High-Inertia Drive Motors and Their Starting Characteristics

The motor for a large reactor coolant pump failed while starting. The motor-application and the motor-failure are discussed in detail. A review of applications of motors for high-inertia drives shows that a motor designed and built to today´s industry-standards might be overstressed while experiencing abnormal starting conditions, even though its protection is in accord with accepted practice. The inter-relationship between motor characteristics and characteristics of various types of protection are discussed, briefly. Such protection is also discussed in a companion paper. [1] The review concludes that motor specifications and motor standards should be augmented.