On Mon, 8 Jun 1998, Douglas Shook wrote:
<snip>
> Generally speaking, though, if you want to use the more powerful and
> more efficient three phase motors, you must use a phase converter. You
> actually can make one of these out of two motors and a bunch of horsing
> around.
There are good plans available on the web at one of the metalworking
sites.
> At the other end of the scale, the single speed, static converters only
> cost $228 for a 4-8 HP converter. Although I have not used one, they
> would seem to be appropriate for an air compressor. Three phase motors
> are about 1/2 the price of single phase motors, much simpler and more
> reliable. The converter price could be offset by the price difference
> between the cheaper three phase compressors and the more expensive
> single phase compressors. Just a thought.
A static convertor will start your 3 phase motor, but run it on single
phase. You will have a power loss of approximately one third of your
motor's rating; something to consider for sizing the compressor.
Martin Scarr
|