with Improvements in Electric Switches for use in connection Electrically Propelled Vehicles and Locomotives, and for other Purposes.
Year: 1896

page_text: Date of Application, 24th Nev., 1896
Complete Specification Left. 24th Sept., 1897-Accepted, 30th Oct.. 1897
PROVISIONAL SPECIFICATION.
PROVISIONAL SPECIFICATION.
with
Improvements in Electric Switches for use in connection
Electrically Propelled Vehicles and Locomotives, and for other
Purposes.
We, ALBION THOMAS SNELL, Consulting Engineer, of Suffolk House, Cannon
Street, in the City of London, and CHARLES EDWARD GROVE, Electrical Engineer,
of 11, Cawley Road, South Hackney, and ARNOLD FRANK HILLS, Chairman and
Managing Director of the Thames Iron Works and Shipbuilding Co. Ld., of Orchard
Yard, Blackwall, both in the County of London, do hereby declare the nature of this
invention to be as follows:-
Our invention relates to electric switches chiefly designed for use in connection
with electrically propelled vehicles and locomotives.
In locomotives or vehicles upon electric railways or tramways carrying two, three,
four, or more electric motors, it is usual to provide a switch or series of switches,
with resistances or the like, by means of which the supply of electric current to the
motors may be established or cut off, the speed of the motors may be regulated, and
the direction of running may be controlled. In some cases it is desirable to provide
in addition means by which the mode of coupling of the motors may be varied, as for
instance, in cases where two motors are used, to enable them to be coupled either in
series or in parallel at will.
Our invention consists in the construction and use of a compound switch or series
of interlocked switches especially adapted for operating four electric motors as
hereinafter described, but applicable also with simple modifications to the controlling
of groups of two, three, or more electric motors. In connection with a four motor
equipment we prefer to use three switches in combination. One of these switches,
which may be called the "Starting "switch, controls the supply of current to the
motors or motor armatures by connecting them through a suitable resistance to the
source of supply, the resistance being more or less cut out as the motors attain speed,
and being reinserted and the circuit afterwards broken when it is desired to stop.
The second switch, which may be called the "Controlling" switch, varies the mode
of coupling of the motors or motor armatures so that they may be coupled in any of
the three ways i.e. (a) all four in series (b) in two parallel groupings of two in series
each (c) all four in parallel. The third switch, which may be called the "Reversing "
switch, reverses the connections of the fields or arinatures of the motors with the
source of supply, thereby determining the direction of rotation of the motor armatures
and consequently the direction of motion of the locomotive or vehicle.
These three switches are interlocked in such a way that neither the controlling
nor the reversing switch can be operated unless the starting switch be in such a
position that the supply of current is cut off from the motor armatures, nor can the
starting switch be moved to close or open the electrical circuit unless the controlling
and reversing switches be each in some one of their definite positions determining
the mode of coupling of the motors or of their armatures and the direction of
motion.

page_text: According to one form of our invention the three switches are arranged respectively
upon three shafts parallel to one another the starting switch occupying the central
position and having the controlling and reversing switches one on either side of it.
Each shaft carries upon it, but insulated from it, suitable contact pieces of metal,
which, as the shafts are rotated, engage and make contact with suitably fixed contact
pieces in conducting communication with the motors, resistances, or other parts of
the circuit. The outer fixed contacts may be arranged in the form of parallel rings
or segments of rings or in the form of spirals, the movable contacts being shaped
correspondingly, and they, the outerfixed contacts, are preferably mounted on a
number of blocks of insulating material rather than on one in order to facilitate
removal for renewal or repair.
The contacts of the starting switch, and all metal parts carrying current which are
operated thereby, are preferably enclosed in a separate chamber from the contacts
and current carrying parts of the controlling and reversing switches, so that any
arcing at the contacts of the starting switch may not cause injury to the parts of
the other switches.
Although we have described, our invention as applied in connection with motors
for locomotive or tractive purposes it will be obvious that it may also be used in
connection with a series of motors for other purposes.
