From: Michael S. Lorrey (retroman@turbont.net)
Date: Tue Aug 31 1999 - 22:30:13 MDT
ronkean@juno.com wrote:
>
> On Mon, 30 Aug 1999 23:15:56 -0500 "Billy Brown"
> <ewbrownv@mindspring.com> writes:
> > Robert J. Bradbury wrote:
> > > However, the calculation assumes that every person on the planet
> > can> > find *some* use for his 10 kg allocation of robots consuming
> > ~100KW> > of power. Right now most of the people on the planet don't
> come
> > > close to consuming 100KW. A standard house (with 200 Amp service,
> > > probably above average), only pulls 20KW when it is maxed out.
>
> A technicality: Houses in the US are normally fed with 240 volts single
> phase center-tapped, on three wires. One wire is the neutral or ground,
> and the other two wires each carry 120 volts relative to ground, with 240
> volts between the two live wires. The 240 is used for running heat
> pumps, air conditioners, and some clothes dryers and water heaters. The
> 120 is used for most everything else. So when the two live wires are
> each carrying 200 amps, which is what the 200 amp rating means, the total
> power is 240 volts x 200 amps, or nominally 48 KW, assuming unity power
> factor.
However most houses do not have unity power factor, and they also have
harmonic distortion as well, which adds additional load. Typical
residential power factor is around 50% inductive. Additionally, most
loads are not balanced between the two hot wires, so you waste capacity
there as well. Typical operating loads are only a few kilowatts per
house.
>
Mike Lorrey
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