Re: Power Query

["B Fuhrmann" <b-fuhrmann-usenet@xxxxxxxxxxxxxxxxxxxxxxxxx>]

"Beamer Smith"  wrote ...
>A bit of a stretch for this group but the experts seem to be here.
> Our building wants to install seperate meters for our power in part to
> mitigate the expence of the condo's  power bill.
> The building is 208V  but most abbliances are 220. I know for example
> that my mother can boil a pot of water in about 5 minutes on her 220
> service and 22 stove (not new or efficient)  but on my 208 service and
> 220 stove it takes much longer.
> Q: Am I paying more to boil a pot of water or not?


No.  You pay for power by the Killowatt Hour (KWH).  1 Killowatt Hour = 1
Kilowatt hour regardless of the voltage that it is delivered at or the how
fast you use the energy.
You pay the same for using:
    4.55 Amps @ 220 volts (1 KW) for 1 hour,
    4.81 Amps @ 208 Volts (1 KW) for 1 hour,
    83.3 Amps @ 12 Volts (1 KW) for 1 hour,
    .455 Amps @ 220 volts (0.1 KW) for 10 hours,
    .481 Amps @ 208 Volts (0.1 KW) for 10 hours,
    .833 Amps @ 12 Volts (0.1 KW) for 10 hours.

Watt Hours are a measure of engergy used, like calories.
1 watt hour = 860.42 calories
Heating a cup of water from 72 def F to 212 deg F (but not boiling it) takes
33,122 calories or 0.385 KWH.
That ignores any heat that is wasted in the process (heating things near the
stove) and does not include turning any water into steam (actually boiling
it).

The effect on your stove of running 208 instead of 220 volts is that the
heating elements will not draw energy as fast.  Looking at the example
above, a resistive heater that is designed to run at 1KW @ 220V will have a
48.4 Ohm resistance.  Using that same 48.4 Ohm heating element on 208 volts
gives us a 4.30 Amps or 0.895 KW.
To use the same energy that the 220V heating element uses in an hour, you
would need to run the 208V stove for 1 hour and 7 minutes.

The only limitation is that your highest heat is not quite as high.
The payback you get for that is that the heating element will last a little
longer because it is not running as hot.





--
Bill Fuhrmann
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