Test & Measurement

Tip of the Week: Motor Overcycling

June 19, 2017

Restarting a motor too many times within a short timeframe can permanently damage it.

Restart a motor too many times within a given period (say, 30 minutes), and you can permanently damage it. The reason is excess heat. Because of inrush current, each start of a motor generates far more heat than when the motor is running. While the motor is running, it cools down from the temporary “high temperature” condition that starting produces.

Ecmweb Com Sites Ecmweb com Files Uploads 2017 06 14 Thinkstock Photos 498891046 Motor

Temperature monitoring on a motor is excellent for maintenance purposes, because (for example) you can see whether the motor is trending hot and thus know something is wrong. But temperature is an inherently slow process variable; there is always a lag, so you never know for sure exactly how hot things are just by looking at a temperature gauge.

You can find general restart guidelines by contacting the manufacturer of the motor. Modify those based on actual conditions, such as poor air circulation or high ambient temperature.

About the Author

Mark Lamendola

Mark is an expert in maintenance management, having racked up an impressive track record during his time working in the field. He also has extensive knowledge of, and practical expertise with, the National Electrical Code (NEC). Through his consulting business, he provides articles and training materials on electrical topics, specializing in making difficult subjects easy to understand and focusing on the practical aspects of electrical work.

Prior to starting his own business, Mark served as the Technical Editor on EC&M for six years, worked three years in nuclear maintenance, six years as a contract project engineer/project manager, three years as a systems engineer, and three years in plant maintenance management.

Mark earned an AAS degree from Rock Valley College, a BSEET from Columbia Pacific University, and an MBA from Lake Erie College. He’s also completed several related certifications over the years and even was formerly licensed as a Master Electrician. He is a Senior Member of the IEEE and past Chairman of the Kansas City Chapters of both the IEEE and the IEEE Computer Society. Mark also served as the program director for, a board member of, and webmaster of, the Midwest Chapter of the 7x24 Exchange. He has also held memberships with the following organizations: NETA, NFPA, International Association of Webmasters, and Institute of Certified Professional Managers.