I have been using
this light fixture for quite some time with a 150W HPS lamp. However, the ballast is probably a 100W ballast. What happens to an HPS lamp after running it like this for a while?
My guess is that the life is decreased, because as the sodium escapes the arc tube, the voltage of the lamp rises to a point where the fixture cannot sustain an arc. I imagine that the voltage is lower with smaller lamps, so the voltage would more quickly go outside of the acceptable range.