Dated this 24th day of November 1806
G. F. REDFERN & Co.,
4 South Street, Finsbury, London, Agents for the Applicants.
Improvements in Electric Switches for use in connection with
Electrically Propelled Vehicles and Locomotives, and for other
Purposes.
We, ALBION THOMAS SNELL, Consulting Engineer, of Suffolk House, Cannon Street,
in the City of London, and CHARLES EDWARD GROVE, Electrical Engineer, of 11,
Cawley Road, South Hackney, and ARNOLD FRANK HILLS, Chairman and Managing
Director of the Thames Iron Works and Shipbuilding Co. Ld., of Orchard Yard,
Blackwall, both in the County of London, 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:-
Our invention relates to electric switches for use upon railways in connection
with electrically propelled vehicles and locomotives.
In locomotives or vehicles upon electric railways or tramways carrying
two, three, four, or more electric motors, it is usual to provide a switch or
series of switches, with resistances or the like, by means of which the supply of
electric current to the motors may be established or cut off, the speed of the motors
may be regulated and the direction of running may be controlled. In some cases it
is desirable to provide in addition means by which the mode of coupling of the motors
may be varied, as for instance, in cases where two motors are used, to enable them to
be coupled either in series or in parallel at will.
Our invention consists in the construction and use of a compound switch or series
of interlocked switches especially adapted for controlling four electric motors as
hereinafter described, but applicable also with simple modifications to the controlling
of groups of two, three, or more electric motors. We prefer to use three switches in
combination. One of them, which may be called the "Starting" switch, controls
the supply of current to the motors or motor armatures by connecting them through

page_text: a suitable resistance to the source of supply, the resistance being more or less cut out
as the motors attain speed, and being reinserted and the circuit afterwards broken.
when it is desired to stop. The second switch, which may be called the "Controlling"
switch varies the mode of coupling of the motors or motor armatures so that they
may be coupled in any of the three ways i.e. (a) all four in series (b) in two parallel
groupings of two in series each (c) all four in parallel. The third switch, which may
be called the "Reversing" switch, reverses the connections of the fields or armatures
of the motors with the source of supply, thereby determining the direction of rotation
of the motor armatures, and consequently the direction of motion of the locomotive
or vehicle.
These three switches are interlocked so that the effects required to be produced by
them shall be produced in an invariable cycle, and it shall be impossible for the
inotor man to operate the switches in such a way as to cause injury to the motors.
Thus current cannot be put into the motor armatures by the starting switch when
the motors are at rest unless the reversing switch is properly set to correspond with
either the forward or backward direction of running, and the controlling switch is set
so as to connect the motors four in series. Contact is male and current admitted
to the armatures for the purpose of starting the locomotive or motor vehicle by
rotating the handle of the starting switch which connects the mains to the motors
through suitable resistances, these resistances being gradually cut out as the handle
is further rotated. At a given point in the cycle current is cut off by the starting
switch and the connections of the motors are changed by the controlling switch from
the combination of four in series to the next combination of two in series and two in
parallel, the circuit is again established by the starting switch through resistance and
as the starting switch handle is further rotated this resistance is again
gradually cut out. At another given point in the cycle the controlling
switch changes the motors from the combination of two in series and two
in parallel to the next combination of four in parallel and resistance is again inserted
and again gradually cut out. Finally the circuit is broken, and the motors connected
four in series ready for the next start, the whole cycle being performed by one
complete revolution of the starting switch handle. The resistances may be reinserted
before each break of the main circuit if desired.
We prefer to arrange that the starting switch shall break circuit just before the
controlling switch changes the notor connections, so that the motor connections
are altered when no current is flowing in their armatures. If it is desired to alter
the direction of running of the locomotive from the forward to backward or vice versa,
the reversing switch is now turned from one position to the other while the
starting switch is in the "stop" position, and the armatures are not carrying
current.
Our invention can be applied in various ways and in the drawings we show by way
of example an arrangement of three switches on parallel shafts adapted for a four-
motor equipment. Each of these shafts carries upon it, but insulated from it, a
number of inetal pieces which, as the shaft is rotated, make contact with suitable
fixed meta! contact parts connected to the motors resistances and other parts of the
circuit; as, however, the construction of these contacts forms no part of our invention
they are shewn in the drawing with as little detail as possible.
