> On Jul 19, 2016, at 1:51 PM, et...@757.org wrote:
>
> ...
> I've heard sometimes the utility will indeed give you 3phase but you have to
> pay them to replace the transformer and it's very very expensive. Normally
> it's people buying used milling equipment that are after it from my
> experience. There are rotary converters and solid state converters but
> probably not ideal for huge loads.
Anything powered by electric motor above 2 hp or so often comes in 3 phase, and
when you get to somewhat higher power (5 hp or so) it seems to be about the
only option. Lathes and milling machines are good examples.
The expense of a new service for 3 phase is one issue; it may not be available
at all. A lot of US rural areas have a single wire running along the street.
The only way you could get 3 phase service is for the utility to replace that
by 3 wires, for however many miles it takes to get to the spot where their 3
phase service ends.
Rotary converters have a good reputation among home workshop types. You can
build them or buy them. I liked the VFC approach when I realized how
inexpensive a basic one can be, plus I get variable speed and instant reverse
and controlled braking as well.
paul
