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Re: Power 720 (8202-E4C) - 208v vs. 110v



fixed

Rob,

AFAIK most servers have staggered spin up for the disks, so the worst start
up current would be blower/cpu related and shouldn't be that big. I have a
client that has a BladeCenter H chassis, when cold starting the blades they
cant start all 14 at the same time because it overloads the UPS (bad UPS
sizing, i know)...


On Mon, Oct 28, 2013 at 3:56 PM, <rob@xxxxxxxxx> wrote:

Can I assume that startup may be significantly different?


Rob Berendt
--
IBM Certified System Administrator - IBM i 6.1
Group Dekko
Dept 1600
Mail to: 2505 Dekko Drive
Garrett, IN 46738
Ship to: Dock 108
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Kendallville, IN 46755
http://www.dekko.com





From: DrFranken <midrange@xxxxxxxxxxxx>
To: Midrange Systems Technical Discussion <midrange-l@xxxxxxxxxxxx>
Date: 10/28/2013 02:48 PM
Subject: Re: Power 720 (8202-E4C) - 208v vs. 110v
Sent by: midrange-l-bounces@xxxxxxxxxxxx



In theory the power supplies run a smidge cooler but not so you could
measure. The server itself uses all DC internally so nothing changes
there.

Since the total power of 208 is 'about' double at the same amperage you
can use lighter power cords on 208. In THEORY at 208 you could use a 20
AWG power cord to carry 1750 Watts but at 110 you'd need a 16 AWG power
cords to carry the load. In practice I believe IBM Ships 14 AWG cords
for everything. I would be comfortable with 18AWG at 208 volts (100%
larger than minimum) and 14 at 110V (almost 100% larger than minimum.)

That said, remember too that in normal use the load is split across two
supplies AND will not be even close to 1725 watts total. Remember that a
740 uses the same power supplies with two processor cores and holds
twice the memory. We've measured 720s with 8 disk units running at about
300 watts total or only 150 Watts per line cord. That's less than 1 Amp
per line cord at 208!

- Larry "DrFranken" Bolhuis

www.frankeni.com
www.iDevCloud.com
www.iInTheCloud.com

On 10/28/2013 1:17 PM, Brian wrote:

The 5603 power supply in a 720 (8202-E4C) is rated at 1725 watts so a
110v
20A circuit should be capable of supplying plenty enough power. That
being
the case, is there any advantage to powering a model 720 with 208v input
vs.110v input?

TIA,
BJ

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