In the structural design, the main consideration is also the influence of non-sinusoidal power characteristics on the insulation structure, vibration, and noise cooling modes of the variable frequency motor. Generally, the following issues should be considered:
1, Insulation grade, generally F grade or higher, to strengthen the insulation of the ground insulation and wire insulation, in particular the ability to withstand the impact of insulation voltage.
2. For the vibration and noise problems of the motor, fully consider the rigidity of the motor components and the whole, try its best to increase the natural frequency so as to avoid resonance with each secondary wave.
3. Cooling method: forced air cooling is generally used, that is, the main motor cooling fan is driven by DuLi motor.
4, to prevent shaft current measures, the capacity of more than 160KW motor should use bearing insulation measures, mainly easy to produce magnetic circuit asymmetry, will also produce shaft current, when the current generated by other high-frequency components combined with the role, the shaft current will Large increase, resulting in bearing damage, so generally take insulation measures.
5, For constant power variable frequency motors, when the speed exceeds 3000/min, a special high temperature resistant grease should be used to compensate for the temperature rise of the bearing.