On Friday 31 January 2003 06:20 pm, Peter Jay Salzman wrote: > hi rod, > > well, the math looks good, but you most likely knew that anyhow. > > the relative error between 325 watts and 250 watts is about 23%. pretty > high, imho.
Well, either 250W is "23% too low" or 325W is "30% too high". :-) > the implicit assumption is that the dial's rotational speed increases > linearly with energy consumption. i have no inner feeling for whether > that's true or not. however, i can tell you that the power delivered by > an harmonic wave of any sort is proportional to the *square* of its > amplitude. that's kind of counter intuitive, and was just meant to > illustrate that linear increase in angular speed may not result in > linear increase in consumed power. The meter seems all mechanical, just gears, and the dials measure straight KWH, so I'm pretty sure the relationship is linear. > but i'm _very_ interested in hearing PG&E's response to this. please > send a followup to this when you have more info! Sure. I'll be doing some more careful testing first. Checking that 100 revs/KWH assumption will be a pain. Thanks for the feedback. -- Rod > pete > > ps- what kind of bulb consumes 250 watts? a french fry lamp? :) > > > begin Rod Roark <[EMAIL PROTECTED]> > > > I got my first electric bill at the new house; looks too > > high. So I decided to do an experiment. > > > > Outside the house is an electric meter. It reads KWH > > accumulated on 5 dials, and has a horizontal platter that > > appears to spin about 100 revolutions per KWH (anyone know > > if this is exactly true for a standard meter?). > > > > So I figure that means 10 watt-hours per rev, or 36,000 > > watt-seconds per rev. > > > > I timed one revolution with most things in the house turned > > off. 45 seconds. Then I turned on a 250W light bulb and > > timed it again. 32 seconds. So: > > > > 36,000 watt-secs / 45 secs = 800 watts > > 36,000 watt-secs / 32 secs = 1125 watts > > > > 1125 - 800 = 325 watts -- for a 250W bulb. > > > > How come? Should I complain to PG&E, or is there some > > gotcha that I'm missing? > > > > Thanks, > > > > -- Rod _______________________________________________ vox-tech mailing list [EMAIL PROTECTED] http://lists.lugod.org/mailman/listinfo/vox-tech
