Surge short circuit is not an unfamiliar word to motor producers and users, and it is also one of the main causes of motor failure. What does surge short circuit mean, how is it caused, and what are the specific manifestations?
A surge short circuit refers to the short circuit between coil winding turns of the same phase. It is a short circuit fault between the same phase coils of the stator end winding due to electromagnetic frequency multiplication vibration, which causes the insulation wear of the coil.
The formation of a surge short circuit may be during the production process of the motor, or after the motor has been assembled and operated for a long time.
一、Suege short circuit in the motor production process: In the previous article " What causes surge failure", 6 articles about the motor production process are briefly described. The common causes of failure, the first of which is about how the surge short circuit is caused, the possible reasons, and how to correct it, this article will not explain it in detail.
二、Surge short circuit after the motor is assembled and running: Sometimes I see an electrical appliance fire event in a certain place in the news. Most of the culprits are the motor, which is manifested as overheating of the motor. Surge short circuit, because the continuous vibration of the motor during operation displaces the previously hidden short-circuit point. When the two short-circuit points of the coil touch or the short-circuit point of the winding contacts with the silicon steel sheet, the short-circuit between turns is prone to occur.
When there is a short circuit between turns, there are mainly the following five manifestations:
1. The temperature of the motor is too high when it is working, and it works in an abnormal state, and the insulation layer of the motor is burned, resulting in a short circuit between turns;
2. The three-phase current is unbalanced, the torque of the motor decreases, and the motor generates heat and short circuit;
3. There will be noise when the motor is short-circuited, the noise is dull and accompanied by a burnt smell;
4. The enameled wire is scratched during the production process of the motor, which leads to the reduction of surge insulation and short circuit phenomenon;
5. The motor is overloaded for a long time, making the insulation age and losing its insulation effect.
Surge short circuit is very harmful. How to identify it requires a professional surge tester. About the principle of surge tester, the editor’s previous article also introduced it, you can click to view it and kill the possible danger in the cradle.
This article was originally written by AIP, which focuses on global motor testing, all rights reserved, infringement must be investigated, please indicate the source for reprinting.