[QUOTE=DoubleChevron;1854253]I think a lot of old farms have this. It's not true 3phase. One of my mates has it on his farm. You can get away with far less current pull using "two phase". I pretty sure the phases are 180degrees apart... they must be the two sides off a center tapped trannie (I'm sure google would give the answer in seconds if you searched). I've seen old 240volt motors that have wiring instructions/tappings for 2phase.
I made myself a phase converter for a big grinder a while back. You need to have the correct 3phase motors. They need to be wired delta @ 240 across the phases from memory (check that, don't trust my memory). It worked ok, I just pull started the 2nd motor with a rope around it's pulley. Using cap start too run the 3phase motor ... it just didn't sound happy.
Honestly though?? 3hp motors are cheap in single phase these days .... it's probably going to be cheaper and less hassle just to by the single phase motor to suite. I did miss out on a 5hp single phase (monster sized ancient job) at the closedown of a motor rewinders a couple of years back. I'm still kicking myself for not grabbing it. Imagine the compressor I could run with that :twisted: I'd have to switch off everything in the shed to start it though .... could you imagine the startup current pulled by a 5hp motor :eek: The compressor used to dim half the street with a 3hp motor.
I have a brand new 5HP single phase motor if anyone wants it.
I was going to put it on my car hoist but I moved and now have 3 phase power :)
Love it.
Anyway, the 5HP is for sale if anyone is interested. I paid $700 for it.
Make an offer. A realistic one please.
on another note, 3hp (2.1kW) VSD's are pretty good, Ive got one of these as well. Having frequency speed control beats changing belt configuration every time you want to slow down or speed up your lathe. Its not used anymore since im now on 3 phase.
Cheers,
Phil
