Synchronous Motor with Phase-Connected Damper Winding for High-Torque Loads

Considerable progress has been made in recent years in the application of low-speed synchronous motors to industrial loads requiring both high starting torque and high pull-in torque with moderate starting current demand. The problems encountered are exemplified in the drive of grinding machinery in the cement and mining industries, to which several different adaptations of synchronous motors are discussed. A form of synchronous motor with phase-connected damper winding has been devised for this type of service, developing high-torque / kv-a. ratios in a simple mechanical construction.