When the motor is running or experiencing a malfunction, it can be promptly prevented and troubleshot through four methods: observation, listening, smelling, and touching. These methods ensure the motor operates safely.
1. Observation
Observe whether there are any abnormalities during the operation of the motor. The main manifestations are as follows:1. If the stator winding is short-circuited, smoke may be observed emanating from the motor.2. When the motor is severely overloaded or running with a missing phase, the speed will slow down and there will be a heavy buzzing sound.3.When the motor is running normally but suddenly stops, sparks may be seen at loose connections, fuses may blow, or certain components may become stuck.4. If the motor vibrates excessively, it may be caused by a jammed transmission device, improper motor fixation, or loose bolts on the base.5. If there are any signs of discoloration, burn marks, or smoke traces on the contact points and connections inside the motor, it indicates potential issues such as local overheating, poor conductor contact, or burnt windings.
2. Listening
When the motor is running properly, it should produce a consistent and gentle buzzing sound without any unusual or specific noises. If there is excessive noise, such as electromagnetic noise, bearing noise, ventilation noise, or mechanical friction noise, it could indicate a potential issue or problem with the motor.1. When it comes to electromagnetic noise, there are several possible reasons if the motor emits a fluctuating and heavy sound. One reason could be an uneven air gap between the stator and rotor. In this case, the sound will fluctuate and the interval between high and low tones will remain the same, indicating that the bearing wear causes the stator and rotor to be eccentric.(2) Imbalance in three-phase current can occur due to various reasons, such as incorrect grounding, short circuit, or poor contact in the three-phase winding. If the sound emitted by the motor is dull, it indicates a severe overload or phase loss operation.2. The bearing noise should be regularly monitored during motor operation. One method of monitoring is to place one end of a screwdriver against the bearing installation position and hold the other end close to the ear to listen to the sound of the bearing rotation.If the bearing is functioning properly, it will produce a continuous and subtle 'shasha' sound, without any fluctuations or metallic friction sounds.
Smelling
In addition to visual inspection, you can also use your sense of smell to detect and prevent motor faults. Open the junction box and carefully smell the motor. Look out for any unusual or burnt odors.
If you detect a distinct paint odor, it indicates that the motor's internal temperature is excessively high. If you notice a strong burnt or charred scent, it may be caused by a punctured insulation layer or burned winding.
Touching
Touching certain parts of the motor's temperature can also help determine the cause of the malfunction. To ensure safety, use the back of your hand to touch the motor's casing and the area around the bearings. If you feel an abnormal temperature, it could be due to the following reasons:Poor ventilation can be caused by fan detachment or blocked air ducts, which can lead to overheating of the stator winding due to excessive current overload.
