sanchairat/iStock/Thinkstock
Ecmweb 8189 Dirty Air Filter
Ecmweb 8189 Dirty Air Filter
Ecmweb 8189 Dirty Air Filter
Ecmweb 8189 Dirty Air Filter
Ecmweb 8189 Dirty Air Filter

Tip of the Week: Is that cooling air doing any cooling?

May 2, 2016
Keep ventilation ducts unclogged so that cool air can get inside the motor. 

Previously, we looked at the "why" for ventilating motors and saw that thermal imaging lets you avoid guesswork. We also looked more closely at the "how,” with a focus on using thermography to properly map out a correct route for cooling ducts.

Unless you’re using a totally enclosed motor, all this assumes that the cooling air can actually get inside the motor. Dirt, dust, chemicals, snow, oil, vegetation, and process waste can clog the ventilation ducts of an open-frame motor. So can insect nests, rodent nests, and associated droppings. All of this nasty stuff also may help form a thermally insulating coating on the windings.

Photo credit: sanchairat/iStock/Thinkstock

But isn’t the solution just to use a ventilation filter? You definitely should have a ventilation filter, but understand that this nasty stuff can clog the filter and therefore defeat the ventilation. This problem is quite common, partly because these filters often are installed in a way that makes inspection and replacement difficult.

The solution to a clogged ventilation filter is often to remove the filter, and that puts you back where you started — motor windings coated with nasty stuff. But at least that prevents overheating because of a clogged filter, right?

If it’s a critical motor, put a differential pressure (DP) alarm across that filter. This should trigger a local alarm light, at the very least. Preferably one that blinks annoyingly.

If it’s not a critical motor (or even if it is), you could redesign the filter system to make inspection and replacement easy. Here’s how a maintenance department at a plastic extrusion plant in Kentucky solved that issue.

A sheet metal contractor came in and built rectangular extension ducts that were attached (and sealed) to the original filter location. These extended the filter location from under the machine, where they were difficult to access.

With these in place, anyone walking by could glance at the filter and see its condition. And instead of a screw and nut assembly as the original filters had, these ducts were outfitted with hook and loop fastener strips. The filter medium was a material that these strips readily latched onto.

All of the filter openings were the same size, so that one size filter could be used plant-wide. The maintenance department ordered these precut to that size. A maintenance helper could walk through the production floor and change all the filters in less than one hour. Previously, it took two technicians that long to change a single filter.

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...

Don't Let Burn-Through Threaten Another Data Center or Utility Project

Get the No Burn-Through Elbow eGuide to learn many reasons why Champion Fiberglass elbows will enhance your data center and utility projects today.

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.