Driving Force Blog - December 2022

Written by Patrick Malloy, Nidec Motor Corporation Technical Trainer

One of the biggest threats to a motor is a dirty environment. TEFC, or Totally Enclosed, Fan-Cooled motors, are fully sealed to keep contaminants out but it’s still important to keep them free of dust, dirt, oil, and debris. TEFC motors vent heat through their external fins and the fan, so simply stated, “if it ain’t clean, it ain’t cool”. When the motor is dirty, the ability for it to dissipate heat is reduced leading to internal damage. Additionally, excess wear and tear can occur if a motor cannot stay cool – causing it to die early. As a good rule of thumb, for every 10°C above the insulation that the motor rated for, the life of the internal winding insulation is cut in half.

On the other hand, there are also Open Drip Proof motors which have open vents allowing air to flow directly over the windings, keeping the motor cooler and preventing overheating. However, the open concept of this motor allows for outside contaminants and dust to enter the chamber easily. This can cause extreme damage, especially in a dusty or dirty environment.

Preventative maintenance and cleaning of motors and components should be done on a routine schedule and should always be completed before and after operation, especially in dirty environments and before the motor is due to be put away for the season. Here are some helpful general motor winterization tips as we are approaching frosty weather.

1. Dust them off 
   
   The exterior of motors, vents and screens need to be cleaned regularly. One method of doing this is to blow out dirt from all areas of the motor with no more than 50 pounds of dry, compressed air.
   
   
2. Schedule Regular Examinations for Electrical Components
   
   Regardless of environment, all electrical components should be regularly inspected and maintained to help identify loose or dirty connections.
   
   
3. Check for Loose Components
   
   Components can become loose over time and cause unexpected or excessive wear. Check fittings, mounts, mounting bolts, steel base plates, and other components regularly to ensure that they are secure and in good repair. Also check for loose pins, bolts, or bearings.
   
   
4. Check the Belts and Pulleys
   
   Inspection of belt-driven applications is extremely important, a belt failure could lead to equipment damage, injury to personnel, or even death. Regularly inspect belts for wear and tension. It is equally important to verify that the pulley or sheaves are not worn and are within tolerance.
   
   
5. Schedule Annual Vibration Analysis Tests
   
   Excessive vibration can significantly shorten the lifespan of your electric motor and driven equipment. The biggest culprit for damage is the way the vibration creates wear on metal parts and can cause bearings and windings to fail.
   
   Excessive vibration is most commonly a mechanical issue but can also be electrical; mechanical causes are more common. When looking for the cause of mechanical vibration examine belts for proper tension, check for faulty bearings, or misaligned or imbalanced components such as pulleys, shafts and possibly the rotor.

Issues to look for:

For more information and training on belt driven equipment, vibration testing, and other motor topics direct your customer to the U.S. MOTORS® University training site. There are training modules and videos on these subjects and many more available on the U.S. MOTORS University site.

Bio: Patrick Malloy, Technical Trainer at Nidec Motor Corporation, manages, runs, and creates content for our U.S. MOTORS University technical training courses. With over 25 years of training experience in manufacturing, safety, and motors theory, Patrick has developed more than 68 training modules for employees and customers.