Ecmweb 8240 Electricmotorthermalimagemrepngcropdisplay1
Ecmweb 8240 Electricmotorthermalimagemrepngcropdisplay1
Ecmweb 8240 Electricmotorthermalimagemrepngcropdisplay1
Ecmweb 8240 Electricmotorthermalimagemrepngcropdisplay1
Ecmweb 8240 Electricmotorthermalimagemrepngcropdisplay1

Tip of the Week: Cool Runnings

April 4, 2016
Thermographers provide the data that help you solve motor heating problems most effectively

In our previous article, we looked at the "why" for ventilating motors and saw that thermal imaging lets you avoid guesswork. Now let's look more closely at the "how" part of the plan.

Let’s suppose you’ve replaced the main motor of a process machine several times. Let’s say it’s a hot process (e.g., extrusion of some sort). This means there are sources of heat all around the motor. You know the motor failures were heat-related, partly because it’s so darn hot where that motor sits and partly because the motor repair shop examined a couple of these and reported definite signs of overheating.

Your plant has been very good at “saving money,” so instead of owning a thermographic camera, your maintenance department owns a few contact thermometers.

The motor is situated with one side of the housing facing the aisle and most of its body tucked into the machine. You took readings around the motor and verified that it’s about 150°F in the air on the machine side of the motor and about 120°F on the aisle side. The motor itself is blocking airflow to where cooling air is most needed. A pocket of hot air behind it is keeping the motor from dissipating enough heat.

To solve this problem, you route flexible metal ductwork to the machine side of the motor the next time the machine is down for servicing. The plant manager congratulates you on how neat it looks, all tucked in there and nicely secured.

After the machine has run for a while, you go back out there with your trusty (but cheap) thermometers and see you’ve dropped that machine side temperature to about 145°F. How can this be?

Let’s change the scenario a bit. Your plant has been very good at reducing costs by investing in the test equipment needed for maintenance. Your only problem in this case is deciding which of your thermographic cameras to use.

Your Level II thermographer performs a thermographic survey all around that machine and then presents you with a series of composite heat maps. From these, you decide the best routing for that cooling duct. And that’s really good, because it means you’re going to avoid running that duct over a set of cooling fins that would heat up the “cool” supply air.

The plant manager looks through the thermographic camera and sees the machine side temperature of the motor is about 80°F. He asks if you can duct supply air to the front, as well.

Avoiding heat sources when ducting in cooling air is just an example of how you can use thermography to figure out the “how” when solving a motor heating problem.

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.