Date: Sat, 18 Apr 1998 11:25:44 +0100 From: "Adrian Arnold" <acarnold@acis.co.uk> To: cp@opus.hpl.hp.com Message-Id: <aabcdefg1305$foo@default> Subject: Re: Interesting answer on fixtures
> We recently got an answer to our fixture doubts by Haakan Murevaern
> <murevarn@algonet.se>.
> As I understand now, one of the main reasons for using fluorescent
> over incandescent bulbs is that the heat is mainly discipated by the
> ballast, which can be placed out of the fixture. But as Haakan says,
> in the case of these particular bulbs, the ballast is in the bulb
> itself, and then, I think, it remains INSIDE the fixture.
As I understand it, the newer small U shaped energy saving bulbs do not
have a ballast as such but have a small circuit with transformer/choke
arrangement which changes the usual 50 or 60Hz mains voltage to a much
higher frequency which is more efficient for this type of bulb - heat loss
is less and efficiency is better.
Long, traditional 'strip lights' have a ballast which dissipates some heat
but this can be mounted elsewhere, leaving the cool tube part to illuminate
the terrarium. They also have the advantage that the light is distributed
more evenly.
The bulbs I have state 1200lumens for 20W or 900lumens for 15W. The hottest
part of these bulbs is the tube and some makes seem rather more efficient
than others (though they all seem to consume more than the manufacturers
would have us believe!). Whatever system you use, you will have to get rid
of the heat and you can effectively consider that *all* of the power input
is heat.
Remember, BTW, that CPU fans are usually 12volt, not 220, and some power
supply fans are also 12V
Hope this helps.
Regards,
Adrian Arnold
acarnold@acis.co.uk
http://www.acis.co.uk/index.htm
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