High-capacity-motor slow-starting protective device

Abstract

The invention discloses a high-capacity-motor slow-starting protective device which includes a motor, an AC power supply, a rectifying circuit, a bidirectional SCR, a unijunction transistor, a transformer, a sliding rheostat, a voltage-stabilizing tube, a fifth diode, a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a first capacitor and a second capacitor. The protective device undergoes current limiting and voltage stabilization by the first resistor after being rectified by the rectifying circuit and then charges the high-capacity capacitors and delays gradual increasing of an opening angle of the bidirectional SCR by triggering pulses through discharge capacity of the sliding rheostat to the unijuction transistor. Even if the resistance of the sliding rheostat is adjusted to the minimum, the bidirectional SCR does not switch on completely immediately so that a soft-starting objective is achieved. Through adjustment of the sliding rheostat, soft starting speed of the motor can be changed. Through adoption of the soft starting, the high-capacity-motor slow-starting protective device is capable of limiting impulse current of a refrigeration motor so that motor burning is prevented, service life of the motor is prolonged and inconvenience brought to work by motor burning is reduced.

Description

technical field [0001] The invention relates to a motor controller device, in particular to a slow start protection device for a high-load motor. Background technique [0002] For a circuit with a high-power motor as a load, because the motor has a large power and low resistance value, the resistance value in the cold state is lower before it is turned on, and the starting current of the motor is very large. Sudden start may cause the phenomenon of burning out the motor, causing the motor to burn out. reduced service life. Contents of the invention [0003] The object of the present invention is to provide a slow start protection device for a high-load motor in order to solve the above problems. [0004] The present invention achieves the above object through the following technical solutions: [0005] The invention includes a motor, an AC power supply, a rectifier circuit, a bidirectional thyristor, a unijunction transistor, a transformer, a sliding rheostat, a volt...

AI Technical Summary

Problems solved by technology

[0002] For a circuit with a high-power motor as a load, because the motor has a large power and low resistance value, the resistance value in the cold state is lower before it is turned on, and the starting current of the motor is very large. Sudden start may cause the phenomenon of burning the motor, causing the motor to burn out. reduced service life

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