Solenoid plunger unit for use as overcurrent detection unit of protective motor switch, has trigger coil producing magnetic attraction force on plunger due to overcurrent, where air gap is independent of adjustable triggering ranges

摘要

The unit (1) has a trigger coil (2) producing a magnetic attraction force on a solenoid plunger (5) due to overcurrent. The force of the detection spring holds the solenoid plunger before triggering of the solenoid plunger in a position predetermined by a defined stopper (6). An air gap (10) remains constant and is independent of the adjustable triggering ranges. The detection spring changes the triggering ranges through adjustment of the spring. A magnet pot (4) is provided for aligned return flow of the magnetic field.