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26 September 2018

10.Why is megger used to measure insulation resistance and not a multimeter

September 26, 2018 Posted by AK No comments

1. The meggar tester /or insulation tester actually uses a high voltage at its terminals to do the measurements thus being more efficient in driving In a current and then the measurements are made. Multimeter as the name says is used for a variety of measurements but using basically the same moving coil.when a high resistance or very small leakage is to be tested using a multimeter it usually fails because of its in ability to drive a current through a very high resistance circuit and give a correct reading.

2. With a megger tester,a voltage of not less than 500 volts DC is used for testing the insulation resistance of windings.With a multi-tester, the voltage used is not more than 3-volts DC. A megger is specifically designed to accurately measure high impedances. An ordinary multi-meter is designed to measure lower, more finite impedances. A megger is therefore more accurate for the application.

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