Improved Electric Motor-car Switch.
Year: 1897

page_text: Improved Electric Motor-car Switch.
I, OTTO CLAUDE IMMISCH, of 102, Tollington Park, London, N., Electrician,
do hereby declare the nature of this invention to be as follows:-
This invention has for its object an improved switch for electrically driven
vehicles, and provides for the use of a single handle for obtaining different speeds
without those losses hitherto encountered, when for the purpose of varying the
speed, resistances were thrown into the path of the current.
Instead of controlling the speed by wasteful resistances, I provide a set of
auxiliary cells which when it is desired to slow down the speed are put into
opposition to the main current, thereby lowering the E.M.F. of the system in
such a proportion as is easily determined by the number of auxiliary cells
employed, which may be more or less both in number and in capacity, according
to what kind of service the vehicle has to perform.
The second function of the auxiliary cells is that by putting them in series with
the main circuit, they shall assist it to the same degree as they opposed it, when
connected as before described. In other words, when connected up in opposition
to the main circuit, they get charged and their opposing E.M.F. lowers the
tension of the main circuit. When in series they add the energy stored up
in them to the main stock by increasing the tension of the whole circuít
thereby.
Another part of this invention consists in the means provided to make the
necessary changes in the connections, practically sparkless, and otherwise quite
harmless, as regards short-circuiting of the cells.
Hitherto in making a change from a series to a parallel connection or vice versa,
either an injurious spark, or a dead short circuit at the moment of overbridging
occurred.
I am aware that attempts have been made to lessen the latter evil, by dividing
and joining up again through a resistance the movable connecting piece. But
should by any chance the connecting piece be left for any length of time at
the critical position of overbridging, there is always the danger of the resistance
becoming unduly hot. To obviate this drawback I provide at the moment of
overbridging a path for the current to pass round a movable electro-magnet,
which at the moment of being excited moves away from the contacts. There is
.therefore at no time a greater current passing than is just necessary to excite
the magnet. The tendency to spark is reduced to a harmless minimum, and
even should it happen that the switch was left at the critical point of overbridging,
the only inconvenience would be the usual trembling noise of a make and break
arrangement. The noise would be useful to the man in charge of the switch
as indicating that the connector is on the critical position, and a slight movement
in one direction or the other would stop the noise and at the same time save the
current from being wasted.
The general working of the system according to this invention is that by
turning a single handle six varying speeds of the vehicle are obtained. Should

page_text: four speeds be deemed sufficient it is only necessary to leave out two of the contact
pieces.
It should be mentioned that as the auxiliary cells are only required to modify
the speed by adding or opposing their E.M. F., the capacity of these cells need
not be large, and their weight can be small.
Dated this 20th dan
Stambon 1007
ALLISON BROS.,
Agents for the Applicant.
improved Electric Motor-car switch.
I, OTTO CLAUDE IMMISCH, of 102, Tollington Park, London, N., Electrician, 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 this invention are
First, to provide means for varying the speed of electric vehicles driven by
accumulators by the addition of a set of auxiliary cells which when it is desired
to slow down the speed are put into opposition to the main current, thereby
lowering the E.M.F. of the system in such a proportion as is easily determined by
the number of auxiliary cells employed, which may be more or less both in number
and capacity, according to what kind of service the vehicle has to perform.
The second function of the auxiliary cells is that by putting them in series with
the main circuit, they shall assist it to the same degree that they opposed it, when
connected as before described. In other words, when connected up in opposition
to the main circuit, they get charged and their opposing E.M.F. lowers the tension
of the main circuit. When in series they add the energy stored up in them to the
main stock by increasing the tension of the whole circuit thereby.
The general working of the system according to this invention is that by turning
a single handle varying speeds of the vehicle are obtained.
It should be mentioned that as the auxiliary cells are only required to modify the
speed by adding or opposing their E.M.F., the capacity of these cells need not be
large, and their weight can be small.
The second object of my invention is the prevention of injurious sparking in
the switch when the contact is broken in order either to change the connections or
to break the circuit.
For the purposes of this invention the movable switch arm carrying the current
is made in two parts, insulated from each other and so disposed with regard to the
fixed contacts that when one part of the switch arm breaks the working contact,
the other part of the said switch arm lags behind. The two parts being insulated
from each other are joined through the coil of an electromagnet having a movable
core. The core under ordinary working conditions forms part of the main circuit.
When the first mentioned part of the movable switch-arm is moved away from the
fixed contact piece the current passing round the magnet becomes established, and
as the whole available E.M.F. acts on it the magnetic core is powerfully drawn
within its helix thereby breaking the main circuit. The spark which is thus
occasioned does, therefore, not take place in the switch itself but may be shifted to
any other convenient part of the circuit where it can do no harm.
As in carrying out the first object of my invention the mechanical details of a
switch for effecting same would discover no invention inasmuch as the desired
results can be obtained in several ways and by means which are generally known,

