Kirk Kirkland
Electrical Repair Service Co. 
Birmingham, Alabama
Technical Education Committee Member

Editor's Note: This article is similar to a July 2006 Currents article titled "Tips for Test Running Motors With Roller Bearings." These two articles complement and supplement each other.

End users frequently demand that EASA service centers provide an array of test data at the conclusion of the service/repair process. These tests are normally to validate compliance with the customer’s motor repair specifications. It is also a good idea to have your own in-house specifications so you can prove that you’re compliant with EASA motor repair guidelines such as those found in the Recommended Practice for the Repair of Rotating Electrical Apparatus (ANSI/ EASA AR100-2006).

One of the more common tests involves running the motor no-load and providing the motor owner with electrical test information and vibration spectrums covering various frequency bands. No-load run tests are commonly applied to AC induction motors. In many cases, these motor types are designed for a belted-duty application. That means they may have a roller bearing in the drive end of the motor. The most common roller bearings utilized in belted applications are the two-piece NU type that consists of an inner race mounted on the bearing shaft journal and the rollers caged on the outer race.

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