Improvements in Automatic Switches, and in their Use for Distribution of Electricity.
Year: 1895

page_text: Date of Application, 29th Jar., 1895
Complete Specification Left, 29th Oct., 1895-Accepted, 29th Jan., 1896
PROVISIONAL SPECIFICATION.
Improvements in Automatic Switches, and in their Use for
Distribution of Electricity.
JOHN HOPKINSON, F.R.S., of 5 Victoria Street London, S.W., do hereby
declare the nature of this invention to be as follows:-
My invention relates to the class of switch which forms the subject of my Patent
No. 22876 A.D. 1893, to which I hereby refer. It renders the switches adequate
for use for distribution of electricity from central sources of supply.
I make use of an electromagnet or electromagnets the wire of which is connected
to the terminals the difference of potential between which determines the motion
of the switch. I so construct the electromagnet that its equilibrium when resting
against a stop is essentially unstable that is so that when once it begins to move it
moves with considerable energy to a position in which it makes a contact of
considerable firmness in another circuit. I reset the electromagnet by the
movement of parts connected to the switch actuated by the agency of the electro-
magnet. I either short circuit the electromagnet or break its circuit or increase
the resistance of its circuit if the electromagnet is to operate when a rising pressure
attains a standard value or if the electromagnet is to operate when a falling
potential reaches a standard value I diminish the resistance of the electromagnet
circuit or in some way increase the current through it also by the movement of
parts connected to the switch. In this way I cause the switch to move one step
only and a complete step in the desired direction and reset the electromagnet ready
to take the next step when the proper time arrives. The circuit which is made by
the action of the electromagnet may lead through the armature of a dynamo
machine or may lead through an electromagnet which releases a catch or brake
and permits the switch to move under the action of a weight or spring.
In order to give greater security to the action and to avoid sparking at the
contact actuated by the clectromagnets I cause the movement of the switch to
make a contact short circuiting the contact on the electromagnet in every position
except positions near the positions in which it is appropriate the switch should rest.
This may have the form of a screw on a shaft and two contacts arranged in
such wise that if the shaft revolves in one direction one contact operates, if in the
other direction the other contact. I may also diminish sparks by a condenser
connected to the two sides of the contact.
In applying battery switches of the class to which those herein described and
those described in my Patent No. 22876 of 1893 belong to central station
distribution, I connect feeders through an automatic charging switch to the battery
which may be remote from the place where the current is generated and I connect
the battery to distributing mains through an automatic discharging switch. I am
thus able to obtain good regulation of pressure a long slow charge of the battery
with consequent economical transmission to longer distances and the advantages of
storage of electricity without additional cost for labour of attendance. Suppose a
number of battery feeders are connected to the same generating machine that
battery, ceteris paribus, which most charged will take the largest current because
the smallest number of cells is connected through the charging switch but this will
be known at the generating station from the current in the feeder and the potential
at the generating station and can be adjusted by known means.

page_text: I arrange that when the charging of the battery is completed the feeder circuit is
automatically broken either by the potential of the battery or of the end cell therein
or I arrange that the charging switch resets itself by a continued motion to the
maximum number of cells when the feeder circuit can be broken by hand at the
generating station.
Dated this 20th day of January 1005
Improvements in Automatic Switches, and in their Use for
Distribution of Electricity.
I, JOHN HOPKINSON F.R S. of 5 Victoria Street London, S.W., 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:
My invention relates to the class of switch which forms the subject of my Patent
No. 22876 of 1893, that is, to battery switches and to switches moving by definite
steps.
It is essential in battery switches that if the switch be moved at all, it shall move
a complete step from one cell to the next and not rest in an intermediate position.
To attain this I make use of an electromagnet or electromagnets the wire of which
is connected to the terminals the difference of potential between which is to
determine the motion of the switch, for example, in a charging switch the next cell
to be cut out, in a discharging switch the terminals of the conductors supplying
the lamps. I so construct the electromagnet and its armature that the equilibrium
of the armature when resting against a stop is essentially unstable, that is, so that
when once it begins to move, it moves with considerable energy to a position in
which it makes a contact of considerable firmness in another circuit, and has power
to move light mechanism with certainty. I reset the electromagnet by the
movement of parts connected to the switch actuated by the agency of the electro-
magnet. I either short circuit the electromagnet or break its circuit or increase
the resistance of its circuit if the electromagnet is to operate when a rising pressure
attains a standard value, or if the electromagnet is to operate when a falling
potential reaches a standard value I diminish the resistance of the electromagnet
circuit or in some way increase the current through it also by the movement of
parts connected to the switch. In this way I cause the switch to move one step
only and a complete step in the desired direction and reset the electromagnet ready
to take the next step when the proper time arrives. The circuit which is made by
the action of the electromagnet may lead through the armature of a dynamo
machine or may lead through an electromagnet which releases a catch or brake and
permits the switch to move under the action of a weight or spring.
In applying battery switches of the class to which those herein described and
those described in my Patent No. 22876 of 1893 belong to central station
distribution, I connect feeders through automatic charging switches to the battery
which may be remote from the place where the current is generated, and I connect
the battery to distributing mains through an automatic discharging switch. I am
thus able to obtain good regulation of pressure, a long slow charge of the battery
with consequent economical transmission to longer distances, and the advantages
of storage of electricity without additional cost for labour of attendance.
In order that my invention may be better understood I will now describe it with
reference to the accompanying drawing. This drawing and description disclose
improvements which I have made since the date of my present invention, but they
are herein described as they embody the method best known to me for carrying

