Thermally independent overcurrent tripping device

A circuit breaker with an electrical overcurrent tripping device comprising:

• at least one contact point with a fixed contact piece and a movable contact piece,
• wherein said tripping device includes an actuating member which in case of an overcurrent is driven to interact directly or indirectly with the movable contact piece to open the contact point if said overcurrent exceeds a preset tripping threshold for a predetermined tripping delay time,
• wherein said 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 overcurrent, said actuating member is coupled to an electromagnetic damping arrangement to set the tripping delay time, and said actuating member is connected to a coupling spring configured to adjust the overcurrent tripping threshold,
• wherein said actuating member is an electromagnetically damped rotor in a magnetic circuit where the driving magnetic field is created by the load current,
• wherein the magnetic circuit includes a tubular stator as part of the magnetic core of the magnetic circuit with at least one winding of a conductor embracing the magnetic core and carrying at least partly the load current, and
• wherein the stator at least partially embraces the rotor and the rotor is rotatably mounted within the stator.

An electrical overcurrent tripping device for a circuit breaker, comprising:

• a magnetic circuit for generating a magnetic field induced by an overcurrent;
• and
• an actuating member driven by the magnetic field of the magnetic circuit, wherein said actuating member interacts with a movable contact piece of the circuit breaker to open a contact point in the circuit breaker if the overcurrent exceeds a preset tripping threshold for a predetermined tripping delay time;
• an electromagnetic damping arrangement coupled to the actuating member to set the tripping delay time;
• and
• a coupling spring connected to said actuating member for adjusting the overcurrent tripping threshold,
• wherein said actuating member is an electromagnetically damped tubular rotor having a permanent magnet in a magnetic circuit where the driving magnetic field is created by the load current,
• wherein said magnetic circuit includes a tubular stator as part of the magnetic core of the magnetic circuit with at least one winding of a conductor embracing the magnetic core and carrying at least partly the load current, and
• wherein said stator at least partially embraces the rotor and the rotor is rotatably mounted within the stator.