Hermetic motor life tests

The ultimate goal of changing part or all of a hermetic motor insulation system is to either reduce field failures, or to maintain approximately the same low level of field failures while enjoying some other benefit, such as better electromechanical performance. easier manufacture, or simply less expensive materials of construction. Assessing the effect on reliability of new materials or new designs may be a formidable task, but it is an essential one and must be considered in all phases of testing. For this reason we will review the scope of material tests and of simple system tests before describing the development of life tests suitable for hermetic motors up to seven inches in diameter. Typical life test data will also be presented.