[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Overdriving F32 lamps, lumen outputs
I just tested some 4' 32 watt lamps on a 4 x 32 watt ballast with a high
quality light meter. I made a box that fits over the test lamp to block
any outside light and tested several setups. By comparing the Lux
readings to the known ballast factor of the ballast I could "calibrate"
my device so I could calculate the lumen output each lamp. There is a
lot of data so I am just posting a few of the interesting setups.
4 F32 lamps, 1 lamp/circuit, 1 ballast output/circuit: 2424 lumens/lamp,
9696 lumens total, 93 lumens /ballast watt
2 F32 lamps, 2 lamps/circuit, 1 ballast output/circuit: 4115
lumens/lamp, 8230 lumens total, 89 lumens/ballast watt
1 F32 lamp, 1 lamp/circuit, 4 ballast outputs/circuit: 5735 lumens/lamp,
5735 lumens total, 79 lumens/ballast watt
I have quite a bit of confidence in this data but I wouldn't take it too
seriously. I am sure it is no more accurate than plus or minus 5% and
maybe worse than that. The lumen measurements are quite repeatable but
it makes a difference when you measure the lamp as the temperature of
the lamp alters the current and lumen output of the lamp.
The 4x overdriven lamp gets very hot which can't be good for it. Notice
that this lamp produces more light than a 55 watt PC. The pair of 2x
overdriven lamps produce more light than a 96 watt PC.
I am still trying to determine how to test and compare T12 lamps with T8
lamps. When I use my device to measure a different diameter lamp, I have
to "recalibrate" my device. I do not have a ballast that would be good
to use as a reference. I would prefer an electronic ballast and I only
have a magnetic one. However assuming that T12 lamps act in a similar
way when overdriven, don't expect similar large increases in lumen
output when overdriving F40 lamps.
This data is very suprising. The loss in lumen efficiency is not that
significant when you consider the large potential for increases in
fixture efficiency. A good reflector and you have a really great and
inexpensive light fixture. Personally, I would stay away from 4x
overdriving. 2x overdriving will provide plenty of light in a small
space, gives you lots of light per ballast, won't overheat the lamp
nearly as much and just seems like a safer bet overall. Afterall, these
ballasts were not designed to do this and there may be some danger