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From: gdw@harpo.UUCP
Newsgroups: net.consumers
Subject: Re: Re: power/energy meters
Message-ID: <2678@harpo.UUCP>
Date: Wed, 27-Mar-85 08:44:18 EST
Article-I.D.: harpo.2678
Posted: Wed Mar 27 08:44:18 1985
Date-Received: Tue, 2-Apr-85 08:25:50 EST
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Nf-From: !gdw    Mar 27 08:44:00 1985

Leave blank

The watthour meter on the side of your house goes to
great pains to make sure it properly includes the effects
of phase angle. A modern meter can measure the
real part, as opposed to magnitude that neglects phase
angle, to an accuracy of 2% at power factors as low as
0.3. In addition, the voltage calibration is even better
from below 90 volts to over 250 volts. They have a slight
sensitivity to frequency variations, although this is a
negligable effect because the frequency is well controlled.
The only thing they're poor at is accounting for the
effects of harmonics.

Therefore, if you have a resistive load, during a brownout
the meter will drop as the SQUARE of the voltage. Also,
if you connect a large capacitor or inductor it will not
register. This is for residential use. For commercial
use, they may have additional meters to measure reactive
power as well as peak demand (load).