Safety Appliance for Electrical Circuits.
Year: 1895

page_text: Date of Application, 7th May, 1895-Accepted, 15th June, 1895
German Empire, Electrical Engineers.]
Safety Appliance for Electrical Circuits.
We, SIEMENS BROTHERS & Co. LIMITED, of 12, Queen Anne's Gate,
Westminster, in the County of Middlesex, Electrical Engineers, do hereby
deolare the nature of this invention and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement.—
The Specification to the German Patent No. 67092 describes an arrangement
whereby an electrical conductor is automatically separated from the source of
electricity when it is broken by any means Such an arrangement is particularly
necessary for the security of the working of electrical railways because owing to
the inherent conditions of working in such cases, the conductors are firstly more
subject to fracture than elsewhere, and secondly, such fractures are the cause of
considerable damage and even danger.
The above mentioned arrangement however is subject to a series of defects,
which it is the object of the present invention to obviate.
As the cutting out device is worked on open circuit, it is not only subject to all
the uncertainty of action to which all such apparatus as are worked on open
circuit and are only put in action on exceptional occasions are liable, but the
reliableness of its action is also dependent upon the fracture taking place under
definite conditions
The fracture must only occur in the main conductor and not simultaneously in
the auxiliary conductor connected in parallel therewith, and it must occur at a
point of the main conductor through which current is passing. These conditions
render the application of the said device impracticable in a large number of
cases.
According to the present invention, there is provided in addition to the main
conductor a thin auxiliary or subsidiary conductor, which commences at the
distant end E of the circuit, as shewn on the accompanying diagrammatic drawing,
and terminates at the point A where the electrical energy is supplied, either from a
dynamo, as shewn in the drawing, or from another branch of the electrical
railway.
As will be seen, this auxiliary conductor forins & closed loop with the main
conductor, which, when carriages are running on the line, is connected in series
with the main couductor which it is to protect. In this auxiliary conductor there
19 introduced at the source of current supply A a closed circuit-electromagnetic
cut-out device of any suitable known construction which cuts off the circuit from
the source of supply simultaneously with the fracture of the conductor, that is to
say, when the auxiliary conductor receives no current or the said device may be
connected in any suitable known manner to a signal apparatus which is made to
indicate the fact of the said rupture having occurred either by an audible or a
visible signal. Or the automatic cut-out device may be made to operate in
combination with a signalling device.
'

page_text: 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 :-
A safety appliance for electrical circuits where that end of a conductor
supplying electrical energy, which is farthest away from the source of current
supply is connected in series with the opposite pole of such source of supply by
means of an auxiliary conductor in which is introduced a closed circuit-electro-
magnetic cut-out device so arranged as to automatically cut off the supply conductor
from the source of current when the auxiliary conductor ceases to receive current,
substantially as described.
Dated this 7th day of Mov 1905
ABEL & IMRAY,
Agents for the Applicants.