Improvements in Electric Cut-outs or Circuit Breakers.
Year: 1888

page_text: Date of Application, 5th Dec., 1888
Complete Specification Left, 5th Sept., 1889-Accepted, 12th Oct., 1889
PROVISIONAL SPECIFICATION.
Improvements in Electric Cut-outs or Circuit Breakers.
We, THOMAS PARKER, of the firm of Elwell-Parker Limited, Electrical Engineer,
and EDMUND SCOTT GUSTAVE REES, Electrical Engineer, both of Commercial Road
Wolverhampton in the County of Stafford, do hereby declare the nature of this
invention to be as follows:
This Invention relates to apparatus for automatically opening or breaking an
electrical circuit when the current in the circuit exceeds a pre-determined amount.
An apparatus constructed according to these Improvements consists of an electro-
magnet, an armature, a switch, and a trigger which is operated by the armature to
release the switch. The coil of the electro-magnet may form part of the main circuit
or it may be included in the shunt across that part of the circuit in which the e.m.f.
is generated. The armature is held away from the electro-magnet by a weight or
spring sufficient to prevent the attraction of the armature into contact with or
proximity to the poles of the magnet until the current reaches a certain amount. The
armature is provided with a projecting part or is otherwise constructed so that some
portion of it comes into contact with and releases the trigger when the armature is
attracted. The trigger is constructed and arranged to hold the switch in a position
closing the circuit until the trigger is released whereupon the switch is pulled open by
a spring. The switch is closed by hand.
Dated this 3rd day of December AD 1888
WILLIAM E. HEYS,
Agent for the Applicants.
COMPLETE SPECIFICATION.
Improvements in Electric Cut-outs or Circuit Breakers.
We, THOMAS PARKER of the firm of Elwell-Parker Limited, Electrical Engineer,
and EDMUND SCOTT GUSTAVE REES, Electrical Engineer, both of Commercial Road
Wolverhampton in the County of Stafford, do hereby declare 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:-
This Invention relates to apparatus for automatically opening or breaking an
electrical circuit when the density or the pressure of the current exceeds a predetermined
amount.
An apparatus constructed according to these Improvements consists of an electro
magnet; an armature; a switch; and a catch or trigger which is operated by the
armature to release or open the switch. The coil or coils of the electro-magnet may
be included in the main circuit or in a shunt across that portion of the circuit in which
the e.m.f. is generated. The armature is held away from the electro magnet by means
of a weight or spring sufficient to prevent the attraction of the armature into contact
with or proximity to the poles of the electro-magnet until the e.m.f. or the density of
the current exceeds a certain amount. The armature is provided with a projecting
part or is otherwise so constructed that some portion of it comes into contact with and
releases the trigger when the armature is attracted into close proximity to the poles
of the magnet. The trigger is constructed and arranged to hold the switch in a
position closing the circuit until the trigger is released, whereupon the switch is
pulled open by a spring or weight. The apparatus is so constructed and arranged
that the switch is not operated by the motion of the armature until almost in contact
with the poles of the magnet when, owing to its momentum. and the increased magnetic
field, it will have gained sufficient power to effectively release the trigger which then
Prine 677

page_text: allows the switch to fly off and break the circuit. The switch is closed by hand but
if the current or the e.n.f. is still too great, it will not remain closed because the
automatic action of the apparatus will instantly re-open it, and the circuit cannot
therefore be closed until the e.inf. and current are at or below the pre-determined
amounts.
In the accompanying sheets of drawings which illustrate in what manner our
Improvements may be carried into practical effect, Fig. I represents the apparatus in
the form in which we prefer to construct it. Fig. 2 represents a modified form of the
apparatus as constructed for. comparatively small currents. Fig. 3 represents (with
the apparatus) a diagram of the circuits and connections as arranged if it is desired
to open the main circuit when the density of the current exceeds a certain pre-
determined amount, and Fig. 4 is a similar diagram shewing the arrangements and
connections when it is desired to open the main circuit upon the pressure exceeding
the pre-determined limit.
In each of the Figures Ais the electro-magnet; B.is, the armature; (is the switch;
D is the trigger or catch; E is a spring tending to force the switch open; F is a stop
limiting the notion of the switch; G isa.handle by means of which the switch may
be closed; H is a spring tending to keep the switch closed; I is an adjusting and
regulating screw; Lis the working circuit; M is the dynamo ; S is a shunt circuit;
(Fig.4.) T and T are the terminals of the main circuit, and T3 and T are the
terminals of the shunt.circuit. (Fig. 4).
The operation of the apparatus will be readily understood from the description
already given and by reference to the drawings. The armature B is at the normal
strength of the current held by gravity or by a spring in the position indicated in the
various Figures and the switch is closed. So soon as the pressure or the density of
the current (as the case may be) exceeds a certain pre-determined amount for which
the apparatus is adjusted by the screw R, the armature is attracted with an accelerating
velocity towards the,magnet and it is not until it is near the poles of the magnet,
when it has acquired its maximum force that its projection N comes into contact with
the catch or trigger D with a smart blow, thus rendering the operation of the switch
absolutely certain. The circuit having thus been broken, the switch is held open by
the spring E but it may be closed by hand by means of the handle G, which brings the
catch or trigger into engagement with the stud or projection 'K.
Having thus particularly described and ascertained the nature of our said
Invention and in what manner the same is to be performed, we declare that what
we claim is :-
An electric cut-out or circuit breaker constructed arranged and operating
substantially as hereinbefore described with reference to the accompanying drawings.
Dated this 3rd day of September A D 1880
WILLIAM E. HEYS,
Agent for the Applicants.