Motor control method, device and system

Abstract

The invention discloses a motor control method, equipment and system. The method includes: receiving a start signal of the motor loss-of-voltage restart function; closing the restart contact of the motor protection device according to the received start signal of the motor loss-of-voltage restart function; If the voltage does not recover after the motor is de-energized within the specified time, open the restart contact of the motor protection device. Because the present invention can realize that the restart contact of the motor protection device is closed after receiving the starting signal of the motor loss-of-voltage restart function, so that when the phenomenon of "shocking electricity" occurs or the contactor has tripped, as long as the voltage recovers within a predefined time When the predetermined value (such as 90% of the rated voltage) is reached, the contactor can be closed, so that the motor can be restarted, thereby providing comprehensive protection for the motor and improving the reliability of the motor operation.

Description

technical field [0001] The invention relates to the field of motor control, in particular to a motor control method, a motor control device and a motor control system. Background technique [0002] The short-term voltage fluctuation or short-point phenomenon of the power grid caused by lightning strikes, short circuits, etc. is called the "swaying electricity" phenomenon, which will cause the contactor to trip (or be called tripping) and cause the motor to stop. At this time, it is generally necessary to restart the motor. Aiming at the phenomenon of "swaying electricity", a motor protection device with a voltage-loss restart protection function is designed. After the "swaying electricity" phenomenon occurs (usually the motor protection device is set when the voltage drops to about 10% of the rated voltage When the motor protection device judges that the voltage has recovered, it can send a pulse command to restart under voltage loss. This command makes the restart contact ...

AI Technical Summary

Problems solved by technology

[0003] However, since the above-mentioned motor protection device in the prior art will only start the loss of voltage restart protection action when the voltage drops to 10% of the rated voltage, when the voltage drops to about 60% of the rated voltage, the motor protection device will not Send a pulse command to restart under voltage loss, but actually the contactor in the motor starting circuit has tripped to stop the motor. Therefore, even if the voltage is restored later in this case, the restart contact of the motor protection device does not receive the command. No action, so that the contactor will not pull in, and the motor cannot be restarted

Images