Re: T8 benefits

["S. Hieber" <shieber at yahoo_com>]

Wayne Jones said:
"> NO T5s are inherently more efficient than HO T5s just like all NO
> lamps
> compared to their HO counterparts. 

I stand corrected.  I was under the distinct impression that those 8"
and 12" buggers were rather inefficient as flourescents go -- but that
could be just a matter of 3-5 watts of ballast heat equaling about 1/3
to 1/2 of the lamp energy.


> They did not have high frequency ballasts at the time that VHO lamps
> were developed. It appears that an NO lamp operating at a high
> frequency
> can be overdriven with much less loss in efficiency than on a
> magnetic
> ballast. 

The wonders of high frequencies and better bulbs too.  Even if they new
that high freqs had so many benefits, electronic ballasts would have
had to wait for advances in solid state devices.  They didn't MOSFETs
back then, which now make high-power driver circuits so inexpensive. 
Bipolar transistors were pretty new then, too.

The issue with overdriving wasn't/isn't that it cannot be done, it's
just that the energy efficiency generally decreases as you up the
wattage.  (I still think there are perhaps some odd exceptions with
ballasts that waste a huge proportion of energy relative to the lamp
but the general point is of greater interest for aquaria, anyhow).  To
make marketable fluorescent bulbs that ran at high wattage required
improving the high wattage efficiency -- not improving it to what the
lower wattage efficiency is, but something better than the 1:5 ratio
the first bulbs had when driven at high wattage.  (And, of course, the
comparisons must be between the best performers.  Compared to a sort of
mediocre or crappy bulb, lots of other bulbs will outperform, even at
higher wattage.)

I think you hit it on the head that electronic ballasts can make any
NOs perform better than old style mag ballasts at higher power.  Not
every electronic ballast is right for every bulb *but* an electronic
ballast can be made for any bulb that will make it perform brighter
with less energy loss than the best mag ballast.  And the ballast
needn't be expensive due to technology or parts costs.

The circuits I have seen are so basic, and the parts so inexpensive,
(especially now that the key elements have been incorporated onto
integrated chips) that electronic ballasts out to drive mag ballasts
out of the market just on price alone.  But that won't happen until we
stop paying $150 or so for ballasts when great ones can be had $10 or
$20 dollars.

You're the only one on this list testing this stuff avidly, so we await
your future posts.

Scott H.

Scott H.


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