Square D Company

Paul J Rustebakke

Gary W Scott

Clark L Oster

Neil R Palmer

Daniel R Schiefen

The present invention provides a compact transformer with a magnetic core having at least two leg members and two side members. Each leg member has two ends and a peripheral surface therebetween. Each side member has a generally planar body with at least two notches corresponding in cross-sectional shape and size to the end of each leg member. The sides of each notch surround and abut a majority of the peripheral surface near each leg member end. The leg member end is secured to each notch. A magnetically coupled primary and secondary winding is arranged around each leg member. The transformer is particularly useful in sending current signals to an electronic trip unit of a circuit interrupter. The invention also includes a method of assembling a transformer which includes the steps of providing a magnetic core having at least two leg members with two ends and a peripheral surface therebetween and providing two side members of approximately the same shape having a generally planar body with at least two notches corresponding in cross-sectional shape and size to the end of each leg member. The method includes pressing and securing the peripheral surface near the end of each leg member against the sides of each notch so that the sides of each notch surround and abut a majority of the peripheral surface near each leg member end.

Compact transformer and method of assembling same

A fastenerless electromagnetic trip assembly employs minimal parts for effecting the release of a set of circuit breaker contacts. The parts include an armature, an armature bias spring, a yoke and a trip bar, all of which may be retractably supported in associated compartments within the circuit breaker housing. The yoke provides an electromagnetic field in response to electric current flowing in the circuit breaker. A spring biases the armature until the electromagnetic field reaches a predetermined strength, at which point the bias is overcome, and the armature strikes the trip bar and is drawn toward the yoke, thereby causing the trip member to actuate the release of the circuit breaker contacts.

Non-jamming magnetic trip structure

A circuit breaker for breaking current conduction between line and load connectors in response to tripping of a bimetallic thermal element as a result of an over-current condition is disclosed. According to the invention, a trip crossbar is permitted to translate as well as rotate to relieve stress on the thermal element.

Growing community of inventors

Cedar Rapids, IA, United States of America

Paul J Rustebakke