The first time you pick up a megohmmeter, it looks familiar but behaves differently. It has probes and a display like a multimeter, but the numbers it produces are completely different. Why is 500 MΩ good on some equipment and 5 MΩ good on others? Why does the reading keep climbing after you apply voltage? Why does pressing… Read More »
You test a motor at 20°C and read 200 MΩ. Looks good. You test the same motor three months later at 45°C and read 40 MΩ. Has the insulation degraded? Or is it just the temperature? Without correction, you can’t tell. A 200 MΩ reading at 20°C and a 40 MΩ reading at 45°C can represent exactly the… Read More »
You ran the megger test. You have a number on the screen. Now what? This is where most guides leave you hanging. They tell you “higher is better” and move on. But in the real world, you need to know whether that reading means the equipment is safe to run, needs monitoring, or should be taken out of… Read More »
Megger testing is the fastest way to find out if your motor’s insulation is healthy or heading toward failure. The test takes about 5 minutes once you’re set up, and it can save you from a $50,000 motor rewind or worse — an unplanned shutdown. In this guide, I’ll walk you through exactly how to megger a motor,… Read More »