The Study of Harmonic Behavior Caused by Slotting for Speed Calculating Application in Induction Motors

Abstract

In this paper, the study of harmonic behavior caused by slotting (slot harmonics or rotor slot harmonic,RSH) for speed calculating application in induction motor is proposed. These RSHûs are dependent from motorspeed and inherent in stator currents. The stator current data are processed digitally for fully analysis and studybefore implementation. The RSH behavior is tested under steady state conditions with the specific conditionsuch as: sinusoidal and PWM inverter supplies, unbalance voltage condition, temperature etc. The results undersuch conditions show that harmonic signals are within the RSH range. From the experimental results, the errorfor speed calculation is under 0.1% if RSHûs exist in pairs.