1. Preparations before installing the motor The safety performance, electrical performance and mechanical performance of the newly installed or idle motor for more than three months must be checked before use to ensure the safe and reliable operation of the motor. 1. Check the insulation resistance of the motor windings. Open the junction box. Use a megohmmeter above 500V to measure the insulation resistance between the winding and the base. The normal resistance value should be> 5M ohm. Remove the connecting piece of the terminal block and measure the insulation between the winding phases. The normal resistance value should be> 10M ohm. If in the above measurement process, the resistance value is seriously low once, the motor should be disassembled to find the cause. If there is no fault point, it means that the insulation performance of the motor is degraded due to damp, and it should be baked to drive the damp until the insulation is qualified before installation and use. 2. Measure the resistance of the three-phase winding. Observe whether the resistance values are the same. If there is a large difference in resistance value, check whether the motor winding leads have poor contact or other reasons. 3. Check whether the mechanical part of the motor is qualified. Rotate the shaft by hand to check whether it is flexible, whether there is abnormal friction, jamming, shaft shifting and abnormal noise. At the same time, check whether all parts are complete and whether the solid screws are tightened. Whether the coupling or pulley is installed and calibrated well. 2. Motor installation and trial operation Before wiring the motor, check whether the control circuit and protection circuit are normal, whether the fuse is selected properly, and whether the connection points between the control appliances are firm. If it is normal, connect the motor power and start without load, and observe whether the direction of the motor meets the requirements of the equipment. If the direction of rotation is opposite, you only need to swap any two of the power supply wires of the motor terminal board. After the start-up test is normal, connect the motor to the load for trial operation, and check whether its working current is normal. If the current is too large, stop the machine for inspection. If the motor does not rotate, the speed is very low, or there is an abnormal hum after the load is loaded, the power should be turned off immediately. If the power-on time is a little longer, it is very likely to burn the motor windings, or even damage the control circuit and damage the equipment. Condition, the mechanical cause is overload or jamming, and the electrical cause is open-phase operation. At this time, the cause of the failure should be carefully checked, and the trial operation can only be performed after the failure is eliminated. Generally, the starting current of the motor is 5 to 7 times of the running current. When starting the motor, the number of consecutive starts should be controlled within three times to avoid the accumulation of high temperature caused by excessive starting current and burn out the motor winding insulation. Third, the maintenance of the motor during operation Whether the motor is running normally can be judged from the sound, speed, temperature, working current and other phenomena of the motor. If there is a leakage of electricity in the running motor, the speed will suddenly drop and severe vibration will occur. If there is any abnormal noise, overheating and smoking, or control of electrical contacts igniting and smoking, power off immediately and shut down for maintenance. Listen to the sound of the motor when it is running. If you find a loud buzzing sound, it is either a large current or a lack of phase operation. If there is an abnormal friction sound, the bearing may be damaged or bored. If there is a slight abnormal sound, use a wooden stick or a long rod screwdriver, with one end touching the motor bearing part and one end close to the ear, and carefully distinguish whether the sound is abnormal. If there is an abnormal noise, it indicates that the bearing is defective and should be replaced in time to avoid damage to the bearing cage, causing friction between the rotor and the stator, and burning the stator windings of the motor. Observe whether the control electrical contacts and motor wiring contacts are loose, abnormally heating up or sparking, and whether the insulation is aging. Whether the contactor has abnormal vibration or sound, whether the contact is igniting after the contact is closed, if such problems are found, they should be dealt with as soon as possible to avoid accidents. During regular inspections, always check whether the motor is overheated. Commonly used E-pole insulated motors allow a maximum temperature of 105%: the actual motor winding temperature is much lower than this limit temperature. When measuring, the surface temperature of the motor plus 15-20 ℃ is the actual temperature of the motor windings. For the motor with excessive temperature rise, the working current should be measured. If the current is too large and the three-phase voltage is normal, it means that the load is too heavy. The mechanical equipment should be checked by the mechanic. If the motor is found to have overcurrent of more than 20% for a long time, the protection device No action, no automatic power off, which means that the setting value of the thermal relay setting current is too large, and the setting current value should be reduced. Fourth, the disassembly and maintenance of the motor Motor disassembly steps: use a puller to remove the pulley or coupling, remove the tail wind cover of the motor, and remove the front bearing cover screws and the front