Supercomputers, fishing for information
lbickley at bickleywest.com
Tue Nov 8 11:39:29 CST 2016
On Tue, 8 Nov 2016 09:33:37 -0800
Guy Sotomayor Jr <ggs at shiresoft.com> wrote:
> > On Nov 8, 2016, at 9:22 AM, Paul Koning <paulkoning at comcast.net>
> > wrote:
> >> On Nov 8, 2016, at 12:08 PM, Guy Sotomayor Jr <ggs at shiresoft.com>
> >> wrote:
> >>> On Nov 8, 2016, at 8:47 AM, Jon Elson <elson at pico-systems.com>
> >>> wrote:
> >>> On 11/07/2016 10:31 PM, Jon Elson wrote:
> >>>> On 11/07/2016 07:59 PM, Mark Linimon wrote:
> >>>>> On Mon, Nov 07, 2016 at 11:23:58AM -0800, Chuck Guzis wrote:
> >>>>>> But if you're a suburban resident living on Mulberry Street,
> >>>>>> anything but single-phase is pretty much out of the question.
> >>>>> Oh, you can get it -- but be prepared for a large hassle.
> >>>>> A former neighbor had a 440V 3-phase Italian lathe in his
> >>>>> backyard shop, among other toys. After he was laid off from
> >>>>> his aerospace job doing machining it was how he made his
> >>>>> living. He was a very handy person to know :-)
> >>>>> mcl
> >>>> I have two 3-phase machines in my shop (Bridgeport mill and
> >>>> Sheldon lathe) and run them each off a properly-sized VFD.
> >>>> 2-phase in, 3-phase out, plus variable speed and dynamic braking.
> >>>> Jon
> >>> And, of course, that is really SINGLE-PHASE power on 2 wires,
> >>> just to save anybody the trouble of correcting my error.
> >> I’m looking to have to do something to get 3-phase for the IBM
> >> 4331 gear. I haven’t quite added up the power requirements yet
> >> but I’m guessing its going to be in the 10-15kVA range. Since the
> >> power to all of the gear is really split between 3 loads (string
> >> of 4 3340 drives, 3803 control unit + 2 3420 tape drives and 2821
> >> control uint + 1403 printer + 2540 card reader/punch) I need to
> >> figure out if it’s best to have one big converter or 3 smaller
> >> ones. It’s unlikely that I’d be running all of the peripherals at
> >> once. The 4331 itself runs off of single phase 220v.
> > A VFD is a good option and may be quite economical if you get one
> > of the low cost simple ones. I have one (3 hp model for my lathe)
> > that cost only a bit over $100, though the price has gone up
> > since. (Westinghouse TECO brand.) VFDs specified for single phase
> > input tend to stop around 3 hp, as far as I have seen. Rumor has
> > it that higher power units will also work (possibly with some
> > derating) even though they claim to be 3 phase input, when you feed
> > them just one phase on 2 of the 3 wires. I haven't tried that (but
> > it matches how my VFD is connected).
> > The other option is a "rotary converter". Basically that's a 3
> > phase motor connected to one phase power (with a start and run
> > capacitor); it generates the missing phase roughtly in dynamotor
> > fashion. Those can be built (articles on the web) or bought from
> > machinery supply companies such as Enco; they show models up to 20
> > hp, i.e., about 15 kW. When I was looking into converters, I found
> > VFDs to be the less expensive option. The instant reverse and
> > variable frequency features were also attractive for lathe use; for
> > powering computers that would not apply. Well, not unless you need
> > 400 Hz for your Cyber 6600 -- in which case you'd need to check the
> > VFD will go that high, not all do.
> > Given that you have a number of smaller devices and that not all
> > might need to run, several smaller converters sounds like a good
> > option, especially if that gets you into the "economy VFD" range.
> Yea, that’s what I’m struggling with. The issue is that the control
> units power the devices that are connected to them (from what I can
> tell), so I have to power the entire string as one unit. The same
> goes for the 3340’s - the entire string is powered as a unit. The
> string of 3340’s need ~5kVA (I don’t know how that translates to
> HP). I’m still trying to figure out the requirements for the other
Here's a "conversion" website:
Bickley Consulting West Inc.
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