In the fault cases of 3 phase electric ac motor products, the stator part’s the problem is mostly concentrated in the winding. The rotor part’s problem is more focused on mechanical performance. For the wound rotor, of course, also includes the winding fault problem.

Compared with the wound rotor motor, the chance of casting aluminum rotor problems is much less, but once there is a problem, it is a more serious problem.

First, under the premise of no over-speed protection, the wound rotor is more prone to the problem of packing, which is the end of the rotor winding’s serious radial deformation, which is very likely to interfere with the end of the stator winding, resulting in the whole ac motor asynchronous winding burning and mechanical stuck. Therefore, the speed of the winding rotor motor can not be too high, and the synchronous speed is generally 1500 RPM and below.

Second, the cast aluminum rotor has local or overall heating problems. If there is no problem with the design, it is more because the casting aluminum process is not good for the design, the rotor has a serious problem of broken or thin strips, the motor is running when there is local or even large area heating, the rotor surface is blue when serious, and the flow aluminum problem is more serious.

Third, for most of the cast aluminum rotor, the end is relatively stable, but if the design is not reasonable, or there is a large current density, high temperature rise, the rotor end may also appear similar to the winding rotor spinning problem, that is, the end of the wind blade serious radial deformation, the problem is more than 2 pole motor, of course, its casting aluminum process is directly related. Another serious problem is that aluminum is melted directly, either in the rotor slot or in the rotor end ring.

Objectively speaking, when this problem occurs, it should be analyzed from the design level, and then the casting aluminum process is comprehensively evaluated. Compared with the stator part, due to the particularity of the rotor in motion state, it should be evaluated from the mechanical and electrical aspects, and the necessary performance verification.