[time-nuts] Power monitoring

[Stanley Reynolds]

You may want to look at the one wire weather stuff, monitor via ham radio or Internet, if you roll your own. Should be no problem to call your cell phone if something is wrong.
 
Yes they make "computer room monitors" (google the phrase) low end models in the $200 range and full featured ones for $500-$1000 



----- Original Message ----
From: Hal Murray <hmurray at megapathdsl.net>
To: Discussion of precise time and frequency measurement <time-nuts at febo.com>
Sent: Thursday, April 17, 2008 1:10:11 PM
Subject: [time-nuts] Power monitoring

My power went out the other day.  That reminded me that I've always been 
slightly curious about that area.

Are there any not-expensive boxes made for this?  Or something that shows up 
on eBay occasionally?


If I was doing it myself, I'd start with a low power (quiet) PC and a UPS.  
Then I'd have a platform that could monitor other things too, like 
temperature.

  Step 0 is just to measure when power is/isn't there.
    I assume the UPS has a signal for that.

  Step 1 is to measure the voltage.
    This takes an A/D.  The standard PC audio input might be appropriate.  
I'd probably use an AC wall-wart transformer for isolation and a couple of 
resistors to get down to a reasonable voltage.

  Step 2 is to catch dips and spikes.
    That's just software behind the A/D.  (assuming the A/D is fast enough)


As long as I'm dreaming...  Suppose I wanted to measure the power my whole 
house is drawing.  What's available along the lines of a current transformer 
on the main lines?  My first thought is that nobody does that (for homes) so 
it's probably horribly expensive.  On the other hand there is a lot of 
interest in energy conservation these days so it might only be somewhat 
expensive.





-- 
These are my opinions, not necessarily my employer's.  I hate spam.




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