Polarization Index testing or PI testing is often misunderstood and misapplied. it’s a highly useful test to determine the health of motor insulation and in so doing, identify accumulations of contaminants and assess the physical health of the insulation. In short, polarization means to cause something to obtain polarity and this test causes molecules to move toward a given pole in the motor.
In the motor shop, we apply a positive charge to the motor conductors and a negative charge to the motor frame. This video highlights the testing procedure, changes over time that have altered those procedures, why you should use PI testing with other test methods, and how to think about your PI test results.
To read the complete story on PI testing best practices be sure to look at the original article. Or read David L. McKinnon’s excellent paper on the benefits of the graphical PI test, which EECO recommends, PdMA graphical PI profile. And take a few minutes to see for yourself how and why updated PI testing procedures are the best way to test insulation status in your motors.
PI testing video explains things you should do
In the past, PI testing was all about taking a standard insulation resistance test at 60 second and again at 10 minutes. It was an accepted fact that the 10 minute value should exceed the 1 minute value by a factor of two, or more. IEEE recognized that changes motor insulation required a more in depth test. Here are four tips that will improve the quality of your PI tests, whether they are performed in the field, or in the motor shop. The video will help you understand the following.
- Why PI tests require much more interpretation.
- Learn why PI tests are not good stand alone acceptance tests
- Why is graphical recording of the PI more helpful
- What other tests should be used in conjunction with PI tests.
To get started with a testing program, or just learn more about PI testing, call us at 800.993.3326. Or email the motor team at email@example.com