1. A New Method for the Accurate Prediction of On-Load Power Factor in Two-Pole Induction Motors Considering Shaft Eddy Currents
- Author
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Alberto Tessarolo, Matteo Olivo, F. Luise, Mauro Bortolozzi, Olivo, Matteo, Bortolozzi, Mauro, Tessarolo, Alberto, and Luise, Fabio
- Subjects
electric machines ,Design ,Rotor (electric) ,Computer science ,Energy Engineering and Power Technology ,finite element analysis ,Power factor ,power factor ,AC power ,Magnetic flux ,Finite element method ,electric machine ,finite element analysi ,induction motor ,law.invention ,Control theory ,law ,induction motors ,Eddy current ,shaft currents ,Electrical and Electronic Engineering ,Induction motor ,Slip (vehicle dynamics) - Abstract
An accurate prediction of medium-voltage induction motor (IM) power factor in rated conditions is important in the design stage to verify the machine compliance with specifications according to international testing standards. Laboratory and industrial experiences suggest that significant errors in full-load power factor calculation can result for two-pole IMs in particular, due to the eddy currents induced in the solid-steel shaft at rated slip. Such eddy currents are responsible for rejecting the main flux into rotor laminated yokes causing an increase in their saturation and, hence, in the required magnetizing current with respect to no-load conditions. This article proposes a method to study the phenomenon through a combination of analytical and simplified Finite Element (FE) calculations as a computationally-efficient alternative to conventional FE simulations. The results of the proposed approach are experimentally assessed by comparison with measurements on a set of built and tested medium-voltage two-pole IMs of different sizes, showing very good accuracy and computational performance.
- Published
- 2020