VigIIPeaBurner wrote:I noticed the voltage is also rated at 130. My father, a retired electrician, always ordered 130v bulbs for locations that were prone to burnouts or hard to reach outdoor spot lights. Rough service, IIRC, is another build criteria (filiment suport) from 130v. He told me the 130v bulb's filament wasn't stressed by running at maximum design voltage and there'd be less heat stress on it but there would be slightly less than the rated lumen produced.
The 130v bulbs were often special ordered at the supply store. Last year when I was replacing some exterior motion detectors located two stories up I noticed that Lowe's had 90 W 130v Halogen spots available in a bulk pack. I picked up a pack and they're working after 22 months. For the last ten years I could barely get a year of service from any brand 120v halogen spots I could find. Dad use to prefer Philips bulbs for their long life but even the Philips spots I bought at the box stores didn't last any longer than the other brands.
For a supply voltage V near the rated voltage of the lamp:
Light output is approximately proportional to V raised to the 3.4 power.
Lifetime is approximately proportional to V raised to the −16 power.
So for example you could have a very, very long life by using a 220 volt bulb on 120, but you wouldn't have much light output. It's all about design parameters and what goal you are trying to achieve. Standard bulbs are designed for 1000 hours lifetime.
Lot's more information here:http://en.wikipedia.org/wiki/Incandescent_light_bulb