The failure of the motor to check electrical engineer

Motor fault check the motor fault processing, all kinds of methods of information on a variety. Some from the principle analysis, some experiences. (see electrical engineer) through experience, from the perspective of combining theory with practice to make specific analysis as follows. One, the motor starting motor not turn also perkins diesel generator no sound. Because the motor power supply or two phase or three phase winding circuit. First check whether there is a power supply voltage. Such as three-phase are no voltage, the circuit fault; If the three-phase voltage balance, fault in the motor itself. At this time to measure the resistance of the three-phase winding motor, find out the fault phase winding. Motor does not turn, but there are "buzzing" sound. Measure the motor terminal, such as three-phase voltage balance and the rating can be convicted of serious overload. Check step is, first remove the load, if the speed of the motor with a normal voice, which can determine overload or load mechanical part is faulty. If still do not turn, usable hand turn the motor shaft, if very tight or turn to be not moved, the three phase current measurement, such as three phase current balance, but may be larger than the motor part rating of the mechanical part of the motor was stuck on the motor oil shortage, bearing rust or damage is serious, end cover or oil cover too oblique, rotor and bore a collision sweep (also called bore). If you turn the motor shaft by hand to feel struggled with a certain way or at the sound of "scrape" cyclical, the chamber can be judged to sweep. 

The reasons are: (1) the bearing clearance between the internal and external ring is too big, need to change the bearing; (2) the bearing chamber (bearing hole) is too big, wear and tear caused by inner hole diameter is too large for a long time. Emergency measures is electroplating a layer metal or jacketed, can also be used in bearing small mark for the indoor walls; (3) the shaft bending, end cover through wear and tear. Motor speed is slow, and accompanied by "buzzing" sound, the shaft vibration. Such as measured one phase current is zero, and the other two phase current is far higher than the rated current, that is two phase operation. The reason for this is a circuit or power supply that open circuit or a motor winding phase circuit. A small motor phase break when available megohmmeter and multimeter or school lamp inspection. Check the star and delta connection of motor, must open the joint of the three-phase winding, whether measured each phase circuit. Medium capacity more than mostly adopts the motor of the winding wire and around many branch in parallel, if broken several root or disconnect a parallel branch is more complex. Often adopt the method of www.dongfeng-motor.com three phase current balance and resistance method, generally three phase current difference (or resistance) value is greater than 5%, the current small resistance (or larger) phase for opening phase. Practice has proved that motor circuit fault occurs at the end, or joint lead winding etc.