When the motor is in operation, the duty staff can monitor its operation through instruments and sensory organs in order to find out the problem early and reduce or avoid the occurrence of malfunction.

3.3.1 Monitor the temperature of the motor

The motor will heat up in normal operation and make the motor temperature rise, but it should not exceed the allowed limit. If the load of motor is too big, the temperature of environment is too high, the ventilation is not good or the fault occurs in the operation, the temperature will exceed the allowed limit and cause the winding to

Therefore, the temperature of the motor is the main symbol to reflect the operation of the motor, and it should be checked frequently during the operation. To judge whether the motor is overheated, the following methods can be used.

(1) By the feeling of hand: if you touch the shell with your hand, there is no hot feeling, it means the temperature of the motor is normal; if you put your hand on it and retract it immediately, it means the motor is overheated.

(2) Put 2-3 drops of water on the shell of the motor, if there is only hot air and no sound, it means the motor is not overheated; if the water drops are vaporized rapidly with "sizzling" sound, it means the motor is overheated.

(3) The accurate way to tell whether the motor is overheated or not is to measure it with a thermometer.

If you find that the motor is overheated, you should stop and check it immediately, and then use it again after finding out the cause and eliminating the fault.

3.3.2 Monitor the current of the motor

Generally, motors with larger capacity should be equipped with ammeter to monitor its current at any time. If the current size or three-phase current imbalance exceeds the allowed value. It should stop and check immediately. Motors with small capacity are generally not equipped with ammeter, but they are often measured with clamp meter.

3.3.3 Monitor the voltage of the motor

Install a voltmeter and a changeover switch on the power supply of the motor to monitor its three-phase power supply and voltage. The motor's power supply voltage is too high, too low or the three-phase voltage is unbalanced, especially the three-phase power supply is out of phase, it will bring bad consequences. If you find this situation, you should stop the motor immediately and use it again after finding out the reason and removing the fault.

3.3.4 Pay attention to the vibration, sound and smell of the motor

When the motor is running normally, it should be smooth, brisk and without abnormal smell and sound. If violent vibration, noise and smell occur, stop the motor for inspection and repair.

3.3.5 Pay attention to the inspection of the transmission device

When the motor is running, always pay attention to check whether the pulley or coupling is loose, whether the transmission belt is too tight, too loose, etc. If so, it should be stopped and tightened or adjusted.

3.3.6 Pay attention to the working condition of the bearings

Motor operation should pay attention to the bearing sound and heating situation. If the bearing sound is not normal or overheating, check whether the lubrication is good and there is no wear.

3.3.7 Pay attention to the slip ring of AC motor or commutator spark of DC motor

When the motor is running, there will be sparks between the brush and commutator or slip ring. If the spark is larger than a certain limit, especially when the red arc spark is discharged, it will have a destructive effect and must be corrected in time.