Turn Insulation Capability of Large AC Motors Part 3 - Insulation Coordination
- 1 December 1987
- journal article
- Published by Institute of Electrical and Electronics Engineers (IEEE) in IEEE Transactions on Energy Conversion
- Vol. EC-2 (4), 674-679
- https://doi.org/10.1109/tec.1987.4765908
Abstract
The coordination of the surge strength of large AC motor stator windings with the surge voltages encountered during normal switching of the motors in utility generating stations is described in this paper. The surge strength of the turn insulation of motor windings was determined from destructive tests on 17 stators [6]. The surge voltage magnitude which can strike the motor's terminals was measured on 33 motors during normal operation in several different utility generating stations [5]. The surge strength of most motors exceeds the surge magnitudes which can occur during normal service. The only motors which have a surge strength below the highest surge voltages measured were either damaged from severe aging, or had poorly made turn insulation when compared to other coils in the same stator. Vacuum switchgear does not appear to pose a greater hazard to motor windings than conventional air-magnetic breakers, as long as the vacuum circuit breaker does not interrupt motor starting currents. Improved quality control tests are required to allow manufacturers to identify the few defective coils which may occur in a winding.Keywords
This publication has 6 references indexed in Scilit:
- Turn Insulation Capability of Large AC Motors Part 2 - Impulse StrengthIEEE Transactions on Energy Conversion, 1987
- Interpretation of Megohmmeter Tests on Electrical Apparatus and CircuitsIEEE Electrical Insulation Magazine, 1986
- Investigation of Turn Insulation Failure Mechanisms in Large AC MotorsIEEE Transactions on Power Apparatus and Systems, 1984
- Improved motors for utility applications. Final reportPublished by Office of Scientific and Technical Information (OSTI) ,1982
- Statistical considerations on impulse breakdown characteristics of cross-linked polyethylene insulated cablesIEEE Transactions on Power Apparatus and Systems, 1975
- Voltage oscillations in armature windings under lightning impulses-ITransactions of the American Institute of Electrical Engineers, 1930