Improvements in Surface Contact or Closed Conduit Electric Railway Systems.
Year: 1897

page_text: Date of Application, 7th Sept., 1897-Accepted, 13th Nov., 1897
COMPLETE SPECIFICATION.
Improvements in Surface Contact or Closed Conduit Electric Railway
Systems.
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 William B.
Potter, 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:-
The invention relates to electric railway systems, sometimes called closed con-
duit systems or surface-contact systems, and characterized by the presence of
sectional conductors or contacts normally disconnected from the source of supply,
and electro-magnetically, operated switches which complete a circuit between
the sectional contacts and a feeder or distributing main in sequence for supplying
current to the travelling motor or motors. For ordinary street railway work
sectional contacts are arranged on the surface of the street. Of course, the inven-
tion is applicable to elevated railway service or systems where the sectional con-
tacts are housed in a conduit, or arranged in any other desired manner.
The invention relates more particularly to what are sometimes called shunt
systems, that is, systems where the line switches are picked up by magnets whose
coils 1orm part of a shunt circuit around the motor, and hence receive the full
line potential. It is intended particularly to devise a system such that the cars
may run equally well in both directions, also to provide a sufficient overlap,
or time allowance, in order that the circuits may be maintained operative at high
speed, and to simplify as much as possible the arrangement of the surface contacts
and travelling collectors, as will be more particularly described hereinafter.
The invention is illustrated in the accompanying drawing, wherein is shown
a diagram of an electric railway system embodying the improvements.
to as
66
In this figure A, A are the track rails, B, B and C, C are the sectional conductors
or contacts. These may be points or rails, as is now well understood in the art,
though the use of points is preferred. The contacts B are hereinafter referred
motor contacts," because they form part of the circuit through the car
"switch contacts," since these
motors, and the contacts C, C are referred to as
are provided for completing the shunt circuit through the switch-operating
magnets. F represents the shoe or collector which makes sliding contact with
the motor contacts B, and is connected to one terminal of the motors M, M, the
other motor terminal being grounded upon the car wheels and axle D. E is a
storage battery carried by the car which is connected in multiple with the motors
between the shoe F and ground, and serves to pick up the switches when the line
current is not operative for this purpose. The magnet coils 9' are connected
between switch contacts C and the rail A and are of comparatively high resist-
ance, since they form part of a circuit shunting the motor and hence receive the
full line potential. The line switches G, G¹, G are closed by the magnets and

page_text: opened by gravity, or in any other desired manner. Blow-out coils b b are
included in circuit between the motor contacts B and the contacts at the line
switch. The motor contacts B are connected with the line switches in pairs, as
shown in the diagram, so that when any given switch is closed two of the motor
contacts are thereby connected in multiple with the feeder or distributing
main H, and likewise, it will be observed, that each of the motor contacts B is
connected to contacts at two of the line switches, so that it may be connected
to the feeder through either or both of the line switches, as will be understood
from an examination of the diagram. As the car advances, the motor contacts
are successively connected with the feeder slightly before they are reached by
the travelling shoe F and each motor contact is connected first through one of the
switches, then a second connection in multiple with the first is established through
a line switch next in advance, and finally, the first established connection is
broken while the motor contact still remains energized from the second switch,
so that in the practical operation of the system each motor contact is energized
for a longer interval of time, than the interval during which the switches indi-
vidually considered are held closed. In this way an efficient time overlap is
secured without making the collectors unduly long, and at the same time allow
the placing of the contacts as far apart as possible.
The motor contacts are shown arranged in a central row between the track rails,
while the switch contacts C, C are shown outside the rails, and the contacts C, C
are staggered with reference to the motor contacts B, B, since it is found that
much better results can be secured in this way than are possible if the switch
contacts and motor contacts stand directly opposite one another. A second
collector shoe F rides upon the switch contacts C C and is electrically connected
with the shoe F. With the parts arranged as shown in the diagram the switch G¹
is closed, the shoe F bridges two of the motor contacts B, B, and current may
pass through both of these contacts to the motors and ground through wheels D.
The shunt circuit around the motor leading from the collector F through the
shoe F, switch contact C, and high potential magnet coil g to ground, holds
the switch G' closed. As the car advances in the direction of the arrow, the
shoe shortly reaches the next switch contact C in advance, before it breaks
contact with the one which it is shown resting upon, and establishes a circuit
through the magnet of switch Gs, closing this switch and connecting a new
motor contact with the feeder. If the motor circuit is interrupted at any time or
the line current fails to operate in picking up the switches, the battery is used
to close one or more of the switches and so start the system in normal operation.
The circuit of the battery leads through the magnet coils g and is completed
through the ground, as will be readily understood from the diagram.
blow-out magnet coils bb prevents damage to the switches by extinguishing
arcs in a well-known way, though there should be no serious are at the switches
in any event.
The
Having now particularly described and ascertained the nature of the said inven-
tion (as communicated to us from abroad) and in what manner the same is to
be performed, we declare that what we claim is :-
1. An electric railway system provided with sectional normally-insulated con-
tacts, a feeder, switches for connecting the sectional contacts in sequence with
the feeder, and electro-magnets operating the switches having a pick-up coil in
shunt to the motor circuit, each switch energizing a plurality of surface contacts
carrying motor current, and each motor contact taking current from more than
one of the switches.
2. In an electric railway the combination of a feeder, two rows of staggered
sectional contacts, high-potential magnets grounded at one terminal and con-
nected at the other terminal to one row of contacts, switches controlled by said
magnets connecting the feeder directly with the other row of contacts and collectors
on the car which, when the system is in operation, bridge adjacent contacts in

page_text: each row alternately, and establish a circuit through the magnets in shunt to
the motor circuit.
3. In an electric railway the combination of a feeder, sectional motor contacts,
switches corresponding in number with the motor contacts, electrical connections
by which each motor contact may be connected to line through two of the switches,
each switch engaging at least two contacts, and electro-magnets for operating
the switches having a pick-up coil in shunt to the motor circuit.
4. In an electric railway system the combination of a feeder, motor contacts
forming part of the motor circuit, switches each having contacts by which a
plurality of said motor contacts, adjacent to one another, are connected with
the feeder in multiple, and electro-magnets controlling the switches provided
with a pick-up coil in shunt to the motor circuit.
•
100K
5
For the Applicants,
J. C. CHAPMAN,
70 Chancery Lane, London, W.C., Chartered Patent Agent.