Second question--is more of a "myth" question.. The HPL575's used in S-4's that are listed at 115v, is it true that to get the output(lumens), the lamps are deliberately made at strictly 115v (instead of 120v) to overtax them when run at 120v, for extra brightness?
Yes it’s true that most of the high output dichroic lamps are designed to operate over voltage. You can get 120v versions of these lamps especially in the HPL series, but yuck - it’s brown. Think about voltage loss from the dimmers and voltage drop to the fixture. Meter your fixture and see what your actual power is. It’s probably going to be in the range of 117v. Now consider this data: Volts - A measurement of the electromotive force in an electrical circuit or device expressed in volts. Voltage can be thought of as being analogous to the pressure in a waterline. The effect of voltage on a lamp will cause a significant change in lamp performance. For any particular lamp, light output varies by a factor of 3.6 times and life varies inversely by a factor of 12 times any percentage variation in supply. For every 1% change in supply voltage light output will rise by 3.6% and lamp life will be reduced by 12%. This applies to both DC and AC current. Most standard line voltage lamps are offered at 130v. Since most line voltage power is applied at 120volts, the result is a slight under voltaging of the filament. The effect of this is substantially enhanced lifehours, protection from voltage spikes and energy cost savings.
Voltage and Light Output: The effect of voltage on the light output of a lamp is ±1% voltage over the rated amount stamped on the lamp, gives 3.1/2% more light or Lumens output but decreases the life by 73% and vise a versa.
Do not operate quartz Projection lamps at over 110% of their design voltage as rupture might occur. GE Projection, Ibid p.13
It also has an effect on color temperature, just have not logged it into my notes yet. Basically, as the voltage goes up, color temperature follows to a small percentage. Thus in addition to the higher starting color temperature of dichroic halogen/xenon lamps, they operate at an even higher appairent brightness or more blue light than a normal halogen lamp.
Just curious...always interested in another opinion that could be helpful.
If it were not for the fact that I'm constantly building upon my notes and adding lamp data, I would say the notes might be interesting. Very long but interesting to post in full. Really long. Anyway does this help? More questions?
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