I've just found out that a motor that I need to convert to single phase running is delta wound and 415 volt. Why would they configure a 2.5HP 3 phase motor like that? Probably just to really piss someone off 30 years later I suppose.
Anyway this means a remotoring job so if anyone has a 1.5-2.5HP foot mounting motor , dual voltage, ideally with a 1" shaft I'd like to hear. I have a 3HP flange mounting version but its too big for the space - but is available for px if wanted.
Thanks
Charles
Not really, 3-wire 3-phase without a neutral was pretty much standard practice in machine shops since the crust was formed on the earth. neutrals are a pain in transformers and star -connected equipment, and gradually died out for machine tools etc.
We haven't used Star input in our big chargers for some years, as there are similar problems with circulating neutral currents, so we use Delta input and Star secondaries, but don't use the neutral point for the rectifiers.
I think we have a dual-voltage one that I mentioned to you a few weeks ago?
Peter
-- Peter & Rita Forbes Email: snipped-for-privacy@easynet.co.uk Web:
Confessional time.
The problem that I was suffering was that the fuse supplying my home-made 3 phase convertor kept blowing when I tried to start the motor. I assumed that this motor was step too far for my convertor and that I'd have to make a single machine capacitor start setup for a 3 phase motor from the Jim Cox book. Hence my removing the motor to re-connect it in delta. Removing the motor was a pig and involved making cranked spanners etc.
Then I has my Homer Simpson moment - I wasn't feeding the starter with the true 415volt. It was trying to throw the contactor on the capacitor driven phase. Swap the 3 phases round and bingo - it works. Then I had to put it all back together (but at least I had the custom-made spanners.) Now it runs and starts like a beauty.
You live and learn.
Charles
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