A control and protective circuit on control and protective switch electric apparatus

Abstract

A control and protection circuit of a control and protection switching device pertains to the technical field of electric industry. The invention includes a signal sampling circuit, a short-circuit detection circuit, a microprocessor circuit, a magnetic flux converter control circuit and a power converting circuit; the signal sampling circuit sends a current signal to the microprocessor circuit after the amplification and the potential uplifting, the short-circuit detection circuit sends a large range signal in the signal sampling circuit to the microprocessor circuit after the processing, the microprocessor circuit judges whether the short-circuit fault is existed or not, a corresponding control signal is given out and sent to the magnetic flux converter control circuit, the magnetic flux converter control circuit converts the low-level signal which is emitted by the microprocessor circuit to a high-level signal by photoelectric isolation, a magnetic flux converter is driven, the power conversion circuit converts the alternating current high voltage to the direct current low voltage, so as to provide the power for the circuits. The circuit transfer method is simple, the structure is simple, the reliability of the actions is good, the anti-interference capacity is strong, and the invention has the advantages of small size and high reliability when the invention is used for the control and protection switching device.

Description

technical field [0001] The invention relates to a control and protection circuit for a control and protection switching device, which is used in a low-voltage power distribution and control system and belongs to the field of electric technology. Background technique [0002] Control and protection switching appliances integrate the functions of circuit breakers, contactors, thermal relays and isolators into one, and reasonably coordinate the protection and control characteristics of discrete components, and can be widely used in automation Centralized control system and distributed production line control system based on field bus, etc., such as motor control and protection systems in metallurgy, coal mines, steel, petrochemicals, ports, ships, railways, etc., and lighting, power conversion, pumps in modern buildings , fans, air conditioners and other electrical control and protection systems. [0003] At this stage, research and discussion on control and protection switchi...

AI Technical Summary

Problems solved by technology

The power supply of the microprocessor in this circuit is not isolated from the power supply of the flux converter, and the work reliability is poor and the anti-interference ability is poor.

Images