Subject: (usr-tc) Power Consumption

From: Marshall Morgan <[email-masked]>
Date: Thu, 23 Nov 2000 03:42:27 +0000

If I have 14 DSPs, 1 HiperNMC and 2 ARCs plus an integrated fan tray what
will be the amps required at peak and nominal using a single or dual -48vDC
130A power supplies?   I need to make sure the 25A listed on the PS is not
right as I cannot find any GMT fuses and panels that support more than 15A's
for each fuse and 50A per distribution panel (using Telect panels)
http://www.telect.com/products/category/index.cfm?category=TRADFUSE

Marshall Morgan

Internet Doorway, Inc (aka NETDOOR)
http://www.netdoor.com

601.969.1434 x28 | 800.952.1570 x28 | 601.969.3629 x28 | Fax 601.969.3838

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From: Clayton Zekelman <[email-masked]>
Date: Mon, 27 Nov 2000 16:59:07 +0000

Short answer:  you can't.

Long answer:  GMT fuses, although available up to 15 Amps, are generally
not used in applications above 10 amps - you start running into fuseholder
constraints, etc.

You should really be using either KTK or NRN style fuses, or better yet,
breaker panels.  See www.argus.ca - they make a nice selection of DC breakers.

We use a model from Telect also with an a/b fuse split with a mix of 4 GMT
and 4 KTK per side.

P/N 009-8004-0100

> "help" to the same address.  Do not use quotes in your message.
---
Clayton Zekelman
Managed Network Systems Inc. (MNSi)
875 Ouellette Avenue
Windsor, Ontario
N9A 4J6

tel. 519-985-8410
fax. 519-258-3009

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From: Marshall Morgan <[email-masked]>
Date: Mon, 27 Nov 2000 17:21:12 +0000

Clayton,

While I appreciate the breaker info, the real question is how many amps does
it draw - that way I know if I am going to have a breaker issue or not.  All
the Telect panels are all tied back to a real breaker panel that has 15-30a
breakers (depending on the guessed load).

Marshall Morgan

----- Original Message -----
From: "Clayton Zekelman" <[email-masked]>
To: <[email-masked]>
Sent: Monday, November 27, 2000 8:40 AM
Subject: Re: (usr-tc) Power Consumption

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From: Clayton Zekelman <[email-masked]>
Date: Tue, 28 Nov 2000 19:08:51 +0000

>breakers (depending on the guessed load).

One of our POPs has 6 TC shelfs with 10 DSP's each.  The TC shelfs plus all
the ancilliary optical and routing gear draws 90 amps or so from our DC
supply.  Most of the other pieces of equipment's draw doesn't amount to a
whole heck of a lot, so lets assume the TC's draw around 70 amps of this.
That would bring the consumption per shelf to around 11 amps.  Remember,
that there is inrush current when powering the units up, plus you may want
a bit of a safety margin on top of it to avoid false trips, etc. It really
looks like its outside of the GMT range, or at least pushing the limit on
the higher end of the GMT range, particularly in the case of a failure of
one of the power feeds if you're running load sharing supplies.

We breaker our TC's at 25 A

The only real way to measure it of course is to place a fixed value shunt
in line with DC supply, and measure the voltage drop across it, and
calcuate the current draw.
---
Clayton Zekelman

tel. 519-985-8410
fax. 519-258-3009

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From: Aaron Nabil <[email-masked]>
Date: Wed, 20 Dec 2000 13:36:42 +0000

On Tue, 28 Nov 2000, Clayton Zekelman wrote:
>  . . .

The other "real way" is to use a clamp-on DC current probe.  The
significant advantage being that you don't have to interrupt the circuit.

--
Aaron Nabil

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