Allen-bradley Company, LLC

Terrance D Nelson

Gustave E Heberlein, Jr

Donald W Kuntzsch

Bruce G Klippel

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

Both solid state static control devices and electromagnetically operated contactors are employed in an a-c motor starter. The solid state control devices are operated by an acceleration control circuit to accelerate the motor during start-up. When synchronous speed is achieved, a run contactor is energized and its contacts are closed to conduct motor current. Under steady state conditions, therefore, the solid state control devices are bypassed.

Hybrid motor starter

A switch cartridge wedgingly retains an electrical terminal structure having a terminal housing with a hollow interior which receives a threaded fastener and a terminal. The threaded fastener carries a pressure plate which is restrained against rotation and translated toward the terminal upon tightening of the fastener within the terminal housing. A wire is inserted into the terminal housing and firmly held between the pressure plate and the terminal by tightening the fastener thereby making a direct wire to terminal contact.

Growing community of inventors

Cudahy, WI, United States of America

Terrance D Nelson