Small breaker

Abstract

A small circuit breaker for overcurrent protection and short circuit protection, including contact system, arc extinguishing system, operating mechanism and free trip mechanism, overcurrent protection system, short circuit protection system, etc. By operating the handle, the action of the operating mechanism can drive the movable contact hinged on it to move in the direction of the static contact to connect the circuit; when there is an overcurrent or short-circuit fault, the action of the overcurrent protection system or the short-circuit protection system drives the free tripping mechanism Tripping, the circuit is disconnected; there is an opening on the lever of the operating mechanism, which can be connected to a disconnectable neutral pole through a shaft to realize simultaneous action of the two poles; the upper end of the moving contact can be realized by cooperating with a limiter Quick closing of moving contacts; multiple single-pole miniature circuit breakers are connected together through handles, free tripping mechanisms, etc. to form a multi-pole miniature circuit breaker.

Description

technical field [0001] The invention relates to a miniature circuit breaker for overcurrent protection and short circuit protection. Background technique [0002] Each unit of the miniature circuit breaker includes contact system, arc extinguishing system, operating mechanism and free tripping mechanism, overcurrent protection system, short circuit protection system, insulating shell, operating handle, etc. Through the operating handle, the operating mechanism drives the moving contact in the contact system to make the small circuit breaker turn on and off, and realize the control of the electrical circuit; through the sensing of the thermal effect and magnetic effect of the current, the electrical circuit is overloaded, Protection against faults such as short circuits. [0003] When the moving and static contacts are in contact and there is sufficient contact pressure, the miniature circuit breaker is connected to the electrical circuit, and the local temperature change of...

AI Technical Summary

Problems solved by technology

[0009] In traditional miniature circuit breakers, the operating mechanism and the free tripping mechanism are mechanically connected even after free tripping. When the short circuit is broken, the time is only a dozen microseconds, and the connected mechanism may affect The breaking time of the mechanism, even if it only affects a few microseconds, has a great influence on the arc, and this effect should not be ignored

[0010] In addition, in the arc extinguishing system of the traditional miniature circuit breaker, when the short-circuit current is broken, the arc must complete the transfer from the moving and static contacts to the arc guide plate and the arc strike angle before entering the arc extinguishing chamber, and pass through the arc guide In this process, the arc root of the arc is transferred from the movable contact to the arc guide plate, and the circuit that produces the magnetic blowing effect has a sudden change, and the circuit’s The electrodynamic force of the magnetic blow effect on the arc will also undergo a sudden change. The electrodynamic force of the magnetic blow effect is weakened, and it becomes more difficult for the arc to enter the arc extinguishing chamber through the arc path between the arc guide plate and the arc strike angle.

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