[66532] in North American Network Operators' Group
Re: Looking for power metering equipment...
daemon@ATHENA.MIT.EDU (Scott McGrath)
Thu Jan 15 08:58:23 2004
Date: Thu, 15 Jan 2004 08:57:46 -0500 (EST)
From: Scott McGrath <mcgrath@fas.harvard.edu>
To: nanog@merit.edu
In-Reply-To: <200401151339.IAA19611@sigma.nrk.com>
Errors-To: owner-nanog-outgoing@merit.edu
Concur with you need wattage not amperage. There is a 'relatively' cheap
method of doing this however local electrical codes may put a damper on
this type of project.
You put a current transformer on each branch circuit. A 'typical' current
transformer will generate 1Millivolt per Milliampere. You then install a
A/D board in a PC and write a simple application to query each channel of
the A/D. or purchase a commercially available SMNP datalogger.
Scott C. McGrath
On Thu, 15 Jan 2004, David Lesher wrote:
>
> Speaking on Deep Background, the Press Secretary whispered:
> >
> >
> > Question: We are looking for something that sits in the PDUs or branch
> > circuit-breaker distribution load centers, that, on a branch-circuit by
> > branch-circuit basis, can monitor amperage, and be queried by SNMP.
> >
> > Considering there are several hundreds of circuits to be monitored, cheap
> > and featureless (all we need is amperage via SNMP) is fine.
>
> You really want wattage. The power factor of switched supplies
> is far from unity.
>
> Take a look at <http://www.quadlogic.com/transmeter1.html>
>
> Also, recall you sell each watt twice -- once to heat up
> a chassis, and a 2nd time for the HVAC to cool it.
>
>
>
>
> --
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