Contactor direct-current pull-in and holding circuit

Abstract

The invention relates to a contactor direct-current pull-in and holding circuit. The circuit is provided with an alternating-current input end, a direct-current output end and five main circuit modules which are a main loop circuit, a thyristor separation driving circuit, a zero crossing point detection circuit, a power-on delay circuit and a delay triggering circuit respectively, wherein the main loop circuit is composed of a rectifier bridge B1, a thyristor TR1 and a voltage dependent resistor RV1, the thyristor separation driving circuit is composed of a resistor R3, a resistor R4, a resistor R17, a resistor 23, an optocoupler O1 and a triode Q3, the zero crossing point detection circuit is composed of a rectifier bridge B2, a voltage stabilizing tube Z3, a resistor R5, a resistor R6, a resistor R7, a resistor R8 and an integrated operational amplifier U2B, the power-on delay circuit is composed of a diode D2, a resistor R9, a resistor R10, a resistor R11, a capacitor C4, a capacitor R5 and an integrated operational amplifier U2A, and the delay triggering circuit is composed of a resistor R12, a resistor R13, a resistor R14, a resistor R15, a resistor R16, a capacitor C1, a capacitor C2, a capacitor C3, a diode D3, triodes Q1 and Q2 and an integrated circuit U1. According to the circuit, electromagnetic power consumption of a contactor is effectively reduced, and pull-in pulsation and noise of the contactor are eliminated.

Description

technical field [0001] The invention relates to a contactor pull-in circuit, in particular to a contactor DC pull-in and holding circuit. Background technique [0002] At present, contactors are one of the most commonly used low-voltage electrical appliances in various power supply occasions in daily production and life. They are mainly used for long-distance frequent on-load switching on and off AC circuits of the main circuit. Most of the existing contactors adopt AC operation, that is, directly control the on-off of 220V or 380V AC to realize the pull-in and release of the contactor. The advantage of this method is that the structure and control are relatively simple, but it has the following disadvantages that are difficult to overcome: [0003] (1) The AC operation contactor consumes a lot of power. Due to the AC operation, an alternating current flows through the electromagnetic system of the contactor, which will cause a large loss of the electromagnetic of the cont...

AI Technical Summary

Problems solved by technology

Due to the use of AC operation, alternating current flows through the electromagnetic system of the contactor, which will cause a large loss in the electromagnetic of the contactor.

[0004] (2) There is a noise problem in the AC operation contactor

Due to the use of AC operation, the magnetic field of the contactor also has the problem of commutation, which leads to large fluctuations in the attraction force of the contactor

[0005] (3) AC operation contactors have high environmental requirements

Because the suction force is weak when reversing, the contactor has higher requirements on the contact surface of the upper and lower armatures. If the contact surface is not clean, it will lead to greater noise and a greater drop in suction force.

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