Article View: sci.electronics
Article #3766Re: Fluorescent light ballasts
From: Larry Lippman
Date: Sat, 18 Nov 1989 05:10
Date: Sat, 18 Nov 1989 05:10
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2684 bytes
In article <4995@ae.sei.cmu.edu>, rsd@sei.cmu.edu (Richard S D'Ippolito) writes:
> In article <22334@gryphon.COM> richard@gryphon.COM (Richard Sexton) writes:
> =There are two kinds of ballasts: magnetic and elecronic. The
> =former is by far the most common type, and is little more than
> =a transformer.
The primary purpose of a ballast is for current limiting, and it
therefore functions as a saturable inductor and not a transformer. The
simplest ballast is merely a series inductor. Depending upon the size,
wattage and operating voltage of the lamps, a ballast may also function
as an auto-transfomer for increased voltage at the time of starting ONLY;
once the lamp fires, the voltage is then LESS than the AC line.
> = It is cheap to puchase. It has the drawbacks
> =of being noisy (this is the source of the humm, or buzzing
> =so often ascociated with fluorescent lights) and not
> =terribly energt [sic] efficient. A fixture with two 40 watt bulbs
> =may actually draw 250 watts.
Utter nonsense!
> Twentyfive years ago, when I did lighting design, the typical transformer
> ballasts for two 40W tubes consumed less than 20W, making the total fixture
> demand less than 100W. I know this because I also had to calculate the
> air-conditioning load.
>
> What are you talking about?! Is this some hype from an electronic ballast
> manufacturer?
Richard Sexton's comments are bogus, and I suspect he is suffering
from a case of the bends as a result of being immersed in his sci.aquaria
fiasco for too long.
In any event, Richard D'Ippolito is quite correct. Fluorescent
lamps are quite efficient with respect to ballast losses, having a range
of 20% loss at worse case and 95% loss at best.
Therefore, a 2-lamp 40-watt fixture of say, a rapid-start variety
will consume no more than 100 watts of energy when operated at rated
voltage.
<> Larry Lippman @ Recognition Research Corp. - Uniquex Corp. - Viatran Corp.
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Path: arc1-ca.pugleaf.net!utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!tut.cis.ohio-state.edu!ucbvax!hplabs!kitty!larry From: larry@kitty.UUCP (Larry Lippman) Newsgroups: sci.electronics Subject: Re: Fluorescent light ballasts Summary: Efficiency of fluorescent lamps... Keywords: advance Message-ID: <3504@kitty.UUCP> Date: 18 Nov 89 05:10:22 GMT References: <22334@gryphon.COM> <4995@ae.sei.cmu.edu> Organization: Recognition Research Corp., Clarence, NY Lines: 45