One reason is due to power supply: the voltage is too high or too low. Under specific loads, if the voltage variation range should be outside of+10% to -5% of the rated value, it will cause the motor to overheat; Asymmetric three-phase voltage of the power supply, with an imbalance of more than 5% between phases, can cause overheating of the winding; Experience has shown that over 85% of the burning of agricultural motors is caused by phase loss operation. Therefore, phase loss protection devices should be installed on the motors. Secondly, there are reasons for the water pump: the selection of power is not matched, the small horse pulls the big car, and the electric motor is overloaded for a long time, causing the temperature of the electric motor to be too high; Motors that start too frequently and are rated for short-term or intermittent duty operate continuously. The number of starts should be limited, thermal protection should be selected correctly, and used according to the rated values specified on the motor. The third reason is the motor body: incorrect connection, mistakenly connecting the △ shape to the Y shape, causing the temperature of the motor to rapidly increase; The stator winding has phase to phase short circuit, turn to turn short circuit, or local grounding. In mild cases, the motor may overheat locally, and in severe cases, the insulation may be burnt out; The squirrel cage rotor has broken bars or defects, and the motor runs for 1 to 2 hours, resulting in a rapid increase in iron core temperature; If there is a malfunction in the ventilation system, it is necessary to check whether the fan is damaged, whether the rotation direction is correct, and whether the ventilation duct is blocked; The wear of bearings and the eccentric cleaning of the rotor cause a metal impact sound when the stator and rotor iron cores collide, causing the temperature of the iron core to rapidly rise. In severe cases, the motor may smoke and even the coil may be burned. The fourth reason is due to the working environment: the motor winding is affected by moisture, dust, oil stains, etc., which adhere to the winding, resulting in a decrease in insulation. The insulation resistance of the motor should be measured and cleaned and dried; The ambient temperature is too high. When the ambient temperature exceeds 35 ℃, the high inlet air temperature can cause the temperature of the motor to be too high. Efforts should be made to improve its working environment. For example, setting up a shed to shade the sun. Attention: If a malfunction occurs due to electrical reasons, it should be repaired by an electrician who has obtained a professional qualification certificate. People with limited knowledge should not blindly repair to prevent personal injury accidents.