Abstract:

When the small low voltage DC circuit breaker breaks the critical load current,it is difficult to break the circuit because of the weak effect of magnetic blowing and gas blowing on the arc.A permanent magnet is added at the corner of the static contact assembly.Through analyzing the quenching mechanism of miniature low voltage DC circuit breaker,the magnetic field simulation and test verification of miniature low voltage DC circuit breaker before and after adding permanent magnet are carried out.The results show that the addition of permanent magnets can enhance the magnetic field intensity at the position of the arc,increase the Lorentz force of the arc,and help the miniature low voltage DC circuit breaker to improve the ability of breaking the critical load current.

Key words: miniature low voltage DC circuit breaker, permanent magnet, magnetic field strength, critical load current, test standard