When the agricultural motor is running normally, the sound is smooth, brisk and uniform; if there are harsh noises such as screaming, dullness, friction, vibration, etc., it indicates that the motor is malfunctioning. First of all, it should be judged whether it is caused by mechanical or electrical reasons. The method is: connect the power supply, there is abnormal sound, and cut off the power, if the abnormal sound still exists, it is a mechanical failure; otherwise it is an electrical failure. 1. Abnormal sound caused by mechanical failure. The mechanical noise of the agricultural motor should be a small "rustle" sound during normal operation. There is no change of high and low, and there is no metal friction noise, which is the sound of normal operation of the bearing. The common abnormal sounds caused by mechanical faults are as follows: (1) "Beep" sounds are metal friction sounds; fumigation is generally caused by the lack of oil and dry grinding of bearings, and the bearings should be disassembled and added with grease. (2) The "creak" sound is the sound produced by the irregular movement of the rollers in the bearing, and it is related to the bearing clearance and the state of the grease. If the motor has only this sound and no other abnormal phenomena, and this sound disappears immediately after the grease is added, it is not a malfunction and the motor can still be used. (3) The sound of 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 significantly reduced or disappeared after the grease is added, it is generally not a fault and the motor can continue to run. (4) There are two possibilities for the squeak sound. One is that the acceleration torque causes the rotor core and the shaft to loosen the coupling when the motor suddenly starts, stops, or reverses the brake. The second is the sound from the transmission mechanism, which may be caused by looseness between the coupling or the pulley and the shaft, and wear of the key or keyway. (5) "Beep" is the noise caused by the motor bore. (6) The periodic "snap" sound is caused by the unevenness of the belt joint. 2. Unusual sounds caused by electrical faults (1) The sturdy "buzz" sound, like the sound of a cow sirloin, is mainly caused by the current imbalance, because when the current is unbalanced, an electromagnetic of twice the power frequency related to the load is generated Noise is the main reason for the burnout of agricultural motors. In this case, stop the machine immediately and put it into operation after troubleshooting. (2) "Hissing" or "cracking" discharge sound A slight "hissing" discharging sound is generated when the stator winding is slightly in poor contact or leaks, and a "cracking" discharge sound may occur in severe cases. (3) The ends of the stator windings of mosquitoes are not bundled well or the paint is not well impregnated. The ends of the entire stator windings do not form a solid whole. Individual wires are caused by vibration under the action of electromagnetic force. (4) Metal impact sounds during start, stop and load changes are generally caused by loose rotor cores. (5) Irregular frogs call for air gaps or looseness inside the iron core. (6) Metal jitter sound The iron chip at the end of the stator is opened, and the open silicon steel sheet vibrates to give out a metal jitter sound.