Posted by David Sherman on Tuesday, October 03, 2006 at 10:14PM :
In Reply to: Re: OT - Single Phase to Three Phase RPC's posted by Dave F on Tuesday, October 03, 2006 at 9:54PM :
Motors on hydraulic power units are usually pretty small (1HP or less), which does make it cheaper just to replace the motor. But Jack has several machines, and at least one of them is 15 HP. Single-phase motors of 10 HP or more are rare. The great advantage of 3-phase motors for home use is that they are cheap to free, and much of the good old industrial shop machines one can sometimes get pretty reasonable come with 3 phase motors. I would generally say that if you're looking at over 5 HP, or multiple machines, it's worth figuring out a 3-phase system. Turnkey converters are expensive, but jerry-rigging one from used parts can be pretty cheap. I have a good pile of assorted 3-phase motors ranging from 1 to 20 hp, most in the 5 hp range, that I got for $1 apiece from a guy who didn't want to move them. I haven't put any of them to use yet, but when I get my sawmill up and running, I'll use a lot of them to convert old belt-driven machines to electric power. The mill will have 3 phase because it'll have to run off a diesel genset since there's no utility power available. The main mill motor will be 40 hp.
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