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From: jans@stalker.gwd.tek.com (Jan Steinman)
Newsgroups: sci.electronics
Subject: Re: Power Factor Controller
Message-ID: <8478@tekecs.TEK.COM>
Date: Mon, 4-May-87 15:36:54 EDT
Article-I.D.: tekecs.8478
Posted: Mon May  4 15:36:54 1987
Date-Received: Wed, 6-May-87 01:05:49 EDT
References: <278@lpi.UUCP> <7988@utzoo.UUCP>
Sender: nobody@tekecs.TEK.COM
Reply-To: jans@stalker.UUCP (Jan Steinman)
Organization: Tektronix, Inc., Wilsonville, OR
Lines: 29

In article <7988@utzoo.UUCP> henry@utzoo.UUCP (Henry Spencer) writes:
>> What types of devices/motors are (power factor controllers) suitable for...
>

>.. the only situation power-factor controllers help with is motors that run
>for substantial periods at less than full power.  Things like refrigerators,
>which vary their output by cycling on and off rather than by running at lower
>output continuously, don't benefit at all.  My impression is that power-factor
>controllers are really of very limited use to consumers, since few motorized
>consumer products run at partial power for long.

A substantial portion of a "continuous duty" motor's capacitiy is used for
starting it.  Motors that must start at full load still present some reactance
to the line.

My experience is that PFC's can save 8% to 15% on older refrigerators and
freezers, but late model ones have PFC's built into theier compressor motors.
A refrigerator that burns $100 a year (not uncommon in high-rate areas, or with
older motors) can then payback a $29.95 PFC in as little as two years.

Henry's right, though.  Where they really payback are on variable-load devices.
Power tools and washing machines com immediately to mind.  I've seen older
washers save 30%.  A table saw or drill press runs at nearly 50% without load.

My dad sells PFC's, and I've got several in use.

:::::: Software  Productivity  Technologies   ---   Smalltalk   Project ::::::
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