Key points are not available for this paper at this time.
Electric Motors--J. Kirtley.Terminoloy and Definitions--N. Ghai.Fundamentals of Electromagnetic Forces and Loss Mechanisms--J. Kirtley.Induction Motors--J. Kirtley and N. Ghai.Synchronous Motors--J. Kirtley and N. Ghai.Permanent Magnet-Synchronous (Brushless) Motors--J. Kirtley.nDirect Current Motors--J. Kirtley and N. Ghai. Other Types of Electric Motors and Related Apparatus--J. Kirtley.Motor Noise and Product Sound--R. Lyon.Servomechanical Power-Electronic Motor Drives--S. Leeb.
A 1988 study studied this question.