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Re: Average, RMS and Power Factor made easy!



Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <Tesla729-at-cs-dot-com>

In a message dated 1/10/01 4:46:57 PM Pacific Standard Time, tesla-at-pupman-dot-com 
writes:

<<  "David Dean by way of Terry Fritz <twftesla-at-uswest-dot-net>" 
<deano-at-corridor-dot-net>
  >>

<< Sort of like the horsepower rating in a
car engine. Take two cars of the exact same make and model, one with a 90HP
4 cyd. and the other with the optional 140HP H.O. V-6, and of course the V-6
will feel a bit more spunky to the driver. Rarely, if ever, will either
engine deliver its rated horsepower under actual driving conditions, and in
the case it does, it will only be a peak, of short duration. >>>

Hi David , all,
I've noticed this issue of "peak power" on motorized electrical appliances.
Case in point: My  20 gal. Shop Vac is rated at "6 HP peak" with the "peak"
in finer print. Yet the current that it draws is 11 amps and 11 A x 120 V 
(RMS of course :-) = 1320 watts ( I assume RMS ). Yet we know that 746
watts is actually equal to 1 HP. So 1320/746 dosen't even come up to 2
average horse power, even though it is rated at 6 peak HP. I think the bot-
tom line is that true power vs instantaneous power is aften confused and 
"true power " is even more complex to determine in the dampened Tesla
circuit than in typical CW AC circuits, which is complicated enough itself.
I'll let the true engineers hash out the further details on this issue :^)

MY $.02,
David Rieben