Motor selection and maintenance
UCCSA Zuohouqi Agricultural Machinery Supervision Station Zhang Zhanhong UAC ZARC Houyou Banner Forestry Bureau Han Cuiping 1 Selection of Electric Motors 1.1 Selection of motor according to the surrounding environment of the motor installation site The common forms of rural electric motors are protected and closed. . The protective ventilation performance is good, the price is low, and it is suitable for the environment where the environment is dry and where there is little dust. If there is more dust and splashes of water droplets, the enclosed motor should be used. Such motors can be used in agricultural and sideline products processing machinery and water pumps. In addition, there is also a sealed motor that can be operated by dipping in water. The electric submersible pump uses such a motor.
1.2 According to the use of load conditions, select the power of the motor The motor power should generally be 1.11.5 times the production machinery power. If the power selection is too large, not only increase investment, but also reduce the mechanical efficiency and increase production costs. If the power selection is too small, the motor will bear an excessive load for a long time, which will cause the temperature to rise too high and damage the insulation, shortening the service life of the motor.
1.3 According to the rotating speed requirements of the working machine and the transmission mode, the matching principle of the motor speed is selected so that both the motor and the production machine run at the rated speed, and the transmission mode is the same.
2 Maintenance of the motor 2.1 Environmental inspection Always check whether any other foreign matter near the motor impedes the normal operation of the motor. Remove dirt, grease, dirt, and other contaminants that affect the heat dissipation of the motor.
2.2 Maintenance of bearings The most important thing is to replace the oil regularly. When changing the oil, clean the bearing with coal or gasoline and carefully inspect the wear condition. If the wear is serious or damaged, replace the new bearing. If the bearing is intact, fill the grease and do not exceed 70% of the bearing capacity.
2.3 Safety Inspection Regularly measure the motor insulation resistance (not less than 0.5 megohms) with a megohmmeter and check the grounding of the chassis. Always check for loose or burned connections. Check the starter regularly to see if the contacts and terminals are loose, burned, and oxidized. If any of the above phenomena should be eliminated in a timely manner.
2.4 Maintenance During the slack season During the slack season, the motor should be fully checked and repaired to ensure normal operation when the production is busy. When the motor is not in use, it should be stored indoors, and be protected against moisture, dust, rat damage, and loss. Keep it properly.
3 Motor Common Faults 3.1 Three-Phase Motor Phase Loss Operation In the operation of a three-phase motor, a certain phase fuse blows or the wire is disconnected and the contact is poor, so that one phase does not supply power, but the motor can continue to operate. At this time, the turning force is obviously reduced, the rotation speed is slow, the sound is abnormal, and the current is large. Over time, the motor will be burned out. If there is a lack of phase before start-up, there will be a “click†sound after the switch is closed. If the motor does not turn, pull the knife off immediately to disconnect the power supply. Check the cause and troubleshoot before starting. Otherwise, it will burn out the motor.
3.2 If the motor temperature is too high If the power supply voltage is too high or too low, the temperature of the motor will increase. During operation, it is necessary to pay attention to whether the temperature rise of the motor exceeds the regulation. If overheating is detected, stop the operation and take appropriate measures to allow the air to circulate, reduce the load, and shut down at noon during the hot season.
If the bearing part is hot and hot, a "beep" or "kekeke" sound may be heard, it may be the bearing burned or damaged, it may be the bearing into the sun or the transmission belt is too tight and so on. The bearing shell should be dismantled for cleaning inspection. If it is damaged, it should be replaced. If the bearing is burned but not damaged, as long as the operation is flexible, it can be used after adding new oil; if the belt is too tight, it should be readjusted.
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