and rear cover screws. For larger motors, before disassembling, mark the two end caps and the base with a drawing needle, mark the original fixed position, and knock the top of the front axle with a wooden hammer to loosen the rotor and rear cover from the base. , And then remove the rotor from the stator. Be careful when taking the rotor, and don't let the rotor scratch the insulation of the stator winding end. Observe whether the motor bearings are damaged, and whether the lubricating oil has deteriorated and dried up. Grasp the outer ring of the bearing and shake it back and forth to see if it is too loose. If the bearing is normal, there is no need to disassemble it. Use kerosene or diesel to clean the bearing. If there is any problem in the inspection, remove the bearing with a puller. If the shaft and the bearing are too tightly matched or rusted, heating can be used to solve the problem. Wrap the shaft with asbestos rope, heat the bearing quickly and evenly to about 250 ℃ with a blowtorch oxyacetylene flame, and pull it out with a pull tool while it is hot. The cold disassembly method is: pad the bottom of the damaged bearing with a wooden block, break the periphery with an iron hammer, after removing the outer ring, use a hand-held grinder to cut the inner ring of the bearing (no need to cut through to avoid damage to the rotor Journal), and then hit the inner ring with a hammer to rupture the incision and take out the inner ring. When replacing the bearing, it is easy to scratch the rotor journal when it is installed directly. Generally, smaller bearings can be installed directly. When installing and replacing larger bearings, it is best to put the bearings in an oven and heat them. When the temperature reaches about 100 ℃, put the bearings on the rotor journal while it is hot, and use steel pipes to cover them. On the shaft, against the inner ring of the bearing, evenly beat the steel pipe to make the shaft go in place. Note: When installing the bearing, the bearing engraved with the model number side should be facing outwards for future checking and replacement. Add lubricating grease according to half of the space capacity in the bearing. If the speed is high, add a little less, and if the speed is low, add a little more. Excessive lubrication will cause the lubricating oil to become thinner and flow out when the bearing is overheated, which will be swept on the stator windings by the wind blades in the rotor, which will reduce the insulation performance between the windings, cause breakdown and short circuit, and burn the motor windings. Commonly used lubricating oils include calcium-based grease, sodium-based grease, and lithium-based grease. Calcium-based grease has good water resistance, but poor heat resistance (≤ 70 ℃), sodium-based grease has good heat resistance (≤ 120%: ), but poor water resistance. Lithium-based grease has the advantages of the above two, but the price is higher. Please refer to the hardware manual for the introduction of the use of grease. Users can choose according to actual needs. Pay attention to the cleanliness of the grease, do not let it be mixed with dust, iron filings, sand particles, if the contaminated grease is added to the bearing, it will cause the bearing to wear faster and damage the bearing in advance. In short, there are many cases where the motor windings are burnt due to the rotor sweeping due to the damage of the bearing, which should be paid attention to. Five, the daily maintenance of the motor Routine maintenance is very important to reduce and avoid motor failures during operation. The most important link is to patrol inspections and promptly eliminate the root causes of any abnormal phenomena. After an accident, carefully analyze the accident and take countermeasures to reduce The number of accidents and the technical work necessary to improve the operating efficiency of the motor when repairing the shutdown platform. The daily maintenance of the motor is very important for its normal operation, but the motor in operation often encounters many unexpected situations, such as short circuit, overload, and failure. Equal. In order to prevent the motor from being damaged under these conditions, some operation protection measures must be taken. Keep the motor clean. Do not allow water droplets, oil, dust, etc. to enter the motor, and regularly remove the dust inside and outside the motor. Note that the load current should not exceed the rated value. Pay attention to check the bearing heating, oil leakage, etc., especially to refuel according to the regulations. The temperature rise of the motor cannot exceed the rated value. 1. Listen to the sound of the motor. If the sound of the motor is abnormal, replace the bearing immediately. When replacing the bearing, make sure that the accuracy of the shaft and the bearing chamber is damaged. 2. Check the temperature of the motor regularly. If the temperature of the motor is too high, stop or reduce the load. If the temperature is high under normal load, check whether the insulation is damaged. 3. Regularly add oil to the bearings of the motor, and clean the fan and casing. The specific time depends on the working environment. 6. Regular maintenance and maintenance of the motor In order to ensure the normal operation of the motor, in addition to the normal use according to the operating procedures, and the normal monitoring and maintenance during operation, regular inspections and maintenance of the motor should also be carried out. This can eliminate some faults in time, prevent malfunctions, and ensure the safe and reliable operation of the motor. The interval of regular maintenance can be determined according to the form of the motor in consideration of the use environment.