When the motor is running or malfunctioning,You can prevent and eliminate faults in time by looking, listening, smelling, and touching four methods.
To ensure the safe operation of the motor.
one look
Observe whether there is any abnormality during the operation of the motor, which is mainly manifested in the following situations.
1. You may see smoke from the motor when the stator winding is short-circuited.
2. When the motor is seriously overloaded or running with phase loss, the speed will become slower and there will be a heavy "humming" sound.
3. The motor maintenance network is running normally, but when it stops suddenly, sparks will be seen at the loose connection; the fuse is blown or a part is stuck.
4. If the motor vibrates violently, it may be that the transmission device is stuck or the motor is not fixed properly, the foot bolts are loose, etc.
5. If there are discoloration, burn marks and smoke traces at the contact points and connections in the motor, it means that there may be local overheating, poor contact at the conductor connection or burning of the windings.
2. Listen
The motor should emit a uniform and light "humming" sound during normal operation, with no murmurs and special sounds.
If the noise is too large, including electromagnetic noise, bearing noise, ventilation noise, mechanical friction noise, etc., it may be a harbinger of failure or failure phenomenon.
1. For electromagnetic noise, if the motor makes a heavy and high-pitched sound, the reasons may be as follows:
(1) The air gap between the stator and the rotor is not uniform. At this time, the sound fluctuates high and low and the interval between high and low sounds is unchanged. This is caused by the wear of the bearing, which makes the stator and the rotor not concentric. (We recommend that you pay attention to the "Mechanical Engineer" public account, and master the knowledge of dry goods and industry information as soon as possible)
(2) The three-phase current is unbalanced. This is due to the faulty grounding, short circuit or poor contact of the three-phase windings.
(3) The iron core is loose. During the operation of the motor, the iron core fixing bolts are loosened due to vibration, which causes the iron core silicon steel sheet to loosen and emit noise.
2. For the bearing noise, it should be monitored frequently during the operation of the motor.
The monitoring method is: put one end of the screwdriver against the bearing installation part, and the other end is close to the ear, and the sound of the bearing running can be heard. If the bearing is running normally, the sound will be continuous and small "rustling" sound, and there will be no sudden high and low changes and metal friction sound.
If the following sounds appear, it is abnormal:
(1) There is a "squeak" sound when the bearing is running. This is the sound of metal friction, which is generally caused by the lack of oil in the bearing. The bearing should be disassembled and added with appropriate amount of grease.
(2) If there is a "chirp" sound, this is the sound when the ball rotates, which is generally caused by dry grease or lack of oil, and an appropriate amount of grease can be added.
(3) If there is a "click" sound or a "crunch" sound, it is the sound caused by the irregular movement of the balls in the bearing, which is caused by the damage of the balls in the bearing or the drying of the grease if the motor is not used for a long time.
3. If the transmission mechanism and the driven mechanism emit a continuous sound instead of high and low, it can be dealt with in the following situations.
(1) Periodic "crack" sound is caused by the uneven belt joint.
(2) Periodic "dong dong" sound is caused by loose coupling or pulley and shaft and wear of key or keyway.
(3) The uneven collision sound is caused by the collision of the fan blades against the fan cover.
Three, smell
It is also possible to judge and prevent malfunctions by smelling the smell of the motor.
Open the junction box and sniff
Check to see if there is a burnt smell. If a special paint smell is found, it means that the internal temperature of the motor is too high; if a heavy sticky smell or burnt smell is found, it may be that the insulation layer maintenance net has been broken down or the winding has been burned.
If there is no smell, it is also necessary to use a megohmmeter to measure the insulation resistance between the winding and the shell is less than 0.5 megabytes, and it must be dried. The resistance value is zero, indicating that it has been damaged.
Fourth, touch
Touching the temperature of some parts of the motor can also determine the cause of the fault.
To ensure safety, use the back of your hand to touch the motor housing and parts around the bearing.
If abnormal temperature is found, the reasons may be as follows:
1. Poor ventilation. For example, the fan falls off, the ventilation duct is blocked, etc.
2. Overload. Resulting in excessive current and overheating of the stator windings.
3. The stator winding is short-circuited between turns or the three-phase current is unbalanced.
4. Frequent starting or braking.
5. If the temperature around the bearing is too high, it may be caused by bearing damage or lack of oil.
Motor bearing temperature regulations, abnormal causes and treatment
The regulations stipulate that the maximum temperature of rolling bearings does not exceed 95 ℃, and the maximum temperature of sliding bearings does not exceed 80 ℃. And the temperature rise does not exceed 55 ℃ (the temperature rise is the bearing temperature minus the ambient temperature during the test).
Causes and treatment of bearing temperature rise too high:
(1) Reason: the shaft is bent and the center line is not allowed.
Treatment: Find the center again.
(2) Reason: The foundation screw is loose.
Remedy: Tighten the foundation screws.
(3) Reason: The lubricating oil is not clean.
Treatment: Replace the lubricating oil.
(4) Reason: The lubricating oil has been used for too long and has not been replaced.
Treatment: Clean the bearing and replace the lubricating oil.
(5) Reason: The balls or rollers in the bearing are damaged.
Treatment: Replace the bearing with a new one.
Solution:
1. Open the module cover and replace the damaged fuses, charging resistors and other components in the module.
2. Replace the damaged optical sub-board or protection diode.
3. The optical fiber is connected normally according to the mark, and if the optical fiber is damaged, replace it.
4. Replace the module power board.
