IEEE 522-2004

The purpose of this guide is to make suggestions on testing the dielectric strength of the insulation separating the various turns from each other within multiturn form-wound coils to determine the acceptability of the coils. Typical ratings of machines employing such coils normally lie within the range of 200 kW to 100 MW. Test voltage levels described herein do not evaluate the ability of the turn insulation to withstand abnormal voltage surges, as contrasted to surges associated with normal operation. These suggestions apply to: (1) Individual stator coils after manufacture (2) Coils in completely wound stators of original manufacture (3) Coils and windings for rewinds of used machinery (4) Windings of machines in service to determine their suitability for further service (preventive-maintenance testing) The repetitive voltage surges (spikes) associated with Variable Frequency Drives (VFD's) are also not addressed here. The purpose of this publication is to:(1) Define surge/impulse testing as applied to the windings of an electric machine; (2) Review the service conditions which affect or change voltage levels in a coil; (3) Recommend devices suitable for measuring surges, with precautions to avoid erroneous results; (4) Describe various points at which surge testing should be performed; (5) Present suggested surge test levels for various types of electric machines. Revision Standard - Inactive-Reserved. Revision of IEEE Std 522-1992 Suggestions are made for testing the dielectric strength of the insulation separating the various turns from each other within multiturn form-wound coils to determine their acceptability. Typical ratings of machines employing such coils normally lie within the range of 200 kW to 100 MW (270 hp to 135 000 hp). The test levels described do not evaluate the ability of the turn insulation to withstand abnormal voltage surges, only surges associated with normal operation. The suggestions apply to: (1) individual stator coils after manufacture; (2) coils in completely wound stators; (3) coils and windings for rewinds of used machinery; and (4) windings of machines in service to determine their suitability for further service (preventive-maintenance testing). Coil service conditions, test devices, and test sequence are discussed.