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U.S. Department of Energy
Office of Scientific and Technical Information

Temporary operation of motors with cut-out coils. Final report

Technical Report ·
OSTI ID:5571499
A project was undertaken to evaluate the performance of auxiliary power plant induction motors which have suffered stator winding failures and have then been restored to temporary service by cutting out and by-passing the failed coils. Both the circulating current within a multi-circuit phase and the changes in phase current as a result of coil cutouts were analyzed in terms of motor impedance parameters. Cooperative effort with a major utility indicated, however, that precise parameter and stator winding data would not usually be on file for the failed auxiliary motor. Therefore it was decided to present numerical results in this report based on a set of per unit values of motor impedances which are believed to be representative of typical power station auxiliary induction motors now in service. Calculation procedures are provided to permit quick estimates of motor current and temperature when the motor is operating with coils or complete circuits cut out. Examples are included to illustrate the use of the calculation procedures for various types of stator winding failures. In addition, recommendations are given for improving thermal or mechanical performance in certain cases.
Research Organization:
Technology Assessment Group, Inc., Schenectady, NY (USA)
OSTI ID:
5571499
Report Number(s):
EPRI-EL-4059; ON: TI85920713
Country of Publication:
United States
Language:
English