Learn - Jun. 30, 2020
9. Supporting power motor overheating
The first reason is the reason for the power supply: the slurry pump voltage is too high or too low. Under a specific load, if the voltage fluctuation range should be outside +10% to -5% of the rated value, it will cause the motor to overheat; the three-phase voltage of the power supply Asymmetry, the unbalance degree of the three-phase power voltage of the power supply exceeds 5%, which will lead to overheating of the winding; lack of phase operation, experience shows that more than 85% of agricultural motors are burned due to lack of phase operation, and the lack of phase protection device should be installed on the motor.
The second reason is the reason for the water pump: the power is not matched, the small horse-drawn cart, the motor is overloaded for a long time, and the motor temperature is too high; the motor is started too frequently, and the motor is rated for short-term or intermittent work. The number of start-ups should be limited, the thermal protection should be selected correctly, and it should be used according to the fixed quota on the motor.
The third reason is the reason of the motor itself: wrong connection method, the wrong connection of the △ shape into Y shape so that the temperature of the motor rises rapidly; the stator winding has interphase short circuit, inter-turn short circuit or local grounding, and the motor is locally overheated when serious, serious The insulation is burned out; the rotor bar of the squirrel cage is broken or there is a defect. The temperature of the iron core rises rapidly after the motor runs for 1 to 2 hours; if the ventilation system fails, you should check whether the fan is damaged, the direction of rotation is correct, and the slurry pump ventilation holes are blocked; Bearing wear and rotor eccentric bore sweep make the fixed rotor iron cores rub against each other to produce a metal impact sound, the temperature of the iron core rises rapidly, and the motor smokes or the coil is burned out in severe cases.
The fourth reason is the reason for the working environment: the motor winding is wet or dust, oil, etc. adhere to the winding, resulting in reduced 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 temperature of the inlet air is high, which will make the temperature of the motor too high. Try to improve its working environment. Such as shelter from the sun. Note: If a fault occurs due to electrical reasons, an electrician who has obtained a professional qualification certificate should repair it. Those who know nothing about it should not blindly repair it to prevent personal injury accidents.
10. Short bearing life
There are four main reasons: ①The motor shaft is not symmetrical or parallel to the pump shaft. The motor shaft or pump shaft should be adjusted, and if the shaft is deformed or bent, replace the shaft directly. ②The bearing assembly is unreasonable. Reassemble the bearing and shaft, or replace the bearing. ③There is friction in the pump or the impeller is out of balance. The friction should be eliminated or a new impeller should be replaced. ④Lubrication is not good. Excessive or too little impurities will lead to short bearing life, the bearing should be taken out and cleaned before use.
The above information is provided by the sewage pump manufacturer.
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