In the drawings,-
Figure 1 is a sectional elevation of the three switches with the interlocking gear,
the central switch being the starting switch, that on the left hand side the controlling
switch, and that on the right hand side the reversing switch:
Figure 2 is a plan of the electrical contacts of these switches respectively:
Figure 3 is a diagram of the electrical connections simplified for the present
purpose:
Figure 4 is a plan of the operating handles of the switches:
Figures 5 and 6 show respectively a plan and elevation of the interlocking gear.
Corresponding parts in the several views are lettered and numbered alike.
A A A Are the armatures and E F F F the field magnets of the motors

page_text: respectively, M₁ is the main negative terminal, and M₁+, the main positive
terminal of No. 1 motor, M,-, and M,+ the corresponding main terininals of No. 2
inotor, and so on. T₁, T₁, are the terminals to which the armature of No. 1 motor is
connected through the reversing switch corresponding to say the forward direction
of motion, t, being the terminals to which this armature is connected for say, the
backward direction of motion, T, in the reversing switch, Figure 2, taking the place
of both T, and t, in the general diagrain. Similar sets of connections for the other
motors are also provided in the reversing switch.
RH is the handle of the reversing switch, and s₁, 8, stops limiting the range of
movement of the said handle. K is a squared block upon the handle of the reversing
switch moving between springs which compel it to move quickly from one position to
the other, and prevent it staying in an intermediate position.
CCC are contact bars on the cylinder of the controlling switch which make contact
with the motor terminais M₁, M, etc., in such a way as to couple the motors four in
series. C¹ C¹ are corresponding bars which couple the motors two in series and two
in parallel and C, C are the bars which couple the motors four in parallel.
The
G, and G, are elements of the interlocking mechanism the said elements being a
modification of the well known Geneva stop wheels. The element G, which is the
driver is provided with teeth and the element G, with corresponding recesses.
element or wheel G, has three teeth and the element or wheel G, eight recesses, but
we do not limit ourselves to this numerical relation between the wheels G₁, G. The
wheel G, is rigidly connected to the spindle of the starting switch, so as always to
occupy is definite position in relation to the position of the handle SH. Keyed to
the same spindle as the wheel G, is a toothed wheel W, which engages with a toothed
wheel W, which is keyed to the spindle of the controlling switch. D, is a locking
dise with two segments removed and which is keyed to the spindle of the reversing
switch. D, is a similar disc with one segment removed which engages with the
disc D, in such a way that when the recess in the disc D, is opposite one of the
recesses in the disc D, the reversing switch is free to move from the forward position
to the backward position or vice versu, but in other positions of the disc D, is not
able to do so. The disc D, is rigidly connected to a toothed wheel W, mounted upon
the same axis and engages with the wheel W.
The operation of the apparatus herein before described is as follows,-Let us suppose
that the starting switch is in the "off" position; when, as previously explained, the
locking discs D, and D, will be so situated in relation to one another as to enable the
reversing switch to be operated by the handle RH, that a tooth upon the wheel G¹ is
just emerging from a recess on the wheel G, and that the wheel W, is in such position
that the contact "bars C C C engage with the fixed contacts of the controlling switch
so as to connect the motors four in series as illustrated in column 1 of the contacts
Figure 3. If now the wheel SH of the starting switch is moved through a third of a
revolution it slides over the contacts 1, 2, 3, 4, etc. (of which there may be any
number) and cuts out resistance from the rheostat R, Figure 3, thus bringing a tooth
upon the wheel G, to a position of engagement with the wheel G, and driving the
said wheel through a portion of a revolution less than one third. (With the
arrangement shown in the drawing Figure 5, the wheel G, moves one eighth of a
revolution). The wheel W, also moves through the same angle, but the diameters
of the wheels W₁ and W, are so proportioned that the angular movements of the
wheel W, corresponds with those of the wheel G, and therefore with that of the
wheel SH. Hence the controlling switch is moved a third of a revolution (whereby
the contact bars C', C couple the motors two in parallel and two in series as in
column 2 Figure 3) the current being cut off from the motor armatures just before
the change of connections is made and being re-established immediately afterwards
as previously described. During the movement before described the wheels G.,
and W, owing to the curvature of the surfaces of G, and G, remain fixed in position
being unable to move either backwards or forwards. This state of rest of
the wheels G,, W, and W, continues until the next tooth of the wheel G, engages
with the wheel G₂ when the controlling switch is moved to cause the contact
W

page_text: bars C, C to make contact as shewn in column 3 Figure 3 and connect the four
motors in parallel. The last third of the movement of the wheel G, brings the
wheel W, and consequently the controlling switch to the starting position in which
the four motors are in series after the starting switch has broken the circuit. Thus
when the wheels SH and G, have made a complete revolution the dise D is once
more set free to move and everything is ready to repent the cycle of operations.
