The purpose of this article is to review the Fluke-1587FC on how to use and understand the purpose of the DAR and PI testing function.
The Fluke-1587FC has a straightforward Insulation Test function as well as two other functions called the Polarization Index Test (PI) and Dielectric Absorption Ratio Test (DAR).
The (DAR) test is an overall 1-minute test and compares two readings one at the 30-second point and the other at the 60-second point and the results are a ratio between the two measurements.
The (PI) test is an overall 10-minute test and compares two readings one at the 1-minute point and the other at the 10-minute point and the results are a ratio between the two measurements.
Below is a table showing anywhere between Dangerous to Excellent results. The 60/30 Second Ratio is the DAR Test and the10/1 Minute Ratio is the PI Test.
If the results are a higher number than 1.6 for the (DAR) test or higher than 4 for the (PI) test the Fluke-1587FC will show ERR. Granted normally ERR results would indicate something is wrong but in this case it’s Excellent.