I'm going to buy a new megger and am wondering which one is best for my application. I notice that they have several different voltage ratings available. The majority of the time it will be used for insulation testing on 480v motors. I also prefer analog over digital. Can anyone help me understand which voltage rating would be best for my application.
Helectric, I currently use the AVO Megger BM223. It gives 3 ranges of Insulation testing and one of Continuity. This meter has both an analouge and digital display. It also has a Null feature for nulling out your test leads when doing resistance checks over long distances, such as when doing tests on the resistance of conductors back to the panel, from a fitting. The BM223 is really only a dual use sort of instrument, as in sure it is good at Continuity testing and it is good as an Insulation Resistance tester, that may fit your bill. But if I had the ultimate in testers, I would go with one of the Kyoritsu multi-testers. I used one of these at an EC company I used to work for. Things like RCD tester, Loop tester, Insulation Resistance, Earth Electrode Resistance and also a Phase sequence tester, makes these units value for money. You can also download to a PC all of your test results and print them out with a USB interface. Haven't we come so far guys!.
I do not know what the testing pocedure is in the States but here in the UK Insulation tests are required to be carried out at double the running voltage. So 240v systems are meggerd at 500v, and 415v at 1000v
As for digital / analouge meters I prefer to teach using analouge (but cant get new ones) just becouse they are easier to understand. But use a digital away from the school