Electrical machines: Keep your eyes open

Electrical testing will miss quality defects.
Photo: Adobe Stock

We seem to rely heavily upon testing technologies and results to prove or disprove the reliability of equipment, says Howard Penrose of MotorDoc LLC. He cited this as a concern in the 1990s with the arrival of new technologies with technicians and engineers becoming more reliant on testing only.

He says many people do not realize most of the standards covering electric machines emphasize visual inspections. For instance, electrical testing of a random wound motor will identify flaws and degradation – to a point – in an insulation system. However, it will usually miss quality defects, such as crossed turns, which result in significant electrical potential between conductors, or moveable conductors. Also, in both large and small machines, testing may not always detect contamination.

New testing and methods do provide more insight into the condition of equipment, as well as advances in understanding of the data collected, but visual inspections can provide greater insight into potential problems.

Source: MotorDoc LLC newsletter

This article originally appeared in the October 2018 print issue of PLANT Magazine.