Preparation before motor startup
(1) In order to ensure the normal and safe starting of the motor, the following preparations shall be made before starting generally:
① Check whether the power supply has power and whether the voltage is normal. If the power supply voltage is too high or too low, it should not be started;
② Whether the starter is normal, such as whether the parts are damaged, whether the use is flexible, whether the contact is good, and whether the wiring is correct and firm;
③ Whether the specification and size of the fuse are appropriate, whether the installation is firm, and whether there is fusing or damage;
④ Whether the connector on the terminal block is loose or oxidized;
⑤ Check the transmission device, such as whether the belt is properly tightened, whether the connection is firm, and
whether the bolts and pins of the coupling are fastened;
⑥ Check whether the motor and starter housing are grounded, whether the grounding wire is open circuit, and whether the grounding bolt is loose or falling off;
⑦ Remove the sundries around the motor and remove the dust and oil dirt on the base surface;
⑧ Check whether the loading machine is properly prepared for startup.
(2) For motors that have not been used or stopped for a long time, in addition to the above preparations, the following items shall be checked before installation and startup:
① Check all data on the motor nameplate, such as power, voltage, speed, etc., to see if they are consistent with the actual use requirements;
② Check whether all parts of the motor are complete and well assembled;
③ Check whether the specification and capacity of the starting equipment are consistent with the requirements of the motor;
④ Use a 500V megger to measure the insulation resistance between motor phases and to the ground. The measured insulation resistance shall not be less than 0.5MQ. If it is less than 0.5M O, the motor must be dried or repaired before use;
⑤ Check the installation and calibration quality of the motor;
⑥ Check whether the motor connection is consistent with the nameplate;
⑦ The no-load operation shall be checked first to check whether the rotation direction is correct.
Precautions during startup
① After connecting the power supply, if the motor does not rotate, the power supply should be cut off immediately. Never hesitate to wait, let alone live check the motor fault, otherwise the motor will be burned and dangerous.
② During startup, pay attention to the working conditions of motor, transmission device and load machinery, as well as the indication of ammeter and voltmeter on the line. If there is any abnormal phenomenon, power off and check immediately, and start again after troubleshooting.
③ When starting the motor with manual compensator or manual star delta starter, pay special attention to the operation sequence. The handle must be pushed to the starting position first, and then connected to the running position after the motor speed is stable to prevent equipment and personal accidents caused by misoperation.
④ The motors on the same line shall not be started at the same time. Generally, they shall be started one by one from large to small to avoid simultaneous starting of multiple motors. The current on the line is too large, and the voltage drops too much, which will cause difficulty in starting the motor, cause line fault or make the switchgear switch.
⑤ When starting, if the rotation direction of the motor is reversed, the power supply shall be cut off immediately, and any two of the three-phase power lines shall be exchanged for each other to change the rotation direction of the motor.