Relay Apparatus for Closing a Subsidiary Circuit of an Electrical Installation, when a Current in the Main Circuit has a Certain Strength or Voltage.
Year: 1899

page_text: Date of Application, 27th May, 1899-Accepted, 8th July, 1899
COMPLETE SPECIFICATION.
Relay Apparatus for Closing a Subsidiary Circuit of an Electrical
Installation, when a Current in the Main Circuit has a Certain
Strength or Voltage.
We, SIEMENS BROTHERS & Co., LIMITED, of 12, Queen Anne's Gate, West-
minster, S.W., in the County of London, Electrical Engineers, do hereby declare
the nature of this invention (as communicated to us from abroad by Siemens &
Halske Aktien Gesellschaft, of Markgrafen Strasse 94, Berlin, S.W., Germany,
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 an appliance whereby, when a certain strength or
voltage of current occurs in an electric circuit, a second circuit is closed in which
is included an optical or audible signal, a regulating device, or the like.
For this purpose a contact device is combined with any kind of electrical
measuring apparatus in such manner that by the depression of the pointer of the
measuring apparatus when this is in the position corresponding to a certain
strength or voltage of the current, a contact device will be actuated, and thereby
a circuit be closed.
This arrangement differs from known arrangements for the same purpose wherein
the pointer itself makes the electrical contact when a current of definite strength
or voltage passes through the measuring coil.
We will describe the invention with reference to the accompanying diagram-
matic drawing shewing the general arrangement.
Fig. 1 shews a plan, and Fig. 2 a sectional side view. A is an electrical
measuring mstrument of any suitable known construction for measuring the
strength of a current or its voltage. a and are the terminal clamps for the
current to be observed. B is the pointer of the measuring instrument, C is an
ordinary contact device.
In the arrangement shewn it consists of a thin contact spring k with platinum
contact, mounted in an insulated manner upon a support which constitutes the
second contact.
Both contacts and are included in a circuit which, as above stated includes
a signalling device D, or the like.
The contact device Ċ is situated at the position which the pointer assumes with
a certain strength of current, the pointer being then over the contact spring k.
lf, when the pointer is in this position, pressure be exerted on the pointer the
contact spring will be actuated so as to close the said circuit.
For effecting the pressure on the pointer B a great variety of devices can be
employed, the pressure being effected either mechanically or electrically.
In the drawing the latter arrangement is shown the action being controlled by
clockwork. E is an electromagnet or a relay, which may be polarised and which
is included in a circuit containing a battery and a contact wheel G actuated by
a clockwork F. The armature H of the relay has an extension which projects
over the contact device C in such manner that the pointer B can move freely
between the two. When the contact wheel G closes the circuit of the relay E,

page_text: the armature H thereof will be attracted and its extension will consequently press
the pointer down upon the spring k, if the former be in the correct position con-
sequent upon a current of the desired strength passing through the instrument,
and on making contact with the signalling circuit will be closed.
If it be required not only to observe a definite strength of current, but also
the increase or decrease of a current above or below a certain mean, it will only
be necessary to provide the contact device with a stop against which the pointer
will bear.
By the extension of the armature and the provision of several contacts, the
apparatus can also be arranged to act as a multiple relay.
Having now particularly described and ascertained the nature of this invention
and in what manner the same is to be performed, we declare that what we claim
is:-
Relay apparatus consisting of the combination of an electrical measuring
instrument with a contact appliance in such manner that with a certain strength
of current or voltage in the circuit the pointer of the instrument will be situated
over a contact device which is then actuated by the depression of the pointer so
as to close a secondary circuit, substantially as described.
Dated this 27th day of May 1899.
ABEL & IMRAY,
Agents for the Applicants.