Magnetic protection components of thermal magnetic protection device

Abstract

The invention discloses a magnetic protection assembly of a thermo-magnetic protection device. The thermo-magnetic protection device is applied to a circuit breaker. The magnetic protection assembly comprises a movable iron core, a static iron core and torsion springs. An air gap is arranged between the static iron core and the movable iron core, and the air gap is adjustable; and the torsion springs provide fixation inner counterforce. The springs in the magnetic protection assembly of the thermo-magnetic protection device provide fixation inner counterforce, and the fixation inner counterforce is adjustable, so that the magnetic protection assembly is allowed to be designed with only one parameter, that is, the air gap, being taken into consideration, and the design difficulty is greatly reduced.

Description

technical field [0001] The invention relates to the field of low-voltage electrical appliances, more specifically, to a thermomagnetic protection device in switching electrical appliances. Background technique [0002] The thermal magnetic protection device can protect against overload current and short circuit current. Switching electrical protection such as circuit breakers is usually controlled by thermal magnetic protection devices. Thermal magnetic protection devices are mostly used in small-capacity circuit breakers. Large-capacity circuit breakers with a rated current higher than 1000A mostly adopt electronic protection, that is, the current in the circuit is sensed by the transformer, the current is monitored by the controller, and the action is performed by the magnetic release. In large-capacity circuit breakers with a rated current higher than 1000A, thermal magnetic protection devices are rarely used. [0003] However, in consideration of market demand and use...

AI Technical Summary

Problems solved by technology

The thermal protection component of the traditional thermal magnetic protection device adopts eddy current heating technology, so it is difficult to control, and the number of parts is large, and the cost advantage is poor. In addition, the thrust generated by the deformation of the thermal protection bimetal is usually small. For large The operating mechanism of the capacity circuit breaker requires a large tripping force, so it is difficult for the bimetal to directly push the mechanism to trip

Traditional magnetic protection components need to adjust the spring reaction force and air gap at the same time, so there are two parameter changes in this method, which is difficult to design, calculate and verify, and the spring reaction force adjustment often results in a large adjustment force, which brings inconvenience to users. There are many components in the magnetic protection activation system, and it is difficult to obtain the ideal fast action speed of the circuit breaker

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