Handbook of Electrical Engineering

INDUCTION MOTORS 129

5.10.5 Part winding method

A special design of motor is used. The stator has two three-phase windings that are arranged in
parallel and wound in the same slots. If the two windings are the same then on starting and during
run-up one winding would provide half of the total torque at any speed. Hence one winding is used
for starting and both for running. The method is not suited to small or high speed motors. With two
equal windings the starting current and torque are half of their totals. This method is seldom used
in the oil industry because of the preference for standard motors, and the availability of satisfactory
alternative methods.

References

1. M. G. Say,The performance and design of alternating current machines. Sir Isaac Pitman and Sons Ltd
   (1963).


2. A. E. Fitzgerald and C. Kingsley,Electric machinery. The dynamics and statics of electromechanical con-
   version. McGraw-Hill Book Company, Inc. (1961).


3. H. Cotton,Advanced electrical technology. Sir Isaac Pitman and Sons Ltd (1967).


4. D. O’Kelly and S. Simmons,Introduction to generalized electrical machine theory. McGraw-Hill Publishing
   Company Ltd (1968).


5. W. Shepherd and L. N. Hulley,Power electronics and motor control. Cambridge University Press (1987).
   ISBN 0 521-32155-7


6. S. B. Dewan, G. R. Slemon and A. Straughen,Power semiconductor drives. John Wiley & Sons, Inc. (1984).
   ISBN 0 471-62900-6


7. David Finney,Variable frequency ac motor drive systems. Peter Peregrinus Ltd (1991). ISBN 0 863-41114-
   2


8. M. W. Earley, J. V. Sheehan and J. M. Caloggero,National electric code 1999 handbook. National Fire
   Protection Association, USA. Eighth edition. ISBN 0 877-65437-9
   9.Requirements for electrical installations (BS 7671:1992). IEE Wiring Regulations, 1997. Sixteenth Edition
   plus amendments. ISBN 0 852-96927-9


9. J. Hindmarsh,Electrical machines. Pergamon Press (1968) Library of Congress Card No. 63–22494.


10. Alexander S. Levens,NomographsJohn Wiley & Sons, Inc. (1948 and 1959). Library of Congress Card
    No. 59–11819


11. S. Brodetsky,A first course in nomography. G.Bell and Sons Ltd. (reprinted 1938).