RE: Monitoring household power consumption I purchased a power meter from Brand electronics.  They have a few 
different models.  There is one that is suitable for measuring the costs of 
one device and there is a larger one that has to be hardwired into your 
house.  Check out http://www.mint.net/~ebrand/
They are pretty nice little devices.

		-Jeremy

>Actually, that little black band is a relic of earlier days when people
>(like myself) had jobs that occasionally required them to sit with a
>stopwatch and count turns.  A slide rule was then used to calculate power
>consumption.  Each meter had a unique "meter factor" which entered into the
>equation.  You actually might not have such difficulty using an LED
>emitter/detector pair to count turns if you shield the meter from ambient
>light.  Of course, if you remove the glass dome to get closer to the disk
>the power company will send the sheriff...
>
>The problem with the meter disk is it only spins fast if you are using a lot
>of power, so if you want to track individual small appliances you would have
>to run them a really long time with everything else unplugged.  Remember,
>many devices like TV's , radios, doorbells, stoves, ovens, HVAC, and
>telephones, or anything with a built-in battery charger or clock, or
>anything that runs from a "wall wart" (AC adapter), or anything that uses
>refrigeration, or has a built-in microprocessor; will use power even when
>shut off.  Just for the hell of it, turn off everything you can think of,
>then take a flashlight and go watch that disk...
>
>All of which is to say that finding the Circuit Cellar article referred to
>by Tom Brusehaver is a good idea.  Presumably the article provides some way
>to convert the coil output to DC.  You could also buy/borrow/rent a current
>meter or current probe for your multimeter if you own one.  These use the
>same principle, except the toriod is hinged so you can snap it over the hot
>wire without having to disconnect anything.  You can then make a power
>survey for each circuit in your house by snapping the meter over the
>relevant wires in your breaker panel.  To run a long term survey for the
>whole house you need to make and calibrate your own coils.  Note that if
>your house is wired in the normal way you need two.

_______________________________________________________________
                               Jeremy Green
        jag@world.std.com           jag@brownout.com
       http://www.brownout.com mailto:jag@brownout.com

