Mike Lee - Team Banana Racing wrote:
>
> With all this talk about 220V, I've got a question. Our house is getting
> close to be finished now, and the builder will be putting in a 220V "dryer"
> style outlet. By "dryer", I assume he means the type of receptacle a dryer
> can plug into. From the sounds of it, I think I can safely infer that it
> is single phase also. Since this hasn't been put in yet, and is subject
> to change, I'd like to know what additional work is necessary for 3 phase
>220V,
> and if it's a reasonable thing to have in a "normal" garage/workshop (strictly
> residential suburbia).
>
> Thanks,
> Mike
Hi Mike and Listers,
Most residential areas are wired only for single phase, 3 wire 220VAC.
If you have a run through your neighborhood that services a
commercial/industrial area downstream, then you may be in luck.
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.
However, I have seen CNC, variable speed, high amperage three phase
equipment run off from normal single phase, residential 220VAC with a
rotary phase converter to great results (my next-door neighbor has a
three-phase, $28,000 CNC machine running on single phase using a phase
converter). If you look at your MSC catalog on page 1934, you will see
a variety of three-phase converters for anywhere from 1 to 100 HP
motors. The only types I have personally seen working are the rotary
converters. The price for a standard 5HP rotary converter is $780. For
a heavy duty converter it is $999. I know these things work--my
neighbor has been using them for years.
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.
doug
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