Switch and Contact Apparatus for the Cars of Electrical Railways and Tramways.
Year: 1898

page_text: Date of Application, 7th July, 1898-Accepted, 17th Sept., 1898
COMPLETE SPECIFICATION.
Switch and Contact Apparatus for the Cars of Electrical Railways and
Tramways.
We, SIEMENS BROTHERS & Co. LIMITED, of 12, Queen Anne's Gate, West-
minster, S.W., Electrical Engineers, do hereby declare the nature of this invention
(as communicated to us from abroad by Siemens & Halske Aktien-Gesellschaft,
Markgrafen Strasse 94, Berlin, S.W., Electrical Engineers) 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 switch and contact apparatus for the cars of electrical
railways and tramways having a mixed supply, that is to say, in which the
electrical energy is supplied partly from overhead conductors and partly from
accumulator batteries on the cars. The present improvements have for their
object to effect a more reliable working with this combined system of propulsion.
In railways or tramways of this kind, the electrical energy supplied on those
parts of the line that have overhead conductors is employed partly for propelling
the cars and partly for charging the accumulator batteries, which latter afterwards
supply the necessary working current on the parts of the line having no overhead
conductor, both for propulsion and for lighting.
According to the present improvements, a more reliable working is effected
by so arranging the switch apparatus that the attendant is obliged, under all
circumstances, on leaving the part of the line with the overhead conductor, to
disconnect the current collecting appliance from the car circuit, in which current
under pressure exists. To effect this a current collector of known construction
may be employed, by means of which on passing on to an overhead conductor
a resistance, such as a supplemental glow-lamp, is included in the lamp circuit
in order to prevent the burning out of the other lamps in consequence of the
increased pressure supplied from the overhead conductor. Such an arrangement
is described for instance in the Elektrotechnischer Auzeiger No. 28 of 4th
April 1897.
With that arrangement the current collector is disconnected from the electric
circuit when in the turned-down position, while when turned into the upright
position it is subject to electrical pressure.
We will describe our improved arrangement with reference to the accompanying
diagrammatic drawing, which shews in Fig. 1 the new switch apparatus with the
current collector in the turned-up position, while Figure 2 shews the same with
the collector turned down.
The contact apparatus at A consists of the contact pieces cc fixed in an insulated
manner to the current collector, and the contact piece d fixed in conducting con-
nection with the latter.
This contact piece has at its middle an inward bulge e or an insulating plate so
that when the current collector b is vertical the electrical conductor y connected

page_text: to the spring is put out of connection with the current collector, while, when in
an inclined position, in which the collector bis in contact with the overhead con-
ductor indicated at a Fig. 1, the electrical connection with g is established. The
conductor g, as also the conductor which is directly connected to the current
collector b, both lead to the commutator switch B.
From the contact spring f is also branched the conductor i leading to the lamp
resistances w.
The conductors lead from the contacts k k to the lamps and to the + pole
of the accumulators.
The commutator switch B, whose combination with controller switch S con-
stitutes the principal feature of the invention, has four contacts which are so
arranged that the connection of 1 with 2 and 3 with 4, either separately or together,
can be effected, or 2 can be connected with 3. A connection of 1 with 4 is pre-
vented by the mode of construction of the switch; for instance, if the distances
between 1 and 2, 2 and 3, 3 and 4, are equal, while that between 1 and 4 is
different, a horse shoe switch plug being used; or two horse shoe plugs may be
connected rigidly together as at Fig. 3, provided with a pin p so arranged,
the plugs can only be inserted in the contacts in the position in which p can fit
into a corresponding hole.
that
At Fig. 3 are shewn the three possible positions of the switch plugs. I shews
the position for running with overhead supply, and for charging the accumulators;
II for running with overhead supply without charging the accumulators,
III for running with accumulators.
Holes oo in the switchboard may serve as supports for the ends of the horse-
shoe plugs that are not in use for contacts.
From the contact 2 the conductor m leads to the controller switch S and from
contact 3 the conductor n leads to the + pole P of the accumulators.
There would of course be no difficulty in arranging a lever switch to fulfil the
above described conditions.
The commutator switch can also serve as emergency cut-out, so that the greatest
possible security in working is afforded by this construction:
The commutator switch B can of course be constructed in any desired manner,
'so long as the conductors g h m and n are thereby connected in the above described
manner, and at the same time, so that the conductor m can only be connected with
either nor h respectively but never to both at the same time.
The apparatus operates as follows.
.
On the sections with overhead supply the spring f is connected to the current
collector 6 by means of the contact piece d, so that the current passes through
conductors hand g respectively to the contacts 1 and 4 of the commutator B.
When the car leaves the overhead supply section, the current collector is made
to assume the vertical position by its usual actuating device so that the spring f
is then out of contact, and the current collector is consequently disconnected from
the lamps and the accumulator batteries.
In order now to continue running with the accumulator batteries, the controller
switch S must be directly connected with the battery. To effect this the attendant
is however forced to break the connection 1-2 and to establish the connec-
tion 2-3.
By this action the current collector is also disconnected from the controller
switch; and consequently from the electrical circuit.
The fact that the current collector is cut out in the vertical position, constitutes
an essential advantage of the above described arrangement over known arrange-
ments, in which the current collector is only cut-out when it is in the turned-down
position. As the turning down is frequently omitted through forgetfulness, such
arrangements are not excluded from danger. The current collector of course
remains cut out when in the turned-down position, while running with the
accumulator current, as before the connection of the accumulators with the lamp
circuit, the latter will be disconnected from the current collector.

page_text: Telephone or telegraph wires that may drop on to the roof of the car are con-
sequently not liable to cause danger, such as would occur if the current collector
were connected with the electrical circuit.
The connection of the lamp circuit with the several positions of the current
collector is clearly shewn from the diagram.
It will be seen that when the current collector is vertical the lamp circuit
is broken at kk', but when the collector is turned down in one direction or the
other, the one or other insulated contact piece of the collector effects the closing
of such circuit. By this means the new advantage is gained that if on passing
from the overhead supply to the accumulator supply, the attendant forgets to turn
down the collector, he will be reminded of this by the extinguishing of the lamps,
as these receive no current from the accumulator while the circuit ll is broken.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, we declare that what we
claim is:-
1. In switch apparatus for the cars of electrical railways and tramways having
a mixed supply, providing the current collector with a contact piece such as ./
in conducting connection therewith and so arranged in combination with a fixed
contact such as f connected with conductors leading to the accumulators and the
lamp circuits, that when the collector is in the vertical or in the horizontal position
it is disconnected from the said contact, while when it is in the inclined position
the said contact piece establishes the connection between it and the accumulator
and lamp circuits, substantially as described.
2. In combination with the contact device referred to in the first claim, a switch
apparatus whereby the attendant is obliged to effect the change from overhead
supply to accumulator supply when leaving an overhead conductor section of the
line, such apparatus having four contacts leading respectively (1) directly to the
current collector, (2) to the controlling switch, (3) to the accumulators and (4) to
the above mentioned contact device, and these contacts being so arranged that the
controller switch contact (2) can only be connected either with contact (3) to the
exclusion of the other connections, or with contact (1) with the object of entirely
cutting out the current collector when running under accumulator supply, sub-
stantially as described.