page_text: shall confine myself to giving a number of diagrams clearly showing the manner in
which I make the set of auxiliary cells serve my purpose of varying the speed.
The simplest case is that where only three speeds are desired. This is illustrated
in Figs. 1, 2 and 3 of the accompanying drawings, which show the connections and
the direction of the current. In all three diagrams X is the main battery, Y the
auxiliary set, E the movable switch arm, W the motor armature and V the motor
field.
In the position shown in Fig. 1 it is seen that the positive terminal of the auxiliary
cell is opposed to the positive lead of the main circuit, and the E.M.F. of the latter
gets lowered to a proportionate extent. This connection corresponds therefore to
the lowest speed.
In Fig. 2 the auxiliaries are not in circuit and the speed is due to the main
battery simply. Fig. 3 shows that the positive terminal of the auxiliaries is con-
nected to the negative end of the main battery and is, therefore, in series with it.
This corresponds with the highest speed.
The diagrammatic views shown in Figs. 4 to 14 inclusive of the drawings, show
the connections of a switch giving five different speeds.
Figs. 4 to 9 inclusive are diagrammatic views showing the different connections
and circuits when the switching arms occupy different positions, in the case in
which one set of accumulators, one set of auxiliary cells or accumulators, and a
motor with two commutators are employed.
Figs. 10 to 14 inclusive are similar diagrammatic views in the case in which the
main set of accumulators is divided into two halves, and used in connection with a
set of auxiliary cells or accumulators and a motor, with one commutator only.
I will now proceed to describe the circuits established by the switch when in its
different positions, as illustrated in Figs. 4 to 9 inclusive, in all of which the arrows
indicate the course of the current.
In the arrangement, where the motor has two commutators W, W¹, and V
represents the field; X is the main battery and Y the auxiliary cells. Fig. 4 shows
the first position in which the switch arm E is in contact with contact piece 1, and
it will be seen that both the main battery X and the auxiliary cells Y are cut out,
the circuit being closed through contact 1, the field V, the two commutators W W¹
in series, stop 7, the switch arm I, and then back to the arm E.
In the position shown in Fig. 5 the switch arm E is in contact with contact
stop 2, and the circuit is closed through switch arm I, contact 7, commutators W¹ W
(which are still in series), the field V, main battery X, and auxiliary cells Y, which
are opposing the E.M.F. of the main battery, then to stop 2, and switch arm E.
In Fig. 6 switch arm E is in contact with stop 3, and the circuit is through
switch arms E and I, then through the commutators WI W, (which still remain in
series), thence through the field V, the battery X, stops 5 and 6, and so to contact
3, the auxiliary cells Y being cut out.
In Fig. 7 switch arm E is in contact with contact stop 4, and switch arm I with
the contacts 7 and 8, so that commutators W W¹ are in parallel. The circuit is
closed through switch arms E and I, contacts 7 and 8, through the two
commutators W W₁ in parallel, thence through the field, the main battery X,
auxiliary cells Y, which are opposing the E.M.F. of the main battery, and to
contact stop 4.
In Fig. 8 switch arm E is in contact with contact stop 5, and the circuit is through
switch arms E and I, contact stops 7 and 8, and so through the commutators W W¹
in parallel, thence through the field V, main battery X, and so to contact stop 5,
the auxiliary cells Y being cut out.
In Fig. 9 switch arm E is in contact with contact stop 6 and the circuit is closed
through switch arms E and I, contacts 7 and 8, and so through the
commutators W W in parallel, thence to the field V, main battery X, contact
stops 5 and 4, then through the auxiliary cells Y increasing the E.M.F. of the
main battery, and then to stop 6.
The diagrammatic views Figs. 10 to 14 inclusive, show a similar arrangement to

