Re: Looking for power metering equipment...

[Scott McGrath <mcgrath () fas harvard 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.
>
>
>
>
> -- 
> A host is a host from coast to coast.................wb8foz () nrk com
> & no one will talk to a host that's close........[v].(301) 56-LINUX
> Unless the host (that isn't close).........................pob 1433
> is busy, hung or dead....................................20915-1433