Extech Instruments MG500 Manual

next previous

MG500-EU-EN v1.0 7/13



TransformerTesting

Transformertestsareperformedwiththetransformercompletelydisconnectedfromtheline

andtheload.Notethatthecasegroundshouldnotberemoved.



Thefivetestslistedbelowwillcompletelytestasingle‐phasetransformer.Notethatatleast1

minuteshouldbeallowedbetweeneachtest.



1. High

voltagewindingtolowvoltage

windingandground

2. Lowvoltagewindingtohighvoltage

windingandground

3. Highvoltagewindingtolowvoltage

winding(picturedatright)

4. Highvoltagewindingtoground

5. Lowvoltagewindingtoground



NotesonMeasuringtheResistanceofaContactororCircuitbreaker

AContactororCircuitbreakermustprovidealowresistancepathtoelectricitywhenclosedbut

shouldprovideahighresistancewhenopen.Astheyage,theircharacteristicsmaydeteriorate

becauseofheavyuse,operationinadirtyenvironment,orotherfactors.

UnusualInsulationResistanceMeasurementApplications

o Specialpaintorvarnishmaybeusedasaninsulatorontransformersandotherelectrical

applications

o Insulatingblankets,suitsandglovescanalsobetested



Connect the

GREEN lead here

Connect the

RED lead here