Electricity Today T&D Magazine

Since over 80% of electrical maintenance testing involves evaluating insulation integrity, the first and most important test done on electrical equipment is an Insulation Resistance (Meg) Test. This is because electrical insulation begins to age as soon as it’s manufactured and aging causes deterioration in the performance of the insulation. Harsh operating environments will also cause further deterioration, especially where the electrical insulation is exposed to extreme operating temperatures, moisture, and chemical contamination. As a result, personnel safety and operating reliability can both be compromised. It’s extremely critical to always know the electrical condition (IR) of the insulation in your equipment at all times.
For decades, plant personnel have had to perform periodic insulation resistance tests with handheld megohmmeters to prevent motor failures that lead to costly unplanned shutdowns, penalties and expensive re-winding repairs.
However, these tests only provide a “snapshot” of the motor’s health. In a matter of only...