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Wuxi Lanhai Electric Motor Co.,Ltd

Add: 4#, Tianshi Road Shitangwan Town, Wuxi, Jiangsu, China


TEL: 0086-0510-83269982

FAX: 0086-0510-83269953

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Starting current and operating state of three-phase asynchronous AC motor
Nov 26, 2018

The three-phase asynchronous AC motor starts from the power-on and the speed gradually rises until it is stable. This process is called startup. According to different startup methods, it can be divided into direct startup and buck startup. The starting current of the direct start is large, which has a great influence on the power supply transformer. The squirrel cage asynchronous motor with a large capacity generally adopts a step-down start. The step-down start is to properly reduce the power supply voltage and then add it to the stator winding of the motor to start. When the motor starts or ends, the voltage of the motor is restored to the rated value. The purpose of this is mainly to reduce the starting current, but because of the step-down, the starting torque of the motor will also decrease. Therefore, buck start is only available for no-load or light-load start-up.

Starting requirements for three-phase asynchronous AC motors

1. Direct start with switch: The circuit directly activated by the switch is only suitable for small-capacity motors that are not frequently started. It cannot realize remote control and automatic control, nor can it achieve zero voltage, under voltage and overload protection.

2. Adopting contactor jog control: The contactor point control circuit can be used to control the motor with a slightly larger capacity or frequent starting, and realize the function of “single move, release without moving”.http://www.lanhai-globals.com/