Phase loss detection method for three-phase motor and detection circuit

Abstract

The invention discloses a phase loss detection method for a three-phase motor and a detection circuit. The phase loss detection method for the three-phase motor comprises the steps of inputting a test current which is less than a starting current of the three-phase motor to the three-phase motor before the start of the three-phase motor; detecting a current value of a winding of the three-phase motor; determining whether the detected current value is less than or equal to a preset current value; and determining phase loss of the three-phase motor when the detected current value is less than or equal to the preset current value. Power supply for the three-phase motor is stopped when phase loss of the three-phase motor is determined. The phase loss detection method for the three-phase motor and the detection circuit are used for solving the problem that a phase loss detection method for the three-phase motor cannot effectively protect the three-phase motor in the prior art, thereby improving the effect of timely protection of the three-phase motor.

Description

technical field [0001] The invention relates to the field of detection, in particular to a detection method and a detection circuit for phase loss of a three-phase motor. Background technique [0002] Existing three-phase motors only detect the current flowing through the three-phase windings of the three-phase motor during operation. The phase motor is out of phase. However, this detection method cannot effectively protect the three-phase motor when it is started. When the three-phase motor is starting, if there is a phase that is not connected or has poor contact between the three-phase motor and the frequency converter, the three-phase motor is prone to failure or even damage during the starting process. Take the compressor as an example. If there is a phase disconnection or poor contact between the DC inverter compressor and the inverter, then when the compressor starts, the compressor will lose control due to lack of phase and overcurrent will occur. Protection, will...

AI Technical Summary

Problems solved by technology

[0004] The main purpose of the present invention is to provide a detection method and a detection circuit for the lack of phase of a three-phase motor, so as to solve the problem that the detection method for the lack of phase of a three-phase motor in the prior art cannot effectively protect the three-phase motor

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