other jars, A1, A2, may be
similarly connected to other switches or plug blocks and that there may be
only two or any number of pairs of jars. The pipe, G1, connecting the bottom
of the jars, may be fitted with a stopcock, G2, and with a glass gauge tube, G3,
to show the height of the liquid in the jars. The parts of this modification not
specially referred to are to be understood to be the same or similar to corres-
ponding parts in the modification first hereinbefore described.
The arrangement described and constituting this modification forms compact.
and easily manipulated apparatus for various purposes, as for example for con-
trolling colored and uncolored lights for scenic effects in a theatre.
In the modification shown in Figures 4, 5, and 6, there are four jars, A1, A2,
A3, A4, of earthenware or other suitable material arranged in a box or casing, M.
Two of these jars, A 1, A 3, will generally be, as shown, smaller than the other

page_text: two, A2, A4, In the bottom of each jar there is a conical metal cup, B'1, B2,
B3, B4, connected through the bottom with an external metal conductor, C,
which is connected to the positive conductor of the main electric supply. In-
each jar, A1, A2, A3, A4, there is a metal cone, C1, C2, C3, C4, each sus-
pended by a non conducting cord, D, which passes more or less round and is in:
each case fastened to the grooved rim of an overhead multiple pulley, N, at such
points in the circumference of the pulley that each suspended cone can reach
the corresponding cup when the pulley is suitably turned as hereinafter described.
The pulley, N, is on a shaft, F, carried by brackets, G, extending up from the
casing, M, and the shaft, F', has on it a sprocket wheel, P, which may be acted
on by a pitch chain, led from any desired point, so as to turn the pulley, N, in
either direction. The cones, C1, C2, C3, C4, are connected each by a flexible-
coil of wire, Q, Figure 5, to three terminals, C2, and C4; to P1, P2, and, C1,
and C3, to P3, connected to separate metal conductors, The wires, Q, from the
two smaller cones, C1, C3, go to one terminal, P3, for the shunt current for a
motor as when reversing the motor the shunt current does not require to be
reversed. The connections from the other two terminals, P1, P2, are through
two contact pieces, Q1, Q2, hinged to a plate, Q5, and projections, Q3, Q4,
on the contact pieces are acted on by a pin, R, on one side of the pulley, N,
so that one of the contact pieces will be lowered into contact and the other
raised out of contact accordingly as the pulley, N, is turned in one direction or
the other as hereinafter described. The plate, Q5, (shown in section in Figure 6).
to which the contact pieces, Q1, Q2, are jointed has connected to it a con-
ductor, Q6, connected to the return conductor of the electric supply. A drain
cock, T, may also be fitted to the jars.
As shown in the drawings the parts of the improved apparatus are in the
position assumed when the motor to which it is applied is being started to run
in one direction. The pulley, N, has been turned in the direction of the arrow
in Figure 5, by the pull of the pitch chain acting on the sprocket wheel, P,
so that one, Ci, of the smaller cones, has been lowered through the liquid in
its jar, A 1, down to its cup, B 1, thus completing the circuit for the shunt cur-
rent for exciting the field magnets. At the same time the pin, R, on the side
of the pulley, N, acting on the projection, Q3, of the contact piece, Q1, has
turned that piece down so as to make contact with the terminal, P2, which has
fixed to it a conductor, P4, connected to the motor and which leads the return
current from the motor through the contact piece, Q1, to the piece, Q5, The
continued movement of the pulley, N, in the same direction then lowers one, C2,
of the larger cones which on touching the liquid in its jar, A2, makes contact
but with some resistance which is slowly diminished as the cone, C2, approaches
its cup, B2, on reaching which the current passes by a conductor, P5, fixed
to the terminal, P1, to the motor. Thus the starting of the motor is effected
gradually and without abruptness and with either a partial or full load.
To reverse the motor the pulley, N, is turned in the direction opposite to that
of the arrow in Figure 5, whereby the cones, 'C1, and C2, are raised out of the
liquid in their jars, A 1, and A2, and at the same time the other two cones, C3, C4,
are lowered through the liquid in their jars, A3, A4, exactly in the manner
described with reference to the cones, C1, C2, the pin, R, on the side of the
pulley, N, at the same time also raising the contact piece, Q1, and lowering
the other contact piece, Q2.
When the pulley, N, has been turned so that the pin, R, is exactly between
the projections, Q3, Q4, on the contact pieces, Q1, Q2, both these pieces will
have been raised out of contact and all the cones, C1, C2, C3, C4, are out of
the liquid. The circuits will then be broken and the motor stopped.
This modification of the improved apparatus is applicable for starting, stop-
ping and reversing motors for hoists, winches, cranes, and the like.
The modification shown in Figures 7, and 8, is an arrangement of the improved

