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From: whit@milton.u.washington.edu (John Whitmore)
Newsgroups: sci.electronics
Subject: Re: Dimming Fluorescent Lamps
Message-ID: <16828@milton.u.washington.edu>
Date: 20 Feb 91 22:42:33 GMT
References: <2688@beguine.UUCP>
Organization: University of Washington, Seattle
Lines: 26

In article <2688@beguine.UUCP> uchuck@uncmed.med.unc.edu () writes:
>We have a problem that maybe some of you may have run across and have
>solved before.  We have a lecture hall that has some 24 fixtures of the 4
>x 48 inch, 40 watt fluorescent lamps.  These require dimming to varying
>degrees depending on the format and subject matter being taught.
>Heretofore we have been using a special dimming ballast which will service
>4 of the fixtures at a time.  We are down to zero spares and the
>manufacturer does not sell these anymore ...

	You should ask an architect or mechanical engineer (after all,
that's who'd normally specify such an item for new construction) to
check for suppliers of dimmers for fluorescent lamps.

	Failing that, you could install standard fluorescent lamps on
four circuits; switch one turns on four tubes, switch two turns on
eight, switch three turns on sixteen, and switch four turns on
thirty-two.  It's primitive, but it'd give you some control.

	I may be mistaken, but I thought fluorescent lamp dimmers
were relatively simple items, just had a different turn-on phase for
the SCR; such an item wouldn't work right on incandescent bulbs
(and an incandescent dimmer would burn up if connected to a 
fluorescent fixture).  Although a home fix-it store wouldn't
carry such specialized items, probably a builder's hardware store would.

	John Whitmore


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