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Article on Fluorescent Lamps and Ballasts
> From: "ian (i.b.) philips" <ianphil at bnr_ca>
> Date: Wed, 6 Dec 1995 11:54:00 -0500
> Subject: Article on Fluorescent Lamps and Ballasts
Ian,
> In the meantime, the editor had a question: "Why are T
> lamps brighter than equivalent T12s?". This assumes that one alr
> accepts that they are (is this generally accepted?). Can anyone
> out here?
All you need do is look at the lumen ratings for the bulbs in
question. As long as T-8s are used with the proper ballast, they
_are_ brighter... and they are _much_ brighter on a per watt
basis.
> ================================================================
> The bottom line is
> people prefer:
> T8 bulbs in combination with an
> Electronic rapid start ballast.
I'm not sure it's accurate to say that "people prefer" these
lights. I have yet to talk to anyone who has tried them who
doesn't prefer them, but at this point, at least in the U.S.
T-12's are in the majority, just because it's the (outdated)
industry standard. It also must be made clear that not any old
T-8 will do. There are as many variations of T-8's as there are
T-12's.
>
> The benefits being:
> More light for the same number of bulbs.
> Longer bulb life with lower lumens drop off.
> Significant power ($) savings.
Add that the bulbs are _much_ cheaper than comparable T-12 bulbs
as well!
> Douglas Bardell reported that on 26 May 1995 he installed 4 x 40
> fluorescent tubes over his aquarium. His hour meter read 1786 an
> to his Sekonic Lux meter the light measured 2200 lux. The next t
> checked, the hour meter was 3879 (about 168 days, a little less
> hours per day) and the lux meter read 1700. A loss of nearly 25%
Unless Dougs first measurements were made _after_ the initial 100
hour "burn-in" period, he was getting an artificially high reading
for that first measurement. The initial lumen ratings for these
bulbs are _after_ burn-in.
> Karen Randall reported a conversation with a lighting specialist
> that the kind of lumen drop-off George Booth observed on the Tri
> Triluxes is to be expected if the bulbs are used without an elec
> ballast. (ed note: from all that I have read from George, I'd be
> if George didn't use electronic ballasts).
Why don't you ask George directly?
> Some people are suspicious of the lumen depreciation because the
> commercial places replacing their banks of lights every six to t
> The reply to this was that the human eye is a very poor judge of
> As long as the ambient light level is adequate for whatever acti
> taking place, the lighting is "fine". Most homes or offices don'
> bulbs until they burn out or start to flicker.
I believe most commercial installations do planned regular bulb
replacements based on the avergae expected lifespan of the bulbs.
They call this process "relamping".
> Karen Randell
Karen Randall<g>
> believes number 4 can be a big factor.
That might be a bit strong. I was reporting from industry
information I had in hand. I doubt many aquarists operate their
lamps on short starts. (although I know a few do the
"thunderstorm" bit.
> Sources in Ottawa
> There are a number of specialty lighting stores in Ottawa that s
> ballasts and lamps. If you phone around you will find that you c
> T8 rapid start electronic ballasts by Advance (Philips) for 2-tu
> about $30 and for 4-tubes for about $40. Places selling these in
> Buchanan, Marchand, and Litemor.
You might want to look around a bit more. I haven't purchased 4
bulb ballasts, but my 2 bulb ballasts run me about $16 a piece.
> I myself am in the process of building a hood for my 48 gallon t
> (13 x 48 inches), thus the reason for my interest in the subject
> The hood is finished, it just needs the electronics and reflecto
> on putting in four T8s powered by a single remotely located elec
> ballast. Perhaps this hood might be the subject of a future arti
You might also want to mention that it is a fairly simple job to
convert a standard aquarium fixture (or shop light, for that
matter) into a T-8 fixture. The end caps are the same, so it is
just a matter of removing the old ballast and replacing it with
the new one.
Karen Randall
Aquatic Gardeners Assoc.
Boston, MA