CIRCUIT BREAKER WITH ADJUSTABLE MAGNETIC TRIP UNIT

摘要

52,893 A circuit breaker structure having an adjustable magnetic trip unit characterized by an insulating housing containing a circuit breaker mechanism having separable contacts and containing a trip unit comprising a magnetic device responsive to overload current conditions for separating the contacts, the magnetic device having an armature and a calibrating screw for calibrating an air gap between the armature and an associated magnet, the trip unit also including a cam for varying the tension of the spring and the cam having spaced indexing indentations and an associated ball in the frame for rolling engagement with the cam surface and for seating in any indentation to provide positive settings of the spring tension.