New Concepts in Large AC Motor Protection - Ensure electric motors continue to operate when exposed to all foreseeable electrical, mechanical, and thermal disturbances

摘要

Thanks to ongoing innovations in technology, electrical engineers' approach to motor protection has changed over the years. The traditional strategy to large AC motor protection (e.g., over 500 hp), used since the early 1900s, has been to use electromechanical relays that responded to motor current, voltage, and temperature so as to provide alarms and/or trip the motor offline. In this arrangement, the starter equipment is usually combined with the motor protection (typical panel is shown in the Photo). A new method, developed in the mid-1990s, is to use a microprocessor-based motor management relay, which responds to the. same signal in a more intelligent manner.