IEEE 429-1994

This recommended practice outlines a test procedure for comparing two or more sealed insulation systems in accordance with their expected life at rated temperature. The procedure is limited to insulation systems for ac electrical machines using form-wound preinsulated stator coils rated 6900 V and below. The intent of this test procedure is to evaluate insulation systems for use with air cooling under severe environmental conditions, where the insulation is exposed to conducting contaminants. This procedure does not cover special requirements, such as those for machines enclosed in gas atmospheres or machines subjected to strong chemicals or submersion in liquid, etc. The procedure includes instructions for testing candidate systems in comparison with known systems having a proven record of service experience and interpreting the results of these tests.

The purpose of this procedure is to classify sealed insulation systems for the machinery used in severe environmental conditions (and falling within the scope of this recommended practice) in accordance with their temperature capabilities by test, rather than by chemical composition. Data from such tests may be used to establish the temperature classification of new insulation systems before they are service-proven. In order to provide data from which a base of reference for temperature classification can be established, service-proven sealed systems should also be tested according to this test procedure.

Revision Standard - Inactive-Withdrawn. A test procedure for comparing two or more sealed insulation systems in accordance with their expected life at rated temperature is outlined. The procedure is limited to insulation systems for alternating-current (ac) electrical machines using form-wound preinsulated stator coils rated 6900 V and below.