As any service technician knows from experience, contamination is one of the leading causes of premature motor failure.
The biggest challenge, from a service standpoint, is that motors typically spend their working lives unseen, either covered or installed in an enclosed area, such as inside a furnace. A lot of mischief can take place away from watchful eyes, and the knowledgeable service technician must be prepared to go beyond treating the most obvious cause of motor problems.
For example, materials such as lint, sawdust, and other contaminants can build up on the motorís frame and reduce heat dissipation. These insulating materials often are attracted by the frameís surface coating or by lubricating oil used in the application.
The vent slots in the frame are easily clogged, cutting down the amount of cooling air that flows over the motor. Even a relatively thin layer of dirt can decrease the motorís ability to dissipate heat, and as little as a 1 to 2 degree F rise in motor temperature can accelerate the problem.
Many inexperienced service technicians, however, limit their cleanup to just the motor itself. Thatís good, but it still represents treating just half of the patientís symptoms.
Use clear water to remove any accumulated salts from the motor, the shaft, and the surrounding enclosure. For more corroded areas, a wire brush and commercially available cleansers will do the job.
Always check to make sure brackets and metal enclosures are still sound and havenít been compromised by corrosion. If you suspect any problem, replace the component.
When cleaning the motor itself, pay particular attention to the ventilation openings. A toothbrush or similar soft brush works well in keeping these important openings free of dirt and debris.
The next big factor is chemical contamination. Many motors work in environments where they are subjected to caustic or corrosive chemicals. These include swimming pools, air conditioning equipment, gate openers, and others.
Salts are the major culprits, followed by water chlorinating compounds, acids dissolved in rain water, cleaners and degreasers, and many others. These insidious materials override the motorís defenses by contaminating the anticorrosive materials applied to the motorís frame, shaft, and windings.
Look For More
As you are cleaning the motor, look at its surrounding environs.
ē Are dust, dirt, or other types of buildup inside the enclosure?
ē What about the condition of the belt, if itís a belt-driven application?
ē Wheels, gears, brackets ó each of these can accumulate contaminants that can resettle on the motor once it gets back to work.
In short, as long as youíre cleaning, itís good practice to police the entire area around the motor.
Keeping a motor clean and cool is an important part of the HVACR service process, but itís equally important to pay attention to the many components surrounding the motor. Maintain a clean working environment and youíll be rewarded with longer motor service life, fewer emergency replacements, and happier customers.