Torsional Coordination of High Speed Synchronous Motors-Part II

The increasingly frequent use of larger four-pole and six-pole synchronous motors to drive high speed equipment, such as compressors, has focused much attention on coordination of the motor and driven equipment system. A relatively straight forward analytical method of calculating the motor-developed air-gap torque from the d and q axis equivalent circuits is presented. The problem of relating air-gap torque to shaft torque is discussed briefly, and methods of experimentally determining both quantities are presented. A method of assessing the capability of a shaft section to withstand a given torsional duty is also presented.