Resurrecting a dead generator

Sylvia Else · 2014-12-13T08:36:08+00:00

Having removed the inverter from my dead inverter generator, and replaced such wiring as seemed necessary, I was able to get the generator part running today. Fortunately, the electronic ignition system is separate from the inverter, and was still usable. I looked at the voltage between two of the three alternator outputs with no load, not field current, and the engine running at about half its maximum speed. I got about 600V AC, using just the field from the fixed magnets. I'd expect the first thing the inverter would do with this 3 phase AC would be to rectify it, giving about 850V. This would need to be smoother somewhat, implying capacitors. There are two large electrolytic capacitors visible, rated only at 450V. I suppose they could be in series, though given the tolerance of electrolytic capacitors, there's no guarantee that the voltage would split evenly between them. 850V seems rather a lot. It implies that were the generator running at full speed, and the load suddenly vanished, the inverter electronics would have to cope with a substantially higher voltage before there was time to slow down the engine to bring the voltage back down to something more normal. Perhaps I'm missing something. Things would be of a somewhat more sensible order if there were a common line from the alternator, but if there is, I haven't been able to find it. Any thoughts? Sylvia.

Dec 13, 2014 20 Replies

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makolber 11 years ago

Thats a better service manual than most I would say if you are measuremeing over 500 volts black to black just pulling the starter rope and the engine not running, then you have a measurement error.

Sorry for being repetative here but i want to verify this... The inverter failed and caught fire? The fire was not caused by the engine or gas supply?

Mark

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Resurrecting a dead generator

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