Lightning surge protection circuit of elevator door motor

Abstract

The invention relates to the field of lightning surge protection, in particular to a lightning surge protection circuit of an elevator door motor. The lightning surge protection circuit is characterized in that the protection circuit is electrically connected between a power supply and an elevator door motor, and includes a first-level protection unit and a second-level protection unit; the first-level protection unit includes a first varistor, a second varistor, a third varistor and a TVS tube unit; the first varistor is connected with a live line and a null line, the second varistor is connected to the live line and connected with the TVS tube unit, the third varistor is connected to the null line and connected with the TVS tube unit, and the TVS tube unit is grounded; and the second-level protection unit includes a first voltage stabilizing diode and a second voltage stabilizing diode, wherein the positive pole of the first voltage stabilizing diode is connected to the positive poleof the second voltage stabilizing diode, the negative pole of the first voltage stabilizing diode is connected to the live line, the negative pole of the second voltage stabilizing diode is connectedto the null line, and the intermediate node of the first voltage stabilizing diode and the second voltage stabilizing diode is grounded. The lightning surge protection circuit of the invention has agood surge protection effect and high reliability.

Description

technical field [0001] The invention relates to the field of lightning strike and surge protection, in particular to a lightning strike and surge protection circuit for an elevator door machine. Background technique [0002] Surge voltage refers to the instantaneous overvoltage beyond the theoretical working voltage range. The possible causes of surge are divided into external reasons and internal reasons: the main source of external reasons is the overvoltage caused by lightning or the switching operation of the public grid. The damage of electrical equipment is related to it; the internal cause refers to the surge of inductive load inside the building; [0003] The surge is mainly caused by two aspects. One is the overvoltage pulse generated at the moment the power is turned on. Due to the non-linearity of the internal circuit of the door machine controller, this overvoltage pulse may generate a peak pulse higher than the power itself; The on-off operation of the external...

AI Technical Summary

Problems solved by technology

[0005] At present, in the application scenario of the elevator, the main power input terminal of the elevator control cabinet and the input terminal of the frequency converter have no anti-surge impact measures; the protective grounding of the elevator is also not good, and many design grounding points (such as control cabinets, The door operator and door operator control system, metal shield, etc.) all have poor grounding conditions similar to the wiring grounding after spraying insulating paint; therefore, when the elevator encounters a large current impact, static electricity or a large electromagnetic field, there will be a fault in the control system. Faulty, even burned out electrical components

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