page_text: that last described, but where the motor has one commutator only, while the main
battery is in two portions, which can be connected either in series or in parallel
when desired, instead of connecting the two motor commutators either in series or
in parallel as in the previous case.
In Fig. 10 switch arm E is in contact with contact stop 1 and the circuit is
through such stop to the auxiliary cells Y opposing the E.M.F. of the main
battery, thence through the commutator W, field V, to stops 6 and 7, and so
through the two portions XX' of the main battery, which are in parallel, then to
stops 9 and 8, and switch arm I to switch arm E.
In Fig. 11 switch arm E is in contact with contact stop 2 and the circuit is
through such stop to the commutator W, field V, stops 6 and 7, and so to the two
portions X X of the main battery which are still in parallel, thence to stops 8 and
9 and through switch arm I to switch arm E, the auxiliary cells Y being cut out.
In Fig. 12 switch arm E is in contact with contact stop 3, and the
circuit is closed through such stop to the auxiliary cells Y opposing the E.M.F.
of the main battery, thence through commutator W, field V, and so through
portion X of the main battery, thence through stops 8 and 7, through the other
portion X of the main battery (so that the two portions X X¹ are now in series)
thence to contact 9 and so through switch arm I to switch arm E.
In Fig. 13 switch arm E is in contact with contact stop 4, and the circuit is
closed through such stop to the commutator W, field V, thence through the
portions X X of the main battery (which are still in series), and then by contact 9
through switch arm I to switch arm E, the auxiliary, cells Y being again cut out.
In Fig. 14 the switch'arm E is in contact with contact stop 5, and the circuit is
closed through such stop to the auxiliary cells Y increasing the E.M.F. of the
main battery, thence through the commutator W, field V, and the two portions X'X
of the main battery (which still remain in series), to contact stop 9, and through
switch arm I to switch arm E.
It will be seen that the general working of the system described is that by the
turning of a single handle varying speeds of the motor can be obtained.
It might at first sight appear strange that the connections shown in Figs. 5, 6,
7, 8, 9, as relating to a motor with two. commutators should be different to those
shown in Figs. 10, 11, 12, 13, and 14, in connection with the alternative arrange-
ment of having a divided main battery. A closer study will however show the
reason to be this, that whereas in the former case when both commutators are in
parallel the speed is highest, it is lowest when the two halves of the battery are.
put in parallel. The uniform sequence. of the switch movement necessitates the
difference in connections in both cases as shown.
This part of the invention is obviously also applicable to electrically driven vehicles
having a main electric source other than accumulators.
It should be mentioned that as the auxiliary cells are only required to modify
the speed by adding or opposing their E.M.F., the capacity of these cells need not
be large, and their weight can be small.
Figs. 15 and 16 of the accompanying drawings illustrate a suitable form of
switch for carrying out the second object of my invention, and in such figs. the
switch arm is depicted in that position where the first part of the movable switch
arm E has left the contact piece F, but E (which here is drawn as a disc) still
in connection with Fand fornis the magnetic circuit through D, C, B, the spiral A
back to H. In this position of the switch arm the contact would continue to be
alternately made and broken somewhat in the manner of an electric bell.
noise thus occasioned would warn an attendant that proper working contact was
not established; in practice, however, no purpose.would be served by having the
switch in this position, and the contact pieces being in general closer together than
shown in the drawing, the circuit as a rule is only broken once before it is
established again.
The
My aim has been to attain my object by a cheap and simple device quite as

page_text: efficient in its working as other costly and complicated devices hitherto employed
for the same purpose.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is:-
1. The combination with an electro motor and a main battery for driving same,
of a set of auxiliary cells and a switch with suitable connections to such motor,
main battery and auxiliary cells, so as to enable the speed of the motor to be varied
by causing the auxiliary cells to add or oppose their E.M.F. to the main current, or
by cutting out such auxiliary cells, substantially as specified.
2. The combination with an electro motor having two commutators and a main
battery for driving same, of a set of auxiliary cells and a switch with suitable
connections to such motor, main battery and auxiliary cells, so as to enable the
two commutators to be placed either in series or in parallel and for cutting out,
introducing and connecting the auxiliary cells with the main battery, whereby the
E.M.F. of such auxiliary cells will either assist or act in opposition to the main
battery, all substantially as described and for the purpose of varying the speed
of the motor as desired.
3. The combination with an electro motor having a single commutator, of a main
battery divided into two portions, a set of auxiliary cells and a switch with suitable
connections to such motor, the two portions of the main battery and auxiliary cells,
so as to enable the two portions of the main battery to be placed either in series or
in parallel, and for cutting out, introducing and connecting the auxiliary colls with
the main battery, whereby the E.M.F. of such auxiliary cells will either assist or
act in opposition to the main battery, all substantially as described and for the
purpose of varying the speed of the motor as desired.
4. The combination with a motor car switch of a contact piece in addition to the
ordinary contact piece for making and breaking the circuit, and an electro magnet
with movable core suitably connected with such additional contact piece and the
main circuit, so that at the time the ordinary contact piece of the switch breaks
the circuit the additional contact piece lags behind and opens a path for the current
through the electro magnet, and thus prevents injurious sparking at the ordinary
connections of the switch, all substantially as specified.
Dited this 15th day of Tune 1000°