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Topic: Xenon Bulb wire

Frank Angel
Film God

Posts: 5305
From: Brooklyn NY USA
Registered: Dec 1999

posted 09-09-2007 02:48 PM

the Osram lamps that I've got, 4500W have no wire. They ignite fine. What's that about?

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Floyd Justin Newton
Jedi Master Film Handler

Posts: 559
From: Phoenix, Arizona, USA
Registered: Jun 2002

posted 09-09-2007 04:00 PM

I'll tell 'ya that's about, Frank. Are you holding the bulb with your bare hand when you ignite it??? Just kidding!

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John Hawkinson
Film God

Posts: 2273
From: Cambridge, MA, USA
Registered: Feb 2002

posted 09-09-2007 07:31 PM

quote: Osram's XBO Theatre Applications Guide

Ignition Wire

The ignition wire is a thin, thermostable iron-nickel wire slung from one lamp neck to the other and - depending on lamp type - sometimes continued as far as the base sleeve. Its existence makes igniting the lamp easier, especially when rectifiers and igniters have diminished in efficiency with increasing age. Its function is twofold: firstly it distorts the high-voltage electrical field applied to ignite the lamp, producing inhomogeneities which cause peaks in the field distribution, a condition favorable to sparkover. Secondly, partial discharges take place on it, these can knock electrons from the cathode by a photoelectric effect, and these in turn initiate the discharge

--jhawk

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Phil Hill
I love my cootie bug

Posts: 7595
From: Hollywood, CA USA
Registered: Mar 2000

posted 09-09-2007 07:41 PM

Thanks jhawk for posting all that gobbledegook... Mark and Louis said it BEST in their responses!

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Michael Schaffer
"Where is the
Boardwalk Hotel?"

Posts: 4143
From: Boston, MA
Registered: Apr 2002

posted 09-09-2007 08:19 PM

Actually I think what it says in the Osram text makes a lot of sense. That is what I had been asking: not what the "function" of the wire is, we all know that, but what its effects are from a physics point of view (so that one can "picture" what is going on). I don't quite understand yet how the photoelectric effect fits into "secondly" though.

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Frank Angel
Film God

Posts: 5305
From: Brooklyn NY USA
Registered: Dec 1999

posted 09-09-2007 10:33 PM

Yah, yah, yah, but these are Osram bulbs that I've got and they don't have any freakin wire. In fact, Osram has a video all bout how awesome their bulbs are and how they explode so nicely, and I listen very carefully to the pitch man and he definately says that the wire is on SOME bults. Could it be the wattage -- that the higher wattage bulbs don't need them as much? Ours are 4500w. I'm just guessing, based on the inhomogeneity peaks and phototronic metaphysical structure of the wadayacallit.

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 09-10-2007 09:06 AM

quote: Frank Angel
the Osram lamps that I've got, 4500W have no wire. They ignite fine. What's that about?

HA.... They might not ignite too well when you get some hours piled on them. Thats when things begin to get difficult with alot of lamps.

MAra

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Dave Macaulay
Film God

Posts: 2321
From: Toronto, Canada
Registered: Apr 2001

posted 09-10-2007 11:08 AM

I don't know how the wire would make any light, but there is a photoelectric effect on ionizing gases. It's common to see a neon light that won't work in the dark but "ignites" fine while a little external light hits it.

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Michael Schaffer
"Where is the
Boardwalk Hotel?"

Posts: 4143
From: Boston, MA
Registered: Apr 2002

posted 09-10-2007 03:41 PM

Maybe the wire glows briefly when high voltage is applied to the lamp (and maybe only in non-visible parts of the spectrum, but then none of us has ever actually looked at the wire and the lamp when they ignite), since "partial discharges" take place across it.

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Bill Enos
Film God

Posts: 2081
From: Richmond, Virginia, USA
Registered: Apr 2000

posted 09-11-2007 06:59 PM

It's done by PFM

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16657
From: Music City
Registered: Jun 99

posted 09-12-2007 08:40 AM

Bill.... I think you ment to say "its done by PMS".

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Bill Enos
Film God

Posts: 2081
From: Richmond, Virginia, USA
Registered: Apr 2000

posted 09-12-2007 12:21 PM

Pure F------G Magic

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