Megger Question

It is a code.Each letter and number has explanation.

5 at 1st digit = operated

5 at 2nd digit = by

3 at 3rd digit = Useless

V at 4th digit = fellow

so now you know what is 553V.

for 480V winding, apply only 500V. When u apply 1000V, as the clearance from phase to body is less and so the leakge current will be more. So the equipment itself cant inject 1000V and reading is less like 0.5Mohms. acc to my experience from my field services, we follow the below.

< 1000V - - Apply 500V
1000-2500V - Apply 500 - 1000V
2501-5000 - Apply 1000-2500V
5001-12000 - - Apply 2500-5000V
>12000 - - Apply 5000-10000

Hope it helps!

-Vijay