Re: AC/AC power conversion for datacenters

[Jay Hennigan <jay () west net>]

On Tue, 2 Jun 2003, Matthew Zito wrote:

> This is marginally related to the power discussions earlier, but does
> anyone know of a product that steps up 120V AC to 220V AC and is
> reasonably datacenter-friendly?  We're looking at an environment where
> there's no 220V available - but we only need ~7 amps so conversion could
> be possible to my high-school-physics mind.  I've found some products
> that seem to be appropriate, but they're geared towards a more
> industrial purpose.  Is there a rackmount 120->220V converter that
> people out there have used and would recommend?

It's called a transformer.

"Only" 7 amps at 240V is 1.68 KW.  This will be rather large and heavy,
typically the kind of thing more suited to a NEMA box than a rack mount.
It will also consume about 14 amps from the 120V circuit, so it should be
on its own breaker.

You could mount such an item on a chassis with a rack panel if so inclined
but doing such will not likely be in compliance with UL or electrical
codes.

For a more rack-friendly type of solution, some form of switching supply
inverter might work instead of a transformer working at line frequency,
but it will be either expensive or not have a clean sinewave output or
both.  These rectify the input to DC, then use a higher frequency switcher
to generate AC with a smaller, lighter transformer, then electronically
reconstruct a 60-Hz AC output.  I can't recommend a supplier or even say
for sure that such an item is available as a stock unit.

For that type of power consumption, a 240-volt supply (may be 208 depending
on the source feed) is your best bet.  I'd question the "not available"
statement to be sure, as if 208 or 240 isn't available, then 14 amps at
120 is probably going to be marginally available.

-- 
Jay Hennigan - CCIE #7880 - Network Administration - jay () west net
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