Cray J932SE (was Re: Straight 8 up on Ebay just now)
paulkoning at comcast.net
Tue Jul 19 13:08:25 CDT 2016
> On Jul 19, 2016, at 1:51 PM, ethan at 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.
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