Just read your last reply, Robert. The problem with 'top up' is synchrononisation of the ac and the need to have a high quality waveform for anything other than resistance devices or lighting. Most other stuff these days has a chip fitted somewhere....
Trawling the net, I see some folks claiming modified SP capacitor motors can be used as generators, so I may be wrong. Here's one forum:
http://www.fieldlines.com/board/index.php?topic=131100.0 THE KILLER: WHAT YOU CAN DRIVE:
http://www.qsl.net/ns8o/Induction_Generator.html
