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From: king@kestrel.UUCP
Newsgroups: net.consumers,net.sci
Subject: Re: lightbulbs
Message-ID: <8430@kestrel.ARPA>
Date: Sat, 24-May-86 16:47:56 EDT
Article-I.D.: kestrel.8430
Posted: Sat May 24 16:47:56 1986
Date-Received: Mon, 26-May-86 01:37:45 EDT
Organization: Kestrel Institute, Palo Alto, CA
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Xref: watmath net.consumers:5348 net.sci:950


   From: timothym@tekigm2.UUCP (Timothy D Margeson) Newsgroups:
   net.consumers,net.sci Date: 22 May 86 19:40:27 GMT Reply-To:
   timothym@tekigm2.UUCP (Timothy D Margeson)

   Hi,

   About lightbulbs - Has anyone else besides me measured their line
   voltage that comes into their house?  I measured mine after several
   of my lights blew, were replaced then blew again in what seemed an
   abnormally short period of time. My measurment turned up a nominal
   voltage of 127.5 volts RMS (with a true RMS DVM made by Beckman). I
   called the power company, Portland General Electric, and I got the
   reponse "This is the normal voltage we set the lines to, to avoid
   the chance of brown-outs in the winter time."

   I just had to ask myself if PGE's motives were more pocketbook
   oriented. Quick calculations say that power usage will increase as
   the square of the voltage.  What this means is that a lamp rated at
   120 volts (when a common line voltage used to be 117 volts RMS) is
   being run at 127 volts, thereby reducing its life expectantcy to
   approximately 65 to 76 percent of normal (That's right folks, a 5
   percent increase in lamp voltage results in 20 percent increase in
   light out put and a 30 percent decrease in lamp life).

Suspicion is often healthy, but I think misplaced in this case.  An
increase in house voltage will not increase power consumption
significantly in the long run.  Induction motors usually consume no
more power at a slightly higher voltage than at their nominal (the
power factor decreases) and if they do, they are undersized and they
put out more power than with the nominal voltage, making (eg.) your
refrigerator turn off sooner.  Thermostatically controlled heating
devices consume no more power at the higher voltage.  Flourescant
light bulbs consume no more power (again, the power factor decreases).
Even incandescant light bulbs will consume no more power at the higher
voltage, because PG&E's customers will find themselves installing
smaller bulbs.  Consumers will run non-thermostatic heating devices
such as broilers for a shorter time.

Electronic devices might consume a bit more power depending on power
supply design.


   -- Tim Margeson (206)253-5240 tektronix!tekigm2!timothym @@ 'Who
   said that?'  PO Box 3500 d/s C1-937 Vancouver, WA. 98665