1. Reasons: pump is the power is not complete, small horse cart, motor overload long time operation, the motor temperature is too high; the motor start too often fixed for the short-term or intermittent work system of continuous work. Should limit the number of start, the correct choice of thermal protection, according to the fixed use of motor calibration.
2. The reason is: the motor connection errors, the triangular error connection into a Y shape, the motor temperature rises rapidly; stator winding interturn short circuit, phase short-circuit or local earthing, light motor overheating, severe burn insulation; squirrel cage rotor bar broken or defective, motor run for 1 to 2 hours, the core temperature increases rapidly; failure of ventilation system, should check whether the fan is damaged, the rotation direction is correct, ventilation channel is blocked; bearing wear, eccentric rotor stator and rotor core make sweeping rub a clang, core temperature rises rapidly, serious motor coil burning smoke, even.
3.The reason is: the power supply voltage is high or low, under specific load, if the voltage range in the rated value + 10% to - 5% outside the motor will cause overheating; power three-phase voltage asymmetry, power supply voltage and three-phase electric unbalance degree is more than 5%, will lead to winding overheating; phase operation experience that is more than 85% of agricultural motor burned due to phase operation, with installation of motor open phase protection.
4.Is the reason for the work environment: the motor winding damp or dust, oil and other attached to the winding, resulting in reduced insulation. The insulation resistance of the motor should be measured and cleaned and dried; the environment temperature is too high. When the ambient temperature exceeds 35 degrees, the inlet air temperature is high, the temperature of the motor is too high, so we should try to improve the working environment. Such as scaffolding shade. Note: for electrical fault reasons, please obtain professional qualification certificate in electrical maintenance, little knowledge of the people should not blindly maintenance, to prevent the occurrence of personal injury accidents.