Small-current magnetic blast arc quenching device for DC (direct current) circuit breaker on basis of permanent magnetic circuit conversion method

Abstract

The invention discloses a small-current magnetic blast arc quenching device for a DC (direct current) circuit breaker on the basis of a permanent magnetic circuit conversion method, which is assembled on the DC rapid circuit breaker and is combined with a short circuit current direction identification device so as to implement two corresponding permanent magnetic circuit establishment and conversion devices under the condition with different short circuit current directions. The small-current magnetic blast arc quenching device consists of magnetism leading strips, a strip permanent magnet, arotary connecting rod, a rotating arm, coil electromagnets, a balancing spring and the like. The electromagnets are respectively fixed at the lower sides of both ends of the rotating arm. A command given by the short circuit current direction identification device can control the closed and release states of any one electromagnet to drive the rotating arm to clockwise or anticlockwise rotate. Thecenter of the rotating arm is connected with the center of the strip permanent magnet by the rotary connecting rod and drives the strip permanent magnet to rotate. Both ends of the strip permanent magnet are contacted with two groups of different magnetism leading strip connectors to carry out switching so as to implement the establishment of a magnetic circuit and the switching process of the magnetic circuit direction.

Description

Technical field: [0001] The invention relates to the field of DC fast circuit breakers, in particular to a small-current magnetic blowout arc extinguishing device for DC circuit breakers based on a permanent magnet magnetic circuit conversion method. Background technique: [0002] DC fast circuit breakers generally have the problem that small currents between 5A and 300A cannot effectively extinguish the arc. The reason is that after the small current arc of the DC fast circuit breaker is formed, it cannot enter the arc extinguishing chamber smoothly under the action of the air blow and magnetic blow generated by itself, but continues to burn between the contacts for a long time. The high temperature of the arc that exists for a long time will ablate the surrounding components, and cause the decline of the insulation performance of the components and the failure of the circuit breaker. In severe cases, fire will occur and personal safety will be endangered. [0003] In orde...

AI Technical Summary

Problems solved by technology

However, when the current direction of the main circuit of the circuit breaker changes, the magnetic field direction of the magnetic blowing in the contact area of ​​the circuit breaker should also change. The magnetic blowing coil method can easily realize the commutation of the blowing arc magnetic field through the reversal of the coil current, but for permanent magnets The blowing method needs to solve the problem of the magnetic circuit commutation of the blowing arc field

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