Supercomputers, fishing for information

[Lyle Bickley]

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
> strings.

Here's a "conversion" website:
http://ncalculators.com/electrical/kva-conversion.htm

Cheers,
Lyle

-- 
73      AF6WS
Bickley Consulting West Inc.
http://bickleywest.com

"Black holes are where God is dividing by zero"