Improvements in Switches for Connecting Two or More Electromotors.
Year: 1895

page_text: Date of Application, 14th Dec., 1895
Complete Specification Left, 2nd Sept., 1896-Accepted, 14th Dec., 1896
PROVISIONAL SPECIFICATION.
PROVISIONAL SPECIFICATION.
Improvements in Switches for Connecting Two or More
Electromotors.
We, SIEMENS BROTHERS & Co. LIMITED, of 12 Queen Anne's Gate, West-
minster, in the County of London, and ALBERT THOMAS BARTLETT, of No. 8
Fairfield Road, Old Charlton, in the County of Kent, Electrical Engineers, do
hereby declare the nature of this invention to be as follows :—
This invention relates to the construction and arrangement of switches by which
two or more electric motors can be connected with a source of electricity in various
successive conditions such for instance as those suitable for starting an electrically
propelled car. Switches of multiple contact type, such as are usually employed
for this purpose, present the disadvantage that in passing from one coudition of
the circuits to others there are breaks of circuit causing sparking or formation of
arcs, which seriously damage the switches.
Our invention has for its object to avoid this evil, which we effect by employing
a switch having contact arms worked not simultaneously but in due succession by
the movement of one controlling handle. When there are two motors, the switch
has two arms.
As neither of these arms makes more than two contacts, it can
have a long and yet a rapid break, and may be provided with carbon breaks, so
that it can effect change of circuit without damage.
The two arms and contacts are arranged as follows:-The one arm in its one
position makes a contact connected with no circuit, in its other position it makes a
contact connecting it to the minus terminal of the source of electricity; it is
always connected to the minus terminal of the first motor, the other arm which is
always connected to the plus terminal of the second motor, in its one position makes
a contact connecting it with the minus terminal of the first motor, in its other
position it makes a contact connecting it with the plus terminal of the source of
electricity.
By moving these two arms to their several positions the two motors (1) can be
connected in series (2) can have one short circuited, (3) can have one cut out of
circuit (4) can be connected in parallel.
Each contact is preferably provided with a spring so arranged as to hold the
arm with a certain amount of friction, so that the arm which is itself elastic is bent
before the contact spring releases it, and when it is released it springs rapidly out
of contact. An arm on a spindle turned by a handle acts on the two contact arms
successively, and on this spindle there is preferably another arm carrying a brush
which passes over a number of circularly arranged contacts connected to resistances,
so that according to the conditions of the motor circuits determined by the
movements of the switch, suitable resistances are simultaneously introduced into
them.
When more than two motors have to work together as in propelling a car,
several switches of the kind described are arranged to be operated by the one
handle.
100
ABEL & IMRAY,
Agents for the Applicants.

page_text: Improvements in Switches for Connecting Two or More
Electromotors.
We, SIEMENS BROTHERS & Co. LIMITED, of 12 Queen Anne's Gate, West-
minster, in the County of London, and ALBERT THOMAS BARTLETT of No. 8
Fairfield Road, Old Charlton, in the County of Kent, 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:-
This invention relates to the construction and arrangement of switches by which
two or more electric motors can be connected with a source of electricity in various
successive conditions such for instance as those suitable for starting an electrically
propelled car. Switches of multiple contact type, such as are usually employed
for this purpose, present the disadvantage that in passing from one condition of the
circuits to others there are breaks of circuit causing sparking or formation of arcs
which seriously damage the switches.
Our invention has for its object to avoid this evil, which we effect by employing
a switch having contact arms worked, not simultaneously, but in due succession by
the movement of one controlling handle. When there are two motors, the switch
has two arms. As neither of these arms makes more than two contacts, it can'
have a long and yet a rapid break, and may in addition be provided with carbon
breaks, so that it can effect change of circuit without damage.
-
-
The two arms connections and contacts of such a double switch suitable for two
motors may be arranged as shown in front view by Fig. I and diagrammatically
by Figs. 2, 3, 4 and 5 of the accompanying drawings. The one arm A which is
always connected to the terminal of the first motor in its one position as at A
makes a contact a by which it is connected to the terminal of the source of
electricity. In its other position, as indicated by the dotted lines at A', it makes
a contact a' which is not connected to any circuit. The other arm B which, is
always connected to the + terminal of the second motor, in its one position as at B
makes a contact 6 connecting it to the + terminal of the source of electricity; in
its other position, indicated by the dotted lines B', it makes a contact 6' connecting
it to the terminal of the first motor. By moving these two arms to their several
positions by means of a handle H moving over a suitably marked semi-circle S,
the two motors can be connected in series, or one of them can be short circuited,
or one can be cut out of circuit, or both can be connected in parallel. Each arm
carries a metal contact piece c which when making contact is thrust in between a
pair of spring plates provided at a a' bb, which hold the contact piece with a
certain degree of friction. In order to prevent sparking on the separation of the
metal contact pieces c from the contact springs ab and b¹ these parts may be
furnished with spring mounted carbon contacts, which can be easily renewed as set
forth in the Specification No. 8448 of 1884. The arm itself is pivotted at the
centre of a disc D so as to be free to move a little between a pair of stops d
fixed on the disc. A blade springs similar to that described in the Specification
No. 1924 of 1892, has its one end fixed at ¹ to the arm, its other end fixed at s
to the disc D. Each disc has a notch N and on each side of it a circularly curved
hollow Th On the axis of the handle H is fixed another disc T having a tooth't
with a hollow on each side of it. When, by turning the handle. H, the tooth t is
made to engage in the notch N of one of the discs D, its first effect, as it moves
onwards, is to partly turn the disc and thereby bend the spring a, the arm being
held stationary by the friction of the contact piece a between the contact springs.

page_text: But when the disc D is thus so far turned that one of the stops d bears against.
the arm,
then the contact piece is moved to a certain extent from between the
contact springs, and, the arm, being thus to a certain extent released, is caused.
by the effort of the spring to straighten itself, making a rapid break of the
contact. When the tooth thas turned the disc D until it has escaped the notch N,
the engagement of the disc T in the hollow n of the disc D retains the disc D
firmly in the position to which it has been moved. Along with the handle H a.
brush or rubber may move over contacts connected to suitable resistances, which,
may be thus introduced into or cut out of the circuits determined by the position of
the arms A. B. In order that the movements of the arms and of the brush or
rubber may occur in proper sequence in whichever direction H is turned, it is
necessary that there be a certain degree of play in the connection between the
handle H and the brush or rubber, equivalent to the angle through which H turus.
whilst simply bending the blade spring before the arm is moved positively by the
stop d.
Obviously several other discs such as D may be arranged around the handle-
disc T either in the same plane or in different planes, so that the action of more.
than two motors may be controlled by a single handle.
Having now particularly described and ascertained the nature of this inven--
tion and in what manner the same is to be performed we declare that what we.
claim is :-
A switch for connecting two or more electromotors, wherein two or more arms.
are moved separately and successively from one contact position to another, by
means of a handle having on its axis a disc which engaging in hollows of discs.
to which the arms are attached, holds them firmly in the positions to which
they are respectively turned by means of a tooth of the handle disc, substantially
as described.
1
1000
ABEL & IMRAY,
Agents for the Applicants..