Low Voltage Testing Demonstrations

For many years I have been asked about the use of low voltage testing for troubleshooting medium and high voltage electric motors.  I utilize both high and low voltage technologies when evaluating the condition of electric motor insulation systems of all sizes.  Usually both technologies will detect problems with windings.  However, there are those 10% of windings evaluated that will be missed either by high voltage testing (ie: insulation resistance/high potential testing, surge testing) or low voltage testing (ie: MCA in the form of either ALL-TEST Pro or PdMA).  I am a supporter of the use of all technologies that will assist the technician or engineer in the detection and troubleshooting of a problem.

In the linked video I am demonstrating the use of the ALL-TEST Pro as compared to a high-end hand-held LCR meter.  This was a discussion that had come up in a standards working group – the comparison of the type of meter.

It is important also to remember that different types of instruments are meant to be applied to different types of applications.  Low voltage testers of different types use different types of outputs based upon the type of devices they are testing.  For instance, the LCR meter in use was specifically identified by the manufacturer that it was not designed, nor was capable of, troubleshooting an electric motor.  Yet, some individuals felt that they knew better.  Also, the ALL-TEST IV PRO in use in the video IS designed to be used on electric motors.  I did not have a PdMA available to perform testing as well, but have had enough experience with the instrument to know that the results would be similar.

This was demonstrated by a Large Electric Motor User Group (LEMUG) study on testing medium voltage motors by the Electric Power Research Institute (EPRI) and is available for download from their website.

Enjoy the demonstrations!


Leave a Reply