When the agricultural motor is in normal operation, the sound is smooth, brisk and uniform; if there is a harsh noise such as screaming, dullness, friction, vibration, etc., the motor has a fault. First of all, it should be judged whether it is mechanical or electrical. The method is: connect the power supply, there is abnormal sound, cut off the power, abnormal sound still exists, it is mechanical failure; otherwise it is electrical fault.

1. The abnormal sound caused by mechanical failure When the agricultural motor is in normal operation, the mechanical noise should be a small “sand” sound. There is no change in height and low friction. There is no metal friction sound, which is the sound of normal bearing operation. Common abnormal sounds caused by mechanical failures are as follows:
1). The “咝咝” sound is the metal friction sound. The smoke is generally caused by the lack of oil dry grinding of the bearing. The bearing should be disassembled to add grease.
2). The “嘎吱嘎吱” sound is the sound produced by the irregular movement of the rollers inside the bearing, which is related to the clearance of the bearing and the state of the grease. If the motor has only this sound and there are no other abnormalities, and the sound disappears immediately after the grease is applied, it is not a malfunction and the motor can continue to be used.
3). “唧里唧里” is the sound produced when the roller or ball is running. If there is no other noise, and the sound is obviously reduced or disappeared after the grease is added, it is generally not a malfunction and the motor can continue to run.
4). There are two possibilities for “咚咚” sound. One is the sudden acceleration of the motor, such as sudden start, stop, and reverse braking. The acceleration torque causes loosening of the rotor core and the shaft. Second, the sound from the transmission mechanism may be caused by looseness between the coupling or the pulley and the shaft, and the key or keyway wear.
5). “嚓嚓” is the noise caused by the motor broom.
6). The periodic “click” sound is caused by the unevenness of the belt joint.

2, the abnormal sound caused by electrical faults 1). Stout "beep" sound, like the squeaking of the squeak is mainly caused by the current imbalance, because the current imbalance will produce two times the load related electromagnetic frequency of the electromagnetic Noise is the main cause of burning of agricultural motors. In this case, stop the machine immediately, and then put it into operation after troubleshooting.
2). “嘶嘶” or “噼啪” discharge sound The stator winding has a slight “嘶嘶” discharge sound when it is in poor contact or leakage, and a “噼啪” discharge sound will occur when it is severe.
3). Mosquito sound The end of the stator winding is not strong or the immersion paint is not good. The whole stator winding end does not form a solid whole, and the individual wires are caused by the electromagnetic force.
4). The metal impact sound when starting, stopping and load changes is generally caused by the looseness of the stator core.
5). Irregular frogs are caused by air gaps or looseness inside the iron core.
6). The shaking sound of the metal is open at the end of the stator, and the open silicon steel sheet vibrates to emit a metal shaking sound.