BulbCollector Forums
BULB DISCUSSION BOARDS => Antique Bulb Discussion => Topic started by: Fletch on April 06, 2010, 12:43:39 pm
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Hi, I acquired this cool looking Bulb is a Siemens 51 "Gas Filled" 170v 2000w.
Its 7" wide and 16" high. I was wondering what it was used for?
Light House?, Movie Projector?
Note: Its a screw-in bulb and its sitting in a plexi base.
Thanks in advance
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Hi Fletch,
i have seen a similar bulb, it was in an old theatre spotlight from the 40s or 50s.
A bit strange is the voltage rating with 170V.
BR
Frank
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Thanks, it is actually 110v after examining it again. Its hard to read as the brass is tarnished.
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A few years ago i fond a Spotlight with a similar bulb from RADIUM on the thrash. This bulb had only 1000W and a Voltage of 220V. The fixture was turnable so you can put the internal Reflector on the right place. Unfortunally i have sold that spotlight at ebay an i have no photos of that.
BR
Frank
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This is undoubtedly an episcopic lamp for Fresnel projectors used in TV/movie/photographic studios, as also in theaters and almost in any kind of scenic uses. It has an internal evaporated reflecting layer in the shape of a spherical cap that directs the light emmited by the grid-shaped filament to the front of the globe towards the stepped lens. The lamp itself when fixed to the lampholder, can be moved forward and backward respect to the Fresnel lens to make diverge, collimate or converge the output beam.
Most common power ranges of such lamps are 500, 1000, and 2000 w.
When I was a photography student I often used these Fresnels to get some special effects (side lighting, backlight, concentrated or spot lighting) in portrait, mainly when taking pictures in B/W.
Today, Fresnel projectors are fitted with halogen lamps, which as a drawback, needs of an external mirror to concentrate the light against the lens. Also, some Fresnels uses HID lamps too, especially when a high colour temperature (?K) value is needed and a high efficiency is desirable.
Regards