At work we have several 480 volt HID lights we are giving away. I was
I have a 30x30 with no ceiling. (Other than rafters). The bottom of
the rafter is 10 feet 4 inches off the ground. (But I could mount a
light higher up on a rafter.
Would it be feasible to use some of these inside my garage/shop? How
hard/expensive is it to convert them?
I helped a friend of mine do just that. We put up 6x 400W metal halide
low bay fixtures in his 30x50 shop with a 14' ceiling. They too were
480V with single tap ballasts. We bought new multitap ballasts which I
believe were under $100 each and installed those. Do verify that your
existing ballasts are not multi tap, if they are, you can rewire them to
the correct voltage, but most in these things are not.
These things are about 70 lumens per watt, so similar to fluorescent in
efficiency, and likewise the heat output per watt will be similar.
They're nice, but do be careful. The wattage printed on the lamp is the
nominal rating the lamp is designed for. In actuality, the lamp operates
at a wattage determined by the ballast. It is *absolutely imperative*
that the lamp type is matched to what the ballast is designed for, and
it is also important to replace the lamp at the end of rated life,
usually around 20K hours rather than waiting for it to burn out
completely, often resulting in ballast damage or a so called
"non-passive" failure, in other words a violent rupture of the high
pressure arc tube, which will usually break the outer bulb and rain down
a shower of red hot quartz fragments. Special "protected" lamps are
available for use in open fixtures which contain a heavy quartz shroud
or wire shield wrapped around the arc tube to contain the blast.
Enclosed fixtures are designed to contain a failure of this nature, and
must always have all covers in place when operating.
"High Pressure" sodium lights in contrast actually operate below
atmospheric pressure so they lack the explosion risk but they produce
that yucky orange light with terrible color rendering. You don't want
those in your shop. Either way, use them correctly and they are no
problem at all. Good dependable light source with high efficiency and
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