RP is a ratchet and pawl arranged to prevent the wheels SH and G, from moving
backwards.
The stop wheels G, G, might be omitted and the motion of the controlling switch
obtained directly from the motion of the starting switch by toothed wheels alone, but
in this case the controlling switch would be continuously moving while the starting
switch is moving, and we think it very desirable to prevent this by the employment
of the stop wheels G, G, so as to allow the controlling switch to have a step by
step movement with intervals of rest. To further facilitate the control of the speed
of the vehicle, the teeth on the ratchet wheel may be removed over those portions of
the circumference corresponding to the periods of rest of the controlling switch, so
that while the controlling switch is at rest upon a given combination the starting
switch handle may be removed either backward or forward to insert or remove
resistance and so facilitate adjustment of speed.
It may be preferred by some persons to vary the windings of the field magnets of
the motors or to wholly or partially short circuit the motors before altering the
combinations by the controlling switch. If this is done additional contacts suitably
connected would be provided in the controlling switch but they are omitted from the
present scheme of connections as being not material to the present invention.
It is to be understood that the spindles of the three switches may be arranged
either vertically or at any other angle also that the handles and locking gear may be
at a distance from the actual contacts and current carrying parts of the switches though
geared with them.
The switch contacts are preferably mounted on separate blocks of marble or other
insulating material arranged to slide between suitably placed guides in the switch
cases, so that they may be separately removable for repair or renewal.
Although we have described our invention as applied in connection with motors for
locomotives or tractive purposes it will be obvious that it may also be used in
connection with a series of motors for other purposes.
Having now particularly described and ascertained the nature of our said invention
and in what manner the same is to be performed, we declare that what we
claim is :-
1. The combination with a switch for opening and closing an electric circuit, of a
second switch carrying two or more series of contacts for the purpose of distributing
the current flowing through the said circuit in various manners through subsidiary
circuits, and of a third switch having contacts for reversing the direction in which
the current flows through the circuits connected with it, the last mentioned switch
being interlocked with the first mentioned switch in such a manner that it can only
be moved when the latter is in the "off" position whilst the second switch is
designed to receive its motion from the first switch through gearing in such a
manner that when the first switch is in a position to allow the passage of a
current through it the second switch is in position to distribute the current through
one or other of its sets of contacts, substantially as described.
2. In a compound electric switch of the kind referred to in the preceding claiming
clause wherein one switch derives its motion from another through the medium of
gearing the provision of means whereby the driven switch shall have an intermittent
motion relatively with the driving switch so as to give periods of rest, substantially
as described.
3. A compound switch comprising a "starting" switch, a "controlling" switch and a
"reversing switch connected together by gearing so as ensure the several switches
being in the proper relative positions for operation, snbstantially as described.

page_text: 4. The manufacture and use of the improved compound electric switch consisting
of the parts constructed and combined substantially in the manner herein before
described and illustrated in the accompanying drawings and operating as, and for the
purposes, set forth.
Dated tha
G. F. REDFERN & Co.,
4 South Street, Finsbury, London, Agents for the Applicants.