US 7,397,333 B2 · Trip unit having bimetal element located outside the yoke

Abstract

A trip unit in a miniature circuit breaker includes a magnetic yoke and a bimetal mounted on the outside of the yoke. The bimetal is welded at one end to a load terminal that leads to a terminal connector and at the other end to a pigtail. The pigtail, instead of the bimetal, passes through the yoke for connection to the blade of the circuit breaker. To induce a higher magnetic field for faster tripping, a second pigtail may be passed through the yoke in which one end of the second pigtail is connected to the load terminal near the terminal connector and the other end is connected to the bimetal near the load terminal connection point. The load terminal may include at least two parts, one part including the adjustment screw and the other part including the terminal screw. These parts may be separated by air or an insulator.

Claims21

Dependent claims

A trip unit for use in a circuit breaker, comprising:

a magnetic yoke having a shaped portion defining a channel, said shaped portion having an inner surface facing an armature of said trip unit and having an exterior surface opposite said inner surface and facing away from said armature of said trip unit;
a pigtail conductor, a portion of which is received in said channel, attached to a conductive blade of said circuit breaker;
a bimetal mounted to at least a portion of said exterior surface such that said bimetal extends along the length of said exterior surface, said bimetal having a length that is longer than said shaped portion;
and
a load terminal attached to one end of said bimetal, said bimetal being attached to said pigtail conductor.

2 more elements

A trip unit for a miniature circuit breaker, comprising:

a magnetic yoke having an inner surface facing an armature of said trip unit and having an exterior surface opposite said inner surface and facing away from said armature;
a conductive blade coupled to movable contacts in said circuit breaker;
a load terminal having an end part that includes a terminal connector;
a bimetal attached at one end to said load terminal of said circuit breaker and at another end to at least a portion of said exterior surface such that said bimetal extends along the length of said exterior surface, said bimetal having a length that is longer than said magnetic yoke;
and
a flexible conductor attached to said conductive blade and to said bimetal, a portion of said flexible conductor passing along said inner surface opposite said bimetal.

3 more elements

Dependencies are inferred from the claim text.

Trip unit having bimetal element located outside the yoke

Life of this patent

Trip unit having bimetal element located outside the yoke

Life of this patent

Abstract

Claims21