[ExI] jobs craved
spike66 at att.net
Wed Nov 25 03:20:59 UTC 2009
> ...On Behalf Of Brent Neal
> Subject: Re: [ExI] jobs craved
> On 24 Nov, 2009, at 19:58, spike wrote:
> > When we talk about the amount of power we used this month,
> it requires
> > two units, kilowatts and hours.
> Actually, its not really appropriate to refer to "power used this
> month," you should really rather say "energy used this
> month." Power
> is a rate.
> Yours in absolutely excessive pedantry,
> Brent Neal, Ph.D.
I could have said power-hours used this month, or power-time used. Since I
was demanding strict unit accuracy, I must demand it of myself. Of course,
if we are indulging pedantry, energy use wouldn't be completely sufficient
either. If using one kilowatt for 1000 hours were exactly equal to using
1000 kw for one hour, then it would be energy use, but these are not
*exactly* equivalent, because of resistance in the wire upstream of your
meter. The 1000 kw load would heat the wire more and increase its total
In some rather extreme cases power factor is significant. I wouldn't have
thought of that except for recently having to size an electric pump for the
ranch in which I had to account for power factor in order to maximize
efficiency in water delivered per dollar.
Thanks Dr. Neal!
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