US 4,698,606 AGranted

Circuit breaker with adjustable thermal trip unit

AssigneeWestinghouse Electric Corp.

InventorsStephen A. Mrenna, Michael J. Whipple

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Abstract

A circuit interrupter responsive to abnormal currents in conductors of an electrical distribution system characterized by a circuit breaker mechanism for opening and closing separable contacts and which mechanism comprises a releasable member operable between latched and unlatched positions, trip means comprising a bimetal element and a trip bar movable to unlatch the circuit breaker mechanism and biased in the latched position, the trip bar having a surface facing and spaced from the bimetal element which surface is slanted at an oblique angle to the longitudinal axis of the trip bar, and manually adjustable knob connected to the trip bar for sliding the trip bar longitudinally to vary the space between the bimetal element and the trip bar surface in accordance with a desired thermal rating.

Claims9

Dependent claims

A multi-pole circuit breaker comprising:

a circuit breaker structure having a plurality of pole units;
each pole unit comprising a pair of separable contacts;
releasable means including a releasable arm to effect simultaneous opening of all of said pairs of contacts;
trip means for each of the pole units, each trip means having a bimetal element responsive to the occurrence of overload current conditions to effect release of the releasable means;
the trip means also comprising at least one integral a trip bar that is movable perpendicularly of the bimetal elements;
the trip bar including a ramp having a surface facing and spaced from each bimetal element which surface is inclined at an angle to the perpendicular axis of the trip bar;
the trip bar being rotated to a tripped position when at least one of the bimetal elements moves against a corresponding ramp surface;
and
adjusting means associated with the trip bar for adjustably moving the trip bar perpendicularly to a position corresponding to the desired thermal rating spacing, whereby the perpendicular position of the trip bar establishes the thermal rating spacing.

6 more elements

Dependencies are inferred from the claim text.