In the process of using three phase asynchronous motors, as long as we keep watching, listening, touching and measuring, most of the failures can be prevented and avoided, and the loss of spare parts and repair costs can be reduced. The motor should be maintained periodically.
1, look: every day when we patrol, we can see the size and change of the working current of the motor, and see if there is any leakage or dripping around it, which will cause the breakdown of the motor insulation and burn it down. Do you have to see if there is an object that affects the ventilation and cooling environment on the periphery of the motor? Do you need to see if the fan end cover, the fan blade and the motor need to be clean? To ensure the cooling effect of cooling. No matter who finds out the problem, it should be dealt with in time.
2, measurement: when the motor runs, it can measure its three-phase working voltage and current, and see if it is balanced. The voltage should be equal, each phase current and the average value of the error should not exceed 10%, such as the use of clamp meter measured the phase current difference is too large, it may have the interturn short circuit.
3, touch: use the back of the hand to explore the temperature around the motor. Under the condition of good bearing condition, the temperature of the common ends will be lower than the temperature in the middle winding. If the temperature of the bearings at both ends is high, the bearing should be checked in combination with the sound condition of the bearing measured. If the overall temperature of the motor is high, it should be treated with the working current to check the load, equipment and ventilation of the motor.
4, listen carefully and carefully listen to the abnormal running noise of the motor. Because the noise of the engine room is large, it can be heard close to the ends of the motor by means of a screwdriver or a listening rod and other auxiliary tools, so as to avoid the motor bearing's lack of oil and dry grinding, and block up, go round the circle, and sweep the chamber to burn out.
The disintegration of large motor bearing replacement difficulties, will adopt bearing type, regular (750 - 1500 hours) with oil gas should pay attention to the use of special lubricating grease and the lower end of the motor, oil discharge outlet is opened or the other side of the bulkhead screws, so as to change the old oil squeeze out (note according to the type of motor quota of supplementary lubrication fat) to prevent the gas due to pressure a lot of oil squeezed to the motor, running splashing into the rotor, the motor cooling effect function. When the grease is added to the grease, the motor should be rotated on the side of the oil to make the grease evenly distributed on the bearing, or the grease is added to the motor when the motor runs.
The 5. is: not only to take timely remedial measures for the problems found in the inspection, but also to tighten up the screws, wiring, dismantling, inspection, cleaning and maintenance of the motor according to the maintenance period (monthly). If the motor end cover 4 fixed screws are loose, will cause the sweeping operation damage; virtual connection, resulting in phase burn motor wiring loose bolts; the motor fan leaves off against the body caused by plugging burnt out; motor bearing lubrication, high operating temperature, without timely supplement or replace the bearing lubricant caused by motor burn.
6., most of the motor failures are caused by phase loss, overload, human factors and motor itself. The circuit part must be checked before starting, and the three-phase current should be checked if the startup is completed. The quality of the working environment determines the maintenance cycle of the motor. The humidity is big, the dust is much, the working environment in the open air should be regularly checked and maintained. The recommendations of the poor working environment are checked once a month to see if the connection is loose, the bearing is damaged, and the oil is lacking. Through systematic analysis, taking corresponding measures and doing regular inspections, we can reduce motor failures and accidents, thereby improving the efficiency of motor use. In the normal operation and maintenance process, we should sum up our experience and know the locations and causes of motor faults. Regular inspections can ensure the safe and reliable operation of motors.