US 5,296,827 A · Circuit breaker with magnetic shield

Abstract

A pivoting lower contact arm arrangement and a circuit breaker including the arrangement. The pivoting lower contact arm arrangement includes a pivoting lower contact arm and a biasing arrangement. The biasing arrangement maintains the contact arm in an operating position with a first force, and biases the arm from a blown-open position toward the operating position with a second force. The first force is greater than the second force to provide increased separating speed when the pivoting lower contact arm blows apart from a pivoting upper contact arm of the circuit breaker and moves from its operating position. The biasing arrangement also variously provides magnetic shielding and coupling between the pivoting lower contact arm and other current carrying components of the circuit breaker. The magnetic shielding enhances the blow-apart forces between the pivoting upper contact arm and the pivoting lower contact arm.

Claims17

Dependent claims

A circuit breaker contact arm support assembly comprising:

an electrically conductive contact support having:
a terminal portion;
an end portion;
and
first and second generally parallel, spaced-apart side members which extend between the terminal and end portions, where the members conduct current in parallel and in the same direction between the terminal and end portions;
a circuit breaker contact arm pivotally coupled to the conductive contact support end portion in an electrically conductive manner, so as to pivot between a first position and a second position between and generally coplanar with the generally parallel side members;
and
a magnetic shield interposed between the arm and the conductive support side members;
such that when the arm is in the second position and current is being conducted through the contact support and arm, the generally coplanar orientation of the contact support side members and contact arm in combination with the shield interposition therebetween reduces magnitude of magnetic forces which cause movement of the arm from the second position to the first position.

6 more elements

A circuit breaker comprising:

a base;
an operating mechanism fastened to the base;
a first contact arm coupled to the operating mechanism such that the contact arm is movable between an open position and a closed position;
a conductive contact support fastened to the base having:
a terminal portion;
an end portion;
and
first and second generally parallel, spaced-apart side members which extend between the terminal and end portions, where the members conduct current in parallel and in the same direction between the terminal and end portions;
a second contact arm pivotally coupled to the conductive contact support end portion in an electrically conductive manner, so as to pivot between a first position and a second position generally coplanar with the generally parallel side members, such that electrical current may flow in the support and the arms when the first contact arm is in the closed position and the second contact arm is in the first position;
and
a magnetic shield interposed between the second contact arm and the conductive support side members;
such that when the second arm is in the second position and current is being conducted through the contact support and second arm, the generally coplanar orientation of the contact support side members and second arm in combination with the shield interposition therebetween reduces magnitude of magnetic forces which cause movement of the second arm from the second position to the first position.

9 more elements

Dependencies are inferred from the claim text.

Circuit breaker with magnetic shield

Life of this patent

Circuit breaker with magnetic shield

Life of this patent

Abstract

Claims17