Hello,
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?
Thanks,
Matt
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?
My suggestion, which I have never tried, is to get a UPS with the right
wattage and that support 240V out but variable (90V-300V) input. Just a
thought.
PS Please don't make the mistake that a certain US supplier made with kit
shipped to UK and specify 16A connectors which required special wiring (over
standard 13A in the UK) as at 240V the current is lower by 240/110 
Measure watts, not amps. Unless you have a weird PSU of course.
Peter
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.
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?
My suggestion, which I have never tried, is to get a UPS with the right
wattage and that support 240V out but variable (90V-300V) input. Just a
thought.
Depends on your hardware obviously but I suspect it'll be cheaper to replace the
PSU with one of the same voltage as the supply than messing with ups etc
Steve
As you say, depends on the hardware, but take for example the Cisco GSR
where the AC PSU only comes with a 220V option - not a problem for us in
the UK, but more hassle for putting the routers in the USA. Of course, DC
is an option, but high-amppage DC scares me 
Simon
You don't mention why you need this -- as someone mentioned, 220v/7a is
110v/14a.
If this is a piece of electronic equipment, it may be cheaper to simply
replace the power supply with a 110 supply.
If it's something with a 220v motor, you might want to make sure that it
isn't also looking for 3 phase power. (Not that I really know the
difference -- just enough to know it's something to watch out for).
-Chris
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?
This is from www.grainger.com Their Item # <Grainger Industrial Supply - MRO Products, Equipment and Tools
Product Category: <Grainger Industrial Supply - MRO Products, Equipment and Tools > <Grainger Industrial Supply - MRO Products, Equipment and Tools > <JavaScript:fun_catLowest('-1610648591')>Transformers
Description
Transformer 7.5K Watt, 1 Phase (190 to 220)/(380 to 440) Volt Primary 110/220 Volt Secondary
Grainger Item: 2CN75
Price (ea) : $810.00
Manufacturer: SQUARE D
Mfg. Model#: 7S67F
<javascript:popWin('/help_uom.html');>Ship Qty : 1
<javascript:popWin('/help_uom.html')>Sell Qty(Will-Call) : 1
Usually Ships : Special Order
Catalog 394 Page: N/A
Your website says you are located in NYC. If this is for you and not for a client in Congo, your 120V feed either comes from one leg of a 120/208V three phase service or 120/240V single phase service. If you take any two hot legs in either case, you will be able to power your equipment directly with either 208V or 240V. You will probably need to pay an electrician to do this work for you, but it will probably be easier and much better than running an auxiliary transformer. You should definitely consult an electrician to determine the best solution for your needs. Another option is to replace the power supply in the unit in question. Most equipment vendors now make auto-sensing world power supplies which will work on just about any voltage from 90VAC to 250VAC for homogenization of their products worldwide.
-Robert
Tellurian Networks - The Ultimate Internet Connection
http://www.tellurian.com | 888-TELLURIAN | 973-300-9211
"Good will, like a good name, is got by many actions, and lost by one." - Francis Jeffrey
Here's a 3KW one for E389:
http://www.taunus-transformatoren.de/transformers/transformers_110_120_220_230_240.htmlMatthew Zito <mzito@gridapp.com>,
(Actually, you don't need a two-coil transformer - a one-coil transformer
with a tap in the middle will do, and those may be even cheaper).
Note that transformers do NOT change frequency from 50Hz as in EU to 60Hz
as in US; typically this is not a problem for electronics power supplies,
because the first thing they do is rectify the mains voltage to DC, but
you may want to check that with your equipment specs or with their tech
support.
Note also that if your higher-voltage equipment requires multiple phases,
you're out of luck. The "220V" in US is usually two 110V feeds with 180
degrees shift, so there's a zero-point wire as well, allowing asymmetrical
loading. This kind of supply may be provided with a transformer, but I've
never seen one like that.
The EU multi-phase power is typically 3-phases with 120 degree-shifted
230V supplies, there's no way to convert to it from single- or dual-phase
power to it w/o electronic invertor or motor-generator combination.
--vadim