Improvements in and relating to Closed Conduit or Surface Contact Electric Railways.
Year: 1897

page_text: Date of Application, 7th Sept., 1897--Accepted, 13th Nov., 1897
COMPLETE SPECIFICATION.
Improvements in and relating to Closed Conduit or Surface Contact
Electric 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 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 present invention relates to electric railways, sometimes called "surface-
contact" railways or "closed-conduit" railways, in which the motor circuit is
completed through a series of normally insulated sectional contacts which are
brought into electrical connection with a feeder or distributing main through
electro magnetic switches closed in sequence as the car travels over the line.
Herein are set forth certain improvements in a system of this character, the
cbject being to provide a system in which the number of sectional contacts is
kept as small as possible, also one in which the cars may move with equal facility
in either direction, whether they are turned around at the end of the line or not;
and one in which a sufficient overlap or time allowance is secured without increas-
ing unduly the length of the contact shoe.
The means devised for these purposes and constituting the present improve-
ments are hereinafter set forth in detail and are illustrated in the accompanying
drawings, wherein Fig. 1 is a diagram of a railway system embodying the inven-
tion; Fig. 2 is a diagram of a similar system with certain additional features;
Fig. 3 is a detail view of an improved contact shoe for use in electric railway
systems of this general character, and Fig. 4 a diagram of a railway system with
still further modifications.
In the diagrams, A, A are the track rails, B, B are insulated sectional contacts,
which are hereinafter termed "motor contacts," since they form part of the motor
circuit; and C, C, also a set of contacts which are termed "switch contacts,"
their primary object being to provide a circuit through the magnets operating
the switches, as hereinafter described. Switches G, G1, G2, serve to connect the
motor contacts B, B with a feeder or distributing main H, forming the positive
branch of the generator circuit. A blow-out magnet coil 6 is provided for each
of the line switches to extinguish arcs forming at the switch contacts. Magnet
coils, of relatively high resistance are connected between the switch con-
tacts C, C and the rail A, which is assumed to be grounded. These coils serve to
pick up the switches and receive in the arrangement herein shown, the full line
potential. The shoe or collector F is connected to the positive terminal of the
motors M M upon the car, whose wheels are represented at D¹, D¹. In Fig. 1 the
negative terminal of the motors is grounded through the wheels. The shoe is
shown in Fig. 1 as long enough to somewhat more than bridge three of the road
contacts. A storage battery E is shown connected between the shoe F and the
car wheels D in a manner now well known in the art, and may be used to pick up
one or more of the switches if the line current fails to be operative for this purpose.