page_text: out the invention. They are not claimed herein as they are not indicated in my
Provisional Specification, but it is my intention to claim them in a Patent of later
date No. 9286 dated 10th May '1895. The drawing shows the arrangement of
electromagnets suitable for a discharging switch, actuated by an electromotor.
The electromagnet C determines the action of the switch when the number of cells
is to be increased on account of the potential of the battery becoming too low.
The electromagnet D determines the action of the switch when the number of
cells is to be decreased on account of the potential of the battery becoming too
high.
In order to avoid disturbing effects from mechanical vibration, these switches
are carried upon springs E from which they are freely suspended and the electrical
connections are made by coils of wire through which no vibration can pass. The
armatures F of the electromagnets each rest normally upon three adjusting
screws G arranged to give a geometrical support on the cone, slot and. plane
system or other equivalent system.
Referring to the electromagnet C, it is clear that when the attraction of the
magnet diminishes to a poiut at which the armature leaves points of support that
the attraction of the magnet for the armature will greatly diminish as the armature
becomes more moved from the magnet and that therefore when the armature drops
upon the contact screws H, it will make a good electrical contact between the two
screws. The screws H H are connected with the poles of the motor machine
indicated diagrammatically at P and with one or more cells of a battery indicated
diagrammatically at Q in suchwise that when contact is made between them, the
armature of the electromotor will revolve in one direction. The corresponding
screws I 1 of the other electromagnet are connected with the armature of the motor
and with other cells R of the battery in such wise that when contact is made
Ietween them the armature will revolve in the other direction. One of these two
circuits, say that of the electromagnet C is carried round the other electromagnet
by a supplementary coil S, so that if the electromagnet C operates the magnetism.
of the electromagnet D is diminished by a current circulating through the supple-
mentary coil S and it is thereby secured that if the electromagnet C is operating,
the electromagnet D cannot operate until the operation of the electromagnet C is
completed.
The main coils of the electromagnet C & D are normally connected to the main
conductors of supply A & B, but they are so connected through the switch K
which moves with the main switch which it is the intention of the apparatus to
operate. This switch K has bearing upon it three contact springs L, M, N, and
in turning, it moves through a complete period of its changes when the main switch
advances by a complete step. The shaded parts of this switch K indicate
insulating material, the non-shaded parts indicate conducting material. If the
main switch moves in a direction to diminish the number of battery cells connected,
the switch K moves in the direction indicated by the arrow.
On inspection of the drawing it will be observed that when the number of cells
becomes too great, the armature F of the electromagnet D will rise, will make.
contact between two of the screws I I, and the main switch will move in a direction
to diminish the number of cells. When its motion is nearly completed, the circuit
of the electromagnet will be broken by the insulated part O and the armature F
will then drop into its initial position ready to give or refuse to give a further signal
as may be required. On the other hand if the number of cells becomes too few the '
armature of the electromagnet C will fall and will make contact between two of
the screws HH; a current will then pass and will cause the main switch to
operate. Near the end of the time of its operation the contact pieces L M of the.
switch K will be short circuited, and will so short circuit the resistance r and
increase the current through the coils of the electromagnet C thereby causing
the armature F of this electromagnet to be raised into its normal position.
It is obvious that the details of this apparatus may be varied materially The
armatures instead of making contact may operate mechanically to take off brakes

page_text: and allow the apparatus to work. The insulating part O may be replaced by a
conducting part as on the other side of the switch, which shall have the effect of
short circuiting the electromagnet D instead of breaking its circuit. I have
described the best method known to me of carrying out my invention.
It is also clear that my construction of electromagnets and methods of operating
same may be applied to other apparatus, in particular to taking out an ordinary
resistance and putting it into a circuit: For this purpose with continuous currents
my apparatus is applicable without alteration. It may also be applicable to arc
lamps and various apparatus with alternating currents, but I wish to limit my
claim to the application of the switches to the charging and discharging of
accumulators and to switches moving step by step to introduce or take out a
resistance from an electrical circuit, as these are the only applications which I have
hitherto worked out.
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 :-
An automatic electric switch moving by steps to introduce or take out batteries
-or resistance the said switch being regulated by an electromagnet the armature of
which is reset by altering the current through the coils of the electromagnet by
means of a part moving with the switch.
Dated this o0th 1
1005
J. HOPKINSON.