[plug] Shameless plug <sigh> 60KVA UPS

[Bret Busby]

Mike from West Australia wrote:
> 
> At 10:10 AM 30/4/2000 +0800, you wrote:
> 
> >Is that 700W correct? It seems pretty low for a device with the other
> >specs, and for the price.
> 
> Its about standard for a transformerless convertor.
> 
> >We have a Sola UPS 325/750, which, from memory, gives somewhere around
> >600-700W draw. We run 3-4 computers including two monitors , off it.
> >That UPS cost less than $1,000.
> 
> You are confusing input draw with power capacity.
> 
> >I would have thought, from the other specs, that the UPS for sale, would
> >have a standby draw of around 700kWh.
> 
> Aye ? 700KW is 700,000 Watts for a 60KVA convertor - you are *way* off.
> 
> Standby draw is defined as the invertors cunsumption when batteries are at
> peak
> charge and mains supply is at rated voltage.
> 
> But,
> In the event mains has failed, batteries are supplying load, efficiency at
> that
> point is 92% at full load. ie to Supply 60KVA, then battery consumption is
> 60,000/0.92 = 65217 Watts. Rather less then your 700KW figure !

What, only 92%? What happened to the other 8%? Is this some GST thing?

I had figured, with the specs for the thing and its components,
including the dimensions, and the need for a KATO crane, and a bulldozer
to open the door, that it would supply at least 12 hours, at 60kW, which
would give 72kWh, and, after rounding down to the nearest 10 kWh, 70kWh. 

P=VI; therefore kVA (voltage x current) = kW. 
(The instantaneous power to the load is simply the product of current
and potential difference - p539, Elementary Classical Physics, Volume 2,
Weidner & Sells, 2Ed, 1973)

You notably did not state any specs for the backup draw and duration (5
minutes? 10 minutes? 24 hours?)

> 
> Where do I send the bill for the engineering advice ;-) ?

To the person who did not clearly state all the specs for this device
that is sought to be flogged on a Linux mailing list. Do you have Linux
drivers for it? Or, do the drivers need to have stationery engine
drivers' tickets, due to the size of the thing? Do you have Linux
drivers for the crane? Or, do they need to be TWU drivers?

:^))

> 
> Rgds
> 
> Mike


-- 

Bret Busby

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