Following your repair procedure, you found your motor runs far too hot. In Part 1, we identified two external factors that may be causing this. Here are three more factors that could be causing you trouble.
• Contaminants. Windings that are coated with dirt or grease are actually coated with a thermal insulation layer. Use an approved method for cleaning the windings in situ. To find out what methods are approved, contact the motor manufacturer. An incorrect method may destroy the motor.
• Particles. In a paper processing operation, a non-enclosed motor was presumably protected by a sheet metal barrier between it and paper particles that were tossed up by process equipment. But operators tracked paper bits all over the place, and over time such particles found their way into the windings and accumulated there, causing motor overheating. Look at your processes for something similar.
• Mechanical overload. A common example is a scrap grinder that has been abused or that is in long need of a blade replacement. Another example is a viscosity change in the liquid being stirred in a vessel or pumped out of it
