Insulation Health: The Key to Transformer Longevity

The most common cause of isolation transformer failure is insulation breakdown. Over time, heat, moisture, and electrical stress can degrade the varnish and paper that keep the windings separate. At VoltApex, we recommend a semi-annual Insulation Resistance (IR) test using a Megger. This 1500-word guide walks you through the testing procedure and what the numbers mean for your facility's safety.

Interpreting Megger Values

When testing between the primary and secondary windings, you should ideally see values in the Giga-ohm range. If these values start to drop into the Mega-ohm range, it indicates that moisture has entered the unit or the insulation is aging. We provide tips on 'drying out' a transformer and when it's time to consider a professional re-varnishing or replacement from the VoltApex service team.