Improvements in Four Motor Reversing Switches.
Year: 1895

page_text: Date of Application, 30th July, 1895-Accepted, 8th Feb., 1896
COMPLETE SPECIFICATION.
Improvements in Four Motor Reversing Switches.
I, JAMES DEVONSHIRE, Secretary to The British Thomson-Houston, Limited,
of 38, Parliament Street, Westininster, in the County of Middlesex, (a com-
munication to me from abroad from Frank E. Case, of Schenectady, in the County
of Schenectady, State of New York, United States of America, Electrical
Engineer), do hereby declare the nature of this invention and in what manuer
the same is to be performed to be particularly described and ascertained in and
by the following statement :-
The present invention is an improvement upon the construction of that kind of
series parallel controller which is adapted to operate two motors in the various
combinations of series and parallel, with a resistance. This has been effected by
first connecting the motors in series with a resistance, and then cutting out the
resistance; then reinserting the resistance and shunting one of the motors, and
then throwing the motors into multiple and cutting out the resistance. Also inter-
locking mechanism has been used between the reversing switch and the controller
cylinder, and so arranged that each of these switches may only be operated when
the other is in a predetermined position, by which means arcing at the contacts is
limited; the predetermined position of the controlling switch is the off position, in
which no current flows; and a predetermined position of the reversing switch is
that in which the motors are connected to run either forward or backward, as may
be desired.
The object of the present invention is to adapt such a form of controller for use
with either two or four motors without changing the construction to any marked
degree. the only change necessary being in the reversing switch, and to this is
added an extra set of contacts and brushes bearing thereon, the contacts being so
situated on the switch cylinder that the cross-connected ones are common to both
the existing and the added brushes; and furthermore this may be used for a regular
two-motor equipment by simply leaving the added brushes open-circuited; this is
an advantage where a controller is sent out for a two-motor controller, and it is
found desirable to have four motors instead.
By such a construction the controller is adapted to run four motors and by the
use of cut-out switches two of the motors may be cut out, as in the case of accident,
and in that event the remaining motors are connected in parallel with each other
and in series with the resistance which may be gradually cut out and in by suitable
contacts and brushes on the controller.
In the series-parallel control of railway motors it has been found desirable to
divide the notors up in such a manner as to have at least one active motor on each
truck for the purpose of obtaining the maximum tractive effect of the motors while
changing from series to parallel, whereby the car is driven more equally than it
would be with other arrangements.
In the present invention the motors are permanently connected in pairs, and the
pairs of motors are treated as though they were single motors, that is, in changing
from series to parallel the two motors forming one pair are thrown in parallel with
the second pair, and they are so mounted that one of the first pair is on the same
truck with one of the second pair.

page_text: In the accompanying drawing,
Fig. 1 is a plan view, partially in section, of my improved apparatus ;
Figs. 2 and 3 are diagrammatic views illustrating the operation thereof.
A is the back of the controller to which are secured by suitable means the various
parts thereof.
B is the enclosing case made of any suitable material and fitting
into a groove C on the back of the controller.
The reversing switch cylinder D is ma le of insulating material, such as wood or
fibre, upon which are mounted three sets of contacts 9.9', g² occupying less than 180°
of the circumference of the cylinder. By mounting the contacts on the cylinder D
in the manner described, the motor-man is enabled to reverse his motors quickly,
and by a small angular movement of the reversing handle, which is an advantage
on a crowded car where the space is very limited. It also permits the brushes to
be placed near together and in an accessible part of the controller. The switch is
revolubly mounted on the shaft E, which is provided with suitable bearings, not
shown for clearness of illustration. 1, are cables leading from the motors and
resistance boxes. The brushes, of which there are two sets, are mounted on blocks
of wood F F, and these are secured by any suitable means.
The brushes f, f¹
are made of pieces of copper and pressed into engagement with the rows of
contacts g, g', g2 by springs h, h¹. Stops i, i are provided to limit the movement
of the brushes f, f¹.
Referring now to Fig. 2, which shows the invention in its simplest form, it will
be seen that the motors M', M³ form a pair and are reversed by the contacts at the
lower part of the cylinder, the cross-connected contacts r, k, j, I being arranged in
a lower series and connected so as to form pairs. The motors M3, M4 also form a
pair, and are reversed by the upper series of contacts m, n, o, p, also connected so
as to form pairs.
If for any cause motors M³, M were disabled an 1 the brushes raised so as not to
make contact with the cylinder, the same condition of affair- would be had as
obtains in the kind of motor first above referred to, and it will now be evident that
to utilize this controller for four motors, a single row of brushes and contacts is
added, the rest remaining the same.
The operation of the device will now be described. Assuming that the brushes
are on the rows of contacts g¹, 92, which position corresponds with that shown in
Fig. 1, the circuit would be as follows:
The current entering the wire a would divide at the point b and the path through
the motor M' would be through contact r, cross-connection to contact k, through
the armature to contact j, cross-connection to contact 7, through the field to
contact m. Going back to the point where the current first divided, the second
path would be by contact d', through the armature of motor M³, to contact e¹,
through the field to contact t¹, where it unites with the current from motor M' by
means of cross-connection 15; continuing the circuit it divides again at this point,
flowing through motor M2, by way of contact m, cross-connected to contact o,
through the armature to contact n, by cross-connection to contact P thence through
the field to ground; the circuit through motor M would be from 15 through
contact to the armature of the motor, contact h¹ through the field to ground.
The direction of the current in the armature is indicated by the arrows.
Assume now that the position of the contacts has been shifted relative to the
brushes and that the latter are now resting on rows of contacts g, g¹, then the
current entering by wire a would divide at b and again flow through the motors by
means of contacts, as explained above, but the current flowing in the armatures
will be reversed, as indicated by the dotted arrows.
Referring now to Fig. 3, it will be seen that motors M', M³ and M³, M* are
permanently connected together, and the connections with the cut-out switches J, J
are so arranged that the opening of either switch cuts out of circuit a pair of
motors.
The connections from the switches to the controlling cylinder are not shown, for
it is immaterial what form of controller is used.

page_text: Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
1. The combination in a reversing switch, of a row of contacts adapted to be
connected to line in either position of the switch, and two or more rows of contacts
and brushes, each one leading to and adapted to reverse one or more motors.
2. As an article of manufacture, a four motor reversing switch cylinder having
three rows of contacts, the middle row being cross-connected relative to each other,
the outer contacts being wide enough to engage with two brushes, the middle
contacts with one.
3. In a four motor reversing switch, the combination of three rows of contacts
mounted on a cylinder, with two sets of brushes, one set leading to one pair of
motors and the second set to a second pair of motors, engaging with the contacts,
one row of contacts being common to both sets of brushes.
4. In a four motor reversing switch, the combination of three rows of contacts
mounted on a cylinder with two sets of brushes making contact therewith, the
middle and one set of outer contacts being connected so as to cause the motors to
revolve in one direction, and the middle and remaining outer contacts causing them
to revolve in the opposite direction.
5. In a four motor reversing switch, the combination of three rows of contacts
mounted on a cylinder, two sets of brushes engaging therewith, the outer contacts
engaging with two brushes, the inner contacts with one, the inner contacts being
arranged in an upper and lower series, each series consisting of pairs of contacts
cross-connected, the said series of contacts being common to both sets of brushes.
6. In a four motor reversing switch, with the motors connected in pairs, the
combination of three rows of contacts, brushes making contact therewith, the inner
contacts being arranged in an upper and lower series, the contacts in the series
being arranged to form pairs, the leads from two of the motors which form a pair
going to the lower series, and those from the remaining pair going to the upper
series.