Allen-bradley Company, LLC

Siemens Energy & Automation, Inc.

Gustave E Heberlein, Jr

Terrance D Nelson

John M Brown, Jr

David P McClellan

An apparatus for protecting the fault current intolerant elements of a motor starter circuit or the like is comprised of a protective shunt which bypasses the fault current intolerant elements in response to the detection of high fault currents. The protective shunt is formed of a 'U' shaped conductor which flexes in response to the magnetic field created by the flow of the high fault currents through the 'U' shaped conductor. Electrical contacts place on one leg of the 'U' shaped conductor and on a stationary conductor form a shunting switch which conducts high fault currents around the starter circuitry. In a second embodiment, the stationary conductor is replaced with a flexible conductor which carries an armature. The magnetic armature is attracted by a focussed magnetic field from a magnetic yoke positioned around one leg of the 'U' shaped conductor.

Method and device for protecting starters from fault currents

A current limiting circuit breaker is provided which has a stationary contact assembly and a movable contact bridge. A contact carrier is connected to the contact bridge and biases the contact bridge toward the closed position. The downward biasing force on the contact bridge is mechanically reduced in response to a preselected amount of opening movement of the contact bridge.

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Delafield, WI, United States of America

Gustave E Heberlein, Jr