Square D Company

Other

James A Tharp

Clark L Oster

An electric circuit breaker including a U-shaped bimetal operably associated with a trip crossbar to effect rotation of the crossbar and subsequent opening of breaker contacts in response to heating of the bimetal to a predetermined temperature by the passage of an electrical current of a selected magnitude therethrough. The bimetal provides self-contained adjustment through the use of a calibration screw threaded into the lower leg of the bimetal which exerts force through an insulating member to the upper leg of the bimetal permitting ready calibration of the bimetal according to ampere rating of the particular circuit breaker.

Circuit breaker with self contained adjustable bimetal

A floor panel designed particularly for computer room raised access floors, the floor panel including a pan containing a relatively thick chip board core material, a PVC impact molding fitted between the edges of the chip board core material and the inner side of the pan, the PVC impact molding resting upon the upper edges thereof, the PVC impact molding framing a top galvanized steel sheet on top of which a carpet is fitted.

Raised access floor system

A current limiting circuit breaker having for each pole, a pair of main contacts separable upon operation of a thermally and electromagnetically operable tripping device and a pair of auxiliary contacts for current limiting in series with the main contacts and in parallel with a transformable resistor having a positive temperature coefficient of resistance. The auxiliary contacts are separable when an electromagnet is energized by a fault current which simultaneously energizes a field magnet to produce a transverse magnetic field across the auxiliary contacts and the arc formed between them when separating. This simultaneous action of electromagnet and field magnet coacting for rapid contact separation and lengthening of the arc upon flow of a fault current serves to increase arc voltage almost instantaneously to that of the source, about which time the fault current is totally shunted into the resistor. An armature and armature pin are mounted for reciprocal movement when the electromagnet is energized. The armature pin is operatively connected to the auxiliary contact blades which are mounted for pivotal movement from a contact closed to a contact open position when the armature and armature pin are attracted by the electromagnet. A compression coil spring encircles the armature pin to bias the auxiliary contact blades toward a normally contact closed position.

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Cedar Rapids, IA, United States of America

James A Tharp