I would love to be able to justify $1K+ for a Biddle MajorMegger, but I can't. I can justify $225 for an off-shore insulation tester, so that's what I'm looking at. On paper it seems okay.. and it's probably little different from every other off-shore battery-powered el-cheapo megger-ish object out there. I'd have to get a new set of more robust leads with good alligator clips, but other than that I'm assuming that it will be sufficient for my needs in testing perhaps one motor every two weeks on average.

<http://www.fastenal.com/web/products/detail.ex?sku=0713896>

Am I wrong? Is this the cheaply-paved road to perdition? Will I suffer an hour for every dollar saved?

Mike

Be careful. The knockoff's may not be the best option. Sometimes the do not operate as advertised.

When I worked for ALL-TEST Pro several years ago, we had a problem with Chinese knock-offs. They did not operate as they should have, providing incorrect test results. One set of knock-offs were so close that they even included our patent numbers. However, the components used were inferior.

You may want to look at some of the Fluke insulation testers and some of the other insulation testers. Another option, as mentioned in the other string, there are motor circuit analyzers that will give you winding condition in addition to insulation to ground testing. For instance, the ALL-TEST Pro 31 runs about $1500 USD and will detect cable faults, developing winding shorts and insulation to ground faults.

Howard

quote:

Originally posted by MotorDoc:
Be careful. The knockoff's may not be the best option. Sometimes the do not operate as advertised.

I don't doubt that that is true. This isn't a knockoff, however, so much as just a cheaper version. It's not meant to look like a high-end unit like a counterfeit.
This particular one has a basic accuracy in insulation testing mode of "<1000MΩ (3%rdg+5d), >1000MΩ (5%rdg+5d)", which looks reasonable to me. Accuracy isn't as important to me as repeatability, honestly, since I'm trending the data. As long as it gives me the same answer each time on a given resistance then it will work for my needs for now. I was wondering more about special features the high-end ones have that I've never heard of but might wish I had later.

quote:

You may want to look at some of the Fluke insulation testers and some of the other insulation testers.

The Fluke I looked at (functionally similar, as far as the 'writing on the box' goes) was almost five times more money. If I was testing motors every day then I wouldn't hesitate to drop the money for Real testing equipment, even an MCA as you suggested.

Mike:

Took a look at the website that you linked.

The instrument, should it operate as advertised, will probably meet with your needs for troubleshooting and even some level of trending (assuming you adjust the readings for winding temperature). The other tests, such as continuity, should also give you some additional level of troubleshooting, within the limits of insulation resistance and DC resistance testing.

Howard