Influence of stator slot/pole number combinations on the rotor bar current waveform and performance

What is it about?

Even if the winding layout is the same, the stator slot/pole number combination has a considerable effect on the distortion level of the bar current and the electromagnetic performance, including torque, torque ripple, power factor, and efficiency.

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Why is it important?

The accurate prediction of rotor bar current in induction machines (IMs) is essential in terms of accurate prediction of torque, torque ripple, rotor bar copper loss, iron loss, and efficiency. Since the IMs were first built, it has been assumed that the rotor bar currents are sinusoidal under the 3-phase balanced sinusoidal source and healthy operation conditions. However, in the recent studies it has been revealed that the bar currents can be non-sinusoidal under very high speed operation close to synchronous speed, or fairly high electrical loading operation conditions, or in the IMs whose air-gap length is considerably small.