1001gece/iStock/Getty Images Plus
Ecmweb 26129 Ecm Mro Quiz
Ecmweb 26129 Ecm Mro Quiz
Ecmweb 26129 Ecm Mro Quiz
Ecmweb 26129 Ecm Mro Quiz
Ecmweb 26129 Ecm Mro Quiz

Electrical Troubleshooting Quiz — Nov. 5, 2019

Nov. 5, 2019
Solving for motors that show signs of heat-related winding damage

An important production line has been in the plant for about five years. During its first few months, there were several motor failures due to overheating.

To solve this recurring problem, the plant engineer had heat shields installed between the motors and the hot process. He designed a cooling system consisting of a shroud with ducted air. He explained it as being like a home roof venting system. Cool air gets drawn in through soffit vents as warm air flows out through the roof vents.

But recently, the motor failure problem started again, and the motors show signs of heat-related winding damage. That plant engineer is gone, but his shroud looks good. How would you solve this problem?

Possibly, the vent system of the shroud is clogged and/or the heat shield has deteriorated. Before checking either, conduct an “As Found” thermographic survey. Remove the shroud and clean the exposed area and the shroud as needed. Before removing the heat shield, conduct a thermographic survey. Remove the heat shield, and conduct another thermographic survey and compare to the previous one. Replace the heat shield if indicated.

Put the system back together, wait a day, and conduct another thermographic survey. If results are not greatly superior to the As Found, find a source of cool air; use an intake fan to supply the shroud with it.

Next, check for voltage imbalance. If it's more than 2%, address that issue; for example, put this system on its own transformer/panel. Measure power factor at each motor, add capacitors at each motor as needed.

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.

Voice your opinion!

To join the conversation, and become an exclusive member of EC&M, create an account today!

Sponsored Recommendations

Electrical Conduit Comparison Chart

CHAMPION FIBERGLASS electrical conduit is a lightweight, durable option that provides lasting savings when compared to other materials. Compare electrical conduit types including...

Fiberglass Electrical Conduit Chemical Resistance Chart

This information is provided solely as a guide since it is impossible to anticipate all individual site conditions. For specific applications which are not covered in this guide...

Considerations for Direct Burial Conduit

Installation type plays a key role in the type of conduit selected for electrical systems in industrial construction projects. Above ground, below ground, direct buried, encased...

How to Calculate Labor Costs

Most important to accurately estimating labor costs is knowing the approximate hours required for project completion. Learn how to calculate electrical labor cost.