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Thread: Hi-Pot Test

  1. #1
    Join Date
    Nov 2006
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    15

    Hi-Pot Test

    Can anybody tell me under what condition, a packaged refrigeration system with scroll compressor, should be hi-pot tested? Can we do this with system chrged? It can be done without system charged but in reality, the unit is charged and shipped to the customer and system should be safe with charge in the system. How do we resolve this?

  2. #2
    Join Date
    Mar 2007
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    Myrtle Beach, SC
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    2,919
    Quote Originally Posted by behmin View Post
    Can anybody tell me under what condition, a packaged refrigeration system with scroll compressor, should be hi-pot tested? Can we do this with system chrged? It can be done without system charged but in reality, the unit is charged and shipped to the customer and system should be safe with charge in the system. How do we resolve this?
    Do the Megger test only under pressure, never in a vacuum. Any time you think there is acid or moisture in the refrigeration system, the megger (Hi-pot) test will tell you how bad it is. I have always been told to test at no more than double working voltage. IE, a 240 volt compressor should be tested at 500 volts max.

    Less than 20 megs is bad, 20 to 100 megs change oil and/or driers, over 100 megs is fair, over 200 megs is good, over 500 megs is best.

    Also, leave the megger on for 10 minutes, the readings should continue to rise. If you test a system that has not run in several weeks you will get low readings.
    Last edited by Kevin O'Neill; 06-03-2009 at 04:19 PM. Reason: additions
    Remember, Air Conditioning begins with AIR.

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