Improvements in and relating to Electric Cars and Surface Contact Railways.
Year: 1897

page_text: Date of Application, 14th Sept., 1897-Accepted, 23rd Oct., 1897
COMPLETE SPECIFICATION.
Improvements in and relating to Electric Cars and Surface Contact
Railways.
We, THE BRITISH THOMSON-HOUSTON COMPANY, LIMITED, of 83, Cannon Street,
in the City of London, Electrical Engineers, do hereby declare the nature of this
invention (which has been communicated to us from abroad by Edward M.
Hewlett, of Schenectady, County of Schenectady; State of New York, United
States of America), 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 surface contact railways; and has for its object to
provide for the proper operation of such roads where the car is turned around at
the end of the line."
In turning the car in such systems the contact shoes are reversed in their
relation, to the road contacts. In many cases two sets of contacts are provided,
one furnishing motor current, the other operating the switches, being respectively
on the positive and negative sides of the system. In some of the systems low
potential batteries are also used, being arranged in shunt to the pick-up magnets,
and being charged by the line current working through suitable resistances.
With this form of construction it is necessary that the relation of the battery and
contact shoes be changed when the contact shoes are changed in their relation to
the road contacts, so that the line current will not flow through the battery in the
wrong direction.
One form of device commonly employed in turning the car is the well-
known "Y," and this is selected for illustration herein as a convenient and
conventional arrangement.
To effect the purposes of this invention, an additional or auxiliary contact shoe
is provided besides those commonly provided. In circuit with this shoe is arranged
a magnet coil operating a circuit breaker or switch (of any suitable form) in the
battery circuit. This is placed convenient to the motorman; in addition to it
a reversing switch is provided by which the relation of the contact shoes to the
battery and motors may be changed. The first switch, opening the battery circuit,
is automatically actuated whenever the auxiliary shoe, which forms for this
purpose one terminal of the battery circuit, is grounded. The other terminal of
the battery is also grounded. In the dead space of the Y, which has no working
contacts, is a grounded contact registering with the auxiliary shoe; should the
motorman for any reason omit to break the battery circuit this circuit will be
opened when the auxiliary shoe strikes the grounded contact. The motorman
may then, while the battery circuit is broken, throw the reversing switch above
referred to, changing the relation of the contact shoes, motors and battery. When
the switch in the battery circuit is again closed, the car is ready to operate in
the reverse direction, and by this time will have passed off the dead space in
the "Y" The battery may then be operated to pick up the switches in the usual
way well known in such systems, and therefore not necessary to here describe.
The accompanying drawings show diagrams of arrangements embodying the

page_text: invention; Fig. 1 is a plan of a suitable "Y," Fig. 2 a diagram of the circuits of
a car equipped according to the invention, and Fig. 3 a diagram of a modified
form of the circuits.
In Fig. 1, A, A are the track rails, B, B are the motor contacts, C, C are the
usual switch contacts. The particular form of the "Y" having the extended
contacts ensuring proper registration with the contact shoes is not of the present
invention, and is simply employed as a convenient illustration.
In Fig. 2, A, A, are as before, the track rails, B a motor contact, C a switch
contact; C¹ is an auxiliary or grounded contact for the auxiliary shoe before
referred to. The part of the track represented is the dead space of the "Y" across
which the car is supposed to drift or pass by its own momentum, and. for this
reason the switch contact C and the motor contact B appear on the same side of
the track, though normally they are upon opposite sides, and register respectively
with the positive and negative sliding contacts. This will be understood from
an examination of Fig. 1. D, D are the track wheels, E is the battery, F, F¹ are
the main or ordinary contact shoes, F is the auxiliary contact shoe, C is the
grounding contact. M, M are the motors, R is the motor resistance, R S is the
reversing switch for reversing the contact shoes, F, F¹ with the motors and
battery.
The special switch for opening the battery circuit is indicated at H, and is
actuated by the magnet coil I indicated in circuit with the shoe Fs. At I' is a
blow-out magnet for extinguishing any are which might form from operating the
battery circuit..
In Fig. 3 some of the same parts are shown as in Fig. 2, but in Fig. 2 the
magnet coil I is cut out of the battery circuit by the opening of the switch H.
In Fig. 3 however on examination of the connections will show that this magnet
coil is always maintained in circuit even when the switch H is open.
The operation of the parts just described has been briefly indicated in the
statement of invention. More particularly, however, it is as follows:-
Assume that the car is passing to the right in Fig. 2 that the shoe F is on the
positive side of the circuit, and has been taking current from the motor contact B.
With the switch R S in its illustrated position, this shoe would be grounded as
scon as it strikes the contact C, and if the controller be on, the motors being run
by momentum, would feed current directly into the battery, and as soon as the
shoe F engaged with the motor contact B, towards the right of the figure (not
illustrated) current would pass from that contact also directly through the battery
which would thus be in circuit with but small resistance directly between the two
shoes.
When however the auxiliary shoe F2 strikes the grounded contact C¹, the coil I
is energized and pulls open the switch or circuit breaker H, the blow-out coil I¹
extinguishing any are that may be formed. It is designed to arrange this switch
in the motorman's cab so that his attention will be attracted by the switch opening.
The switch R S is thrown to its dotted line position, thus reversing the relation
of the motors and battery to the shoes F, Fl. The battery circuit being opened,
it is immaterial whether this is done on the dead part of the "Y" or after the
car has passed along further; but as soon as it is done the switch H would be
closed, establishing the battery circuit again, and the car would be ready to
operate in the opposite direction.
Having now particularly described and ascertained the nature of the said in-
vention (as communicated to us from abroad) and in what manner the same is
to be performed, we declare that what we claim is :-
1. In an electric car, the combination of motors, a battery, and contact shoes
connected thereto, with an auxiliary shoe, an automatic switch in circuit there-
with acting to open the battery circuit upon grounding the auxiliary shoe, and a
switch for reversing the leads to the contact shoes while the battery circuit opens.
2. In a surface contact railway provided with means for turning the car, an

page_text: automatic switch for opening the lead from the battery to one of the contact shoes
and a contact in the roadway for opening the switch.
3. The use in combination with an automatic switch actuated by a contact in the
roadway, to open the battery circuit, of a switch acting to reverse the leads between
the motors and battery and the contact shoes.
4. In a surface contact railway provided with a "Y" for turning the car, the Y
having a dead space in which there are no working contacts, a battery, one end of
which is grounded, a switch in the battery circuit, a coil acting to open the switch,
an auxiliary shoe connected to the coil, and a contact in the dead space for
grounding the auxiliary shoe, for the purposes set forth.
Dated the 14th day of September 1897.
J. C. CHAPMAN,
70, Chancery Lane, London, W.C., Chartered Patent Agent.