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

ethan at ethan at
Tue Jul 19 12:51:59 CDT 2016

> Right... and in my area (hardly unique, I'd wager), you cannot get
> 3-phase in residential areas.  The shared transformers on the poles
> don't provide it and you can't pay them to add/change a transformer.
> You have to be in a commercial area to get that.  Fortunately for me,
> my tastes in minicomputers runs "small", so my largest machines have a
> 30A 110V single-phase plug (frequently to an H-861, but not always).

The Cray is single phase, the only thing I've ever owned that was 3 phase 
was the laser stuff. Now my solid state laser projector uses 100 watts and 
producsed half the power of the argon that used to take 3ph @ 30A (and 
still tripped the breaker sometimes.)

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.

The Cray uses 5 x Pioneer magnetics power supplies that I believe are 
identical to those in the Sun E10000. The smaller rack with the VME 
chassis and hard drives -- good chance the power supplies are okay with 
110/120v. The disk trays at least are just good quality SMPS that do 5/12 
in each drawer (was 4 x 9GB full height disk per drawer.)

The Pioneer Magnetics supplies that run the computational part are like 
48vdc out @ 5000W each.... so not sure if they would run on 120V but if so 
-- it would be a real high amperage load.

Note - in the modern datacenter in the US it's not uncommon for everything 
to be run on 208, but everything would run on 120.

Ethan O'Toole

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