Megger insulation tester low voltage

[John700]

I have a Megger Series 3 MK lll insulation tester, I have tested the output voltage when I crank the handle and it is around 300volts, ( it's a 500v megger) what component inside is likely to be faulity?

[Silicon]

What is the input resistance of your voltmeter when you measure the output voltage of the Megger?

Your voltmeter will simulate faulty insulation as far as the Megger is concerned, and may drag the test voltage down.

[The Philpott]

If you have a voltmeter/multimeter with a high input impedance (10 megohms is common these days) and it still shows this low reading, it could be down to a faulty capacitor in the Megger.

My Megger is one of the miniature ones so we're not necessarily comparing apples with apples, however i did manage to restore full voltage with a new capacitor (which of course was a different size and shape from the original)

Dave

[John700]

I was measuring the voltage with a 10M Ohm multimeter, I will have a look at the capacitor.