Thermally independent overcurrent tripping device

摘要

Exemplary embodiments are directed to an electrical overcurrent tripping device for a circuit breaker. The tripping device includes an actuating member which in case of an overcurrent is driven to interact directly or indirectly with a movable contact piece of the circuit breaker to open a contact point in the circuit breaker if the overcurrent is exceeding a preset tripping threshold for a predetermined tripping delay time. The actuating member is coupled to a magnetic circuit such that the driving force acting on the actuating member is created by the magnetic field of the magnetic circuit, said magnetic field being induced by the overcurrent. The actuating member is coupled to an electromagnetic damping arrangement to set the tripping delay time, and is connected to a coupling spring configured to adjust the overcurrent tripping threshold.