Structure of low-voltage circuit breaker
1, the contact system and the arc extinguishing device. Contact system is the executive mechanism of low-voltage circuit breaker, the main contact for the realization of the main circuit is switched on and off, auxiliary contacts the supporting interlock control circuit for the control. The arc extinguishing device for arc main contact.
2, the operating mechanism and free tripping mechanism. Operating mechanism and a free trip is a mechanical transmission part of low-voltage circuit breaker, the main implementation on low voltage circuit breaker main contact and auxiliary contact and disconnected, the operation of the form, the operating handle operating leverage, the electromagnet operation and motor. Automatic release of low-voltage circuit breaker is realized by the short circuit, overload, undervoltage and other three kinds of protection device, when the circuit transmits the fault signal, tripping device corresponding action, the final top main lever up, main lever drive free tripping mechanism and the hook removed, the main contact by the reaction force spring to achieve the role of points fault, circuit is protected.
3, an electromagnetic tripping device. Electromagnetic tripping device is composed of a core and the excitation coil opening.
4, overload release. Overload release by a heating element and a double metal sheet composition. The main contact is closed, the working current flowing through the heating element, when the circuit is in normal operation (working current is not more than the overload setting current value), double metal film is deformed. But not enough to push the main lever. Circuit overload failure occurs, the heat generated by the heating elements increase the double metal plate undergoing large deformations and push the main lever moves up, the main lever driven free trip to breaking the low voltage circuit breaker. Overload, the heating element and the action of the bimetallic strip by the inertia effect and not instantaneous action, the action time and the current value of inverse time characteristic.
5, undervoltage tripping device. Undervoltage tripping device is composed of a core and the excitation coil opening. When external voltage (voltage should be catchy from main contact), under the excitation coil pressure release current flows, the armature is attracted and does not affect the normal branch of low-voltage circuit breaker fault, pressure or low voltage external voltage instability, armature release and push the main lever moves up, the main lever drive free tripping mechanism the breaking of low-voltage circuit breaker, low voltage circuit breaker cannot connect at this time.
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