[rescue] Power Requirement Calculations
bdeloria at gmail.com
Wed Dec 13 09:45:16 CST 2006
I got into a bit of an arguement once and what I made simply was a small
jumper extension that was essentially a 1 foot extension cord except I had
the wires exposed (not uninsulated, but rather nolonger jacketed inside the
cord 3 wires together).
I left one wire a bit longer so I could make up to four loops and put it
inside of an amp clamp, this way when you're dealing with lower amperages
and a meter that isn't very sensitive you in essence quadruple the amount of
amperage going through the clamp and divide it by four to get your true
This does however involve powering down your equipment, but it's nice to
have when doing initial setups to get a good idea of UPS load in new
It's also a nice thing to show morons how bad plugging an LJ 8150 into a UPS
On 12/13/06, Sandwich Maker <adh at an.bradford.ma.us> wrote:
> " From: "Clemson, Chris" <Chris.Clemson at softwareag.co.uk>
> " > Mfg. web sites?
> " They only ever seem to give max rating, which seem wildly different to
> " actual use.
> " > How many pieces of equipment are we talking about?
> " About 200. annoyingly most are different makes and models.
> " > Have you considered going to the circuit breakers and seeing
> " > what they are rated for, and using that as a guide? I bet an
> " > electrician could use a probe of some kind to measure the
> called an 'amp clamp' this side of the pond. it actually goes
> -around- the wire to form the magnetic ckt of a transformer with a 1/2
> turn primary.
> " > current on each circuit your equipment is hanging off, but
> " > you'd have to add some to that measurement to account for
> " Yes, that might be the easiest, although it'd be nice to do individual
> " bits as things will get added/removed.
> " > everything getting turned on at the same time and consuming additional
> " > power...
> " True
> " Thanks!
> if you can afford to power-cycle each bit at least twice, you can get
> exact data with an amp clamp and data recorder and a short extension
> cord with the jacket stripped back to expose the hot lead.
> repeating 200 times is laborious and boring, not helped with the
> danger of working with power wiring, but if you need exact numbers
> you'll get them.
> Andrew Hay the genius nature
> internet rambler is to see what all have seen
> adh at an.bradford.ma.us and think what none thought
> rescue list - http://www.sunhelp.org/mailman/listinfo/rescue
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