A short circuit is almost fatal to the windings of motor products. Turn-to-turn, phase-to-phase and ground faults are different manifestations of short circuits in windings. According to the actual physical distribution of the winding, the winding part and the end of the groove after the short circuit fault, the degree of damage to the winding is not the same.
In comparison, because of the support or protection of the core groove and the wedge, the derivative hazard of the winding failure hazard is relatively small, but the fault hazard at the end of the winding will be much greater.
When the motor is short-circuited, the end of the winding is subjected to the electromagnetic force radially outward and the axial inward at the same time, and the direct consequence is that the end of the winding expands outward, and the fault of the notch position occurs or is aggravated; the end of the rotor is subjected to the electromagnetic force radially inward,
If it is a cast aluminum rotor, the harm is not obvious, but for the winding rotor, the end may also occur a greater hazard.
Therefore, the size, binding and insulation curing of the motor winding end are very necessary, and for the stator and rotor winding ends of large motors, the stator end clamp and rotor bracket are necessary protection parts for the winding.
The large current caused by the sudden short circuit will produce a large electromagnetic torque, which may cause a large jitter effect of the motor, which may have a negative impact on the dragged equipment, so it is also necessary for the fixation of the motor application process.
In addition to the above hazards, the high current caused by the short circuit will make the winding heat up seriously, but due to the overcurrent protection or the opening of the winding due to the short circuit, the action time of the high current is very short, the heating of the winding is larger but the action time is shorter, and the overall heating effect is not very obvious.
In the inspection process of winding short-circuit fault, it can be found that serious faults between turns, ground and phase will lead to local explosion of windings, and small bead particles produced by melting of winding conductors due to high temperature, and aging insulation pollution to almost the entire cavity of the electric motor.
From the analysis of the impact of the fault on the motor, the reliability of the electrical part should be the focus of any electric motor manufacturer.
If you want to get more information, please contact with Dongchun motor , a professional electric motor manufacturer in China .