page_text: apparatus in which the cones, C1, C2, are each connected by their non-conduct-
ing cords, D, to separate, overhead pulleys, E, having adjusting handles, E1.
The other parts of this modification not specially referred to are to be under-
stood to be the same or similar to corresponding parts in the other modifications
hereinbefore described.
This arrangement of the improved apparatus is suitable for controlling an
electric current for any purpose as for example for actuating a motor. In starting
a motor the small cone, C1, is first lowered into the liquid and the circuit for
the shunt current for exciting the field magnets is completed when the cone
reaches the cup, B1. Whilst this is being effected the larger cone, C2, is also
slowly lowered and on touching the liquid makes contact but with some resist-
ance which is slowly diminished as the cone approaches the cup, B2. Thus the
starting of the motor is effected gradually and without abruptness and with
either a partial or full load.
If from any cause it is desired to increase the speed of the motor above the
normal this is effected by raising the small cone, C1, which introduces resistance
through the shunt coils and the motor runs faster without any loss.
The motor again may be required to run for short intervals at a slow speed.
This is done by simply raising the larger cone, C2, to suit the required speed.
A switch or equivalent may be introduced into the electric circuits at any
convenient position so that the direction of the currents can be reversed when
both cones are out of the liquid and the circuit broken. This permits of a motor
being driven in either direction as required.
An automatic cut out may also be introduced into the electric circuit so that if by,
any chance the motor should become overloaded the cut out acts and stops the
motor.
Having now particularly described and ascertained the nature of the said in-
vention and in what manner the same is to be performed, we declare that what
we claim is :-
1. In electric contact and resistance apparatus, combining two jars partly filled
with a resistance liquid, and having at the bottom metal cups connected to a
main conductor, with two cones, one in each jar, suspended from opposite sides
of a pulley the turning of which raises one cone and lowers the other, the cones
being connected by wire coils to separate conductors substantially as and for the
purposes hereinbefore described.
2. The combination comprising two or more pairs of jars, each jar being partly
filled with a resistance liquid and having at the bottom a metal cup connected
to a main conductor, also, a horizontal shaft extending above the jars and along
midway between the individual jars of the several pairs, the said shaft having
on it pulleys, one for each pair of jars, also suspended from each side of each
pulley a metal cone which by the turning of the pulley descends or rises in each jar,
the cones being connected to separate conductors, also a handle fitted to each
pulley with means for fixing and loosening the pulley on the shaft, and also
means for turning the shaft and thereby simultaneously turning all the pulleys
on the shaft or as many as are fixed thereon, all substantially as and for the
purposes herein before described.
3. Resistance and contact apparatus for main and shunt electric currents or
the like having in combination four liquid-containing jars in the bottom of each
of which is a conical metal cup connected to the main supply, also metal cones
suspended one in each jar by a cord fastened to a multiple pulley on an overhead
shaft two cones being attached to one side of the pulley and two to the other side
so as to move vertically in opposite directions the cones being also connected by
flexible coils of wire to separate conductors two of these connections being through
hinged contact pieces which can be acted on by a pin on the side of the pulley
substantially as and for the purposes hereinbefore described.
4. In resistance and contact apparatus for main and shunt electric currents or

page_text: the like the combination of two liquid-containing jars in the bottom of each of
which is a conical metal cup connected to the main supply, with a metal cone
suspended in each jar by cords fastened to pulleys on an overhead shaft the cones
being connected by flexible coils of wire to separate conductors and the pulleys
having adjustable handles fitted in connection with them, substantially as and for
the purposes herein before described.
T