Cray J932SE (was Re: Straight 8 up on Ebay just now)

[Paul Koning]

> On Jul 19, 2016, at 12:53 PM, Mouse <mouse at Rodents-Montreal.ORG> wrote:
> 
>> [...], especially since most electrical installations (even domestic)
>> are 3-phase.
> 
> This, I believe, must be location-specific.  In North America, it is
> usual for domestic electrical feeds to be only two-phase (that is, they
> are the two sides of a centre-tapped secondary - the two hot wires are
> 180 degrees out of phase with one another).

Yes, and time dependent as well.  I grew up in Holland; in the 1970s, we had 3 phase in our house because we had an electric cooking range.  But ours was the only house in the block with 3 phase service; all our neighbors cooked with gas.

In the USA, if you're a home owner with a need for 3 phase power, you probably have to get a phase converter.  Fortunately those are not hard to get, and solid state ones (variable frequency motor controllers) can be rather inexpensive.  I have one for the 3-phase motor on the lathe in the barn.  $100 for a 3 hp model, as I recall, though that may have been on sale.  VFCs should even work for 3 phase 400 Hz power, just the thing if you have a CDC Cyber tucked away in the basement.

	paul