I've got a big 560 uF, 400 V capacitor and I've tested it with a meter and the capacitance is within spec, same the ESR and it has a vloss of 0.8%. So all seems fine but then I came across this video geizer test'in. In his case there were obvious signs of capacitor damage so it was easy to see what was wrong even though the meter said it was fine.
He did the same and appeared to have a good capacitor capacitance and the ESR was good but when he connected up to a power supply as he cranked up to voltage the more it leaked.
So what tests should be performed?
And given that I do not have a power supply that will go up to 50 V how can I test the leakage at higher voltages or do some test in substitution?
Best Answer
This circuit from Max Robinson shown below has worked well for me only instead of the transformer I used the primary of an old switch mode charger that provides a stable 340vdc and isolation but there is no reason the circuit below will not work just as well. Also I used my cheap dvm he suggests a parallel 10M but I am not sure why.
The leakage voltage is ILMeasured = V / R.
In my case the leakage was 30V after 10 minutes for a 560u capacitor with 220k series resistor.