page_text: The shoe F is joined at f, or given flexibility by any equivalent means at this
point, so that its two parts may have sufficient independence off movement to
ensure making good contact with three studs at the same time, notwithstanding
minor changes in the level of the studs or contacts. Blow-out magnet coils b
are also inserted in the connections between the switch contacts C and magnets g
to extinguish arcs at the street surface should contact be ruptured at this point
while the full notential is operating.
Thus far the system illustrated in Fig. 1 of the drawings has been described,
since the remaining diagrams differ only in showing certain additions which may
be made when desired. Still referring to Fig. 1, with the parts shown in the
position illustrated, the switch G₁ is closed and current passes from either or both
of the motor contacts B, B upon which the shoe F rests, to the motors and thence
to the ground. A shunt circuit is also formed through switch contact C and the
high potential coil g' corresponding to switch G. Both the motor contacts B, B
are connected to the feeder through the same switch G¹. If now the car advances
in the direction of the arrow, the collector will next touch a new switch contact C
closing the switch G and connecting with the feeder the pair of motor con-
tacts B, B, on either side of the switch contacts. One of these motor contacts is
already connected through the switch G¹; by connecting it through the switch G
however the shoe F may leave the switch contact C which it engages in the diagram
allowing the switch G¹ to open without changing at all the electrical condition
of the motor contact B located between the two switch contacts just mentioned.
In this way, as will be apparent, each of the motor contacts is connected first to the
feeder through one switch, then through the next switch in advance; then the
first switch opens and finally the second switch opens, the net result however being
that each switch contact is in this peculiar way maintained in connection with the
feeder for a longer interval of time than that during which the switches,
individually considered, are held closed.
In Fig. 2 it is easy to trace on the diagram all the parts already described in
connection with Fig. 1, and their operation is the same. In the system shown in
this figure however the magnets operating the switches G, G, G³, are provided
not only with the shunt pick-up coils 9, but also with the series hold-up
coils go, go, forming part of the circuit between the feeder and the different motor
contacts B, B; so that the armature of the magnet is attracted not only by the
shunt coils, but by the series coils, and the switches would be held closed even
should the shoe F for one reason or another fail to make the proper contact with
the switch contacts.
Fig. 3 illustrates an alternative arrangement of the shoe F which may be
employed. Here there are two shoes side by side and overlapping for a portion
of their length. The shoes are capable of independent motion and are cross-
connected by a cable L or other suitable means so that the two shoes from an
electrical standpoint are the equivalent of a single shoe.
In Fig. 4 a series hold-up coil has been added to the switch operating magnets,
but in this case the hold-up coils g³, g³, are connected between an additional row
of sectional contacts C¹, C¹, 0, and the rail, so that the magnet coil is connected
in series between the negative terminal of the motors M, M and the ground. In
this case a second collector or shoe F¹ is provided which rides upon the con-
tacts C, C and the negative terminal of the motor M is connected to the shoe F¹
instead of being grounded directly, as in the systems of Figs. 1 and 2.
sectional conductors are illustrated as arranged outside of the rail to reduce the
danger of leakage current from the positive contacts B, B, holding the switches
closed through the low resistance coils g³.
The
Haivng now particularly described and ascertained the nature of this 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. In a surface contact railway system, a single row of section contacts, some of

page_text: which are directly connected to the feeder by the closing of suitable electro-
magnetic switches, while others are connected to ground through high resistance
magnets actuating the switches, the high resistance coils of these magnets forming
a shunt to the motor circuit, and permanent electrical connections connecting each
of the motor contacts with more than one of the switches and each of the switches
likewise with a plurality of motor contacts, as set forth.
2. In an electric railway system, the combination of a feeder, sectional motor
contacts and switch contacts arranged alternately in a single row, electro-magnetic
switches for connecting the sectional motor contacts with the feeder in sequence
and permanent electrical connections between the contacts and switches such that
current may flow from a given contact to the motor, first through one of the line
switches and then through a second switch, said switches operating successively;
whereby each motor contact is connected to the feeder for a longer interval of
time than that during which any line switcu individually considered is held closed.
3. The combination in an electric railway, of sectional motor contacts and switch
contacts arranged alternately in a single row, grounded high potential magnets
connected to the switch contacts, switches, permanent electrical connections for
connecting the motor contacts in pairs to the source of supply through the switches,
and a collector for maintaining during normal operation a circuit through the
magnets in shunt to the motor circuit.
4. In an electric railway, the combination of switch contacts C alternating with
motor contacts B in a single row, grounded high potential magnets connected to
the switch contacts, switches picked by the magnets, permanent electrical connec-
tions from each switch to a pair of the motor contacts and from each motor con-
tact to a pair of the switches, and a collector adapted to bridge three of the
sectional contacts, as set forth.
5. In an electric railway, the combination of a feeder, sectional motor and
switch contacts, electro-magnetically operated switches connecting the motor
tacts with the feeder, permanent electrical connections between the motor contacts
and switches, whereby each switch makes connection with a pair of motor contacts
and each motor contact may also be connected through a pair of switches, a
collector completing the motor circuit from the motor contacts, magnets operating
the switches having a shunt coil forming part of a circuit around the motor, and a
series coil in circuit with the motor, for the purposes set forth.
Dated the 7th dow of Santamban
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