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Author Topic: What's the purpose of the chain hanging from a Xenon bulb? Brad Allen Jedi Master Film Handler Posts: 688 From: Evansville, IN, USA Registered: May 2000 posted 11-21-2005 01:27 AM                     Subject says it, my kneisley's is the only one's I've seen this in. What is the point of the chain. I've always just blindly put it back on when changing a bulb.  |  IP: Logged Richard Hamilton Phenomenal Film Handler Posts: 1341 From: Evansville, Indiana Registered: Jan 2000 posted 11-21-2005 06:19 AM                     quote: Brad Allen I've always just blindly put it back on when changing a bulb. Does that mean you keep your eyes shut when you change bulbs?  |  IP: Logged Marin Zorica Jedi Master Film Handler Posts: 671 From: Biograd na Moru, Croatia Registered: May 2003 posted 11-21-2005 08:04 AM                     Can you described little more about that "chain", maybee is volfram wire for faster ionization of xenon gas you thinking on?  |  IP: Logged Gilbert Travin Expert Film Handler Posts: 101 From: Villeurbanne / France Registered: Jan 2004 posted 11-21-2005 08:17 AM                        I think Martin is right : this "wire" facilitates bulb ignition. Even cold, there is high pressure xenon into the bulb >>> danger !!! Use the protection mask and gloves !!!  |  IP: Logged Gordon McLeod Film God Posts: 9532 From: Toronto Ontario Canada Registered: Jun 99 posted 11-21-2005 08:36 AM                     At one point kniesly felt it helped eliminate a capacitive effect in the lamp during ignition  |  IP: Logged Brad Allen Jedi Master Film Handler Posts: 688 From: Evansville, IN, USA Registered: May 2000 posted 11-21-2005 12:54 PM                     Sure Richard, I've performed it so many times I can do it with my eyes closed. It's a ball chain, just like the type you would find on a light pull chain.  |  IP: Logged Frank Angel Film God Posts: 5305 From: Brooklyn NY USA Registered: Dec 1999 posted 11-22-2005 05:13 AM                        quote: Gordon McLeod At one point kniesly felt it helped eliminate a capacitive effect in the lamp during ignition Does it?  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 11-22-2005 05:43 AM                        With the nichrome "gimmick capacitor" wire tied to every xenon bulb, it is probably no longer needed. Just a vestige from former times. As regards the old Kneisley; another trick is to insulate the bottom of the igniter from the case using plexi or fibreglass. Arc overs there are common when the igniter fires. It still arcs in the bulb, but intensity is reduced. This is a lamp that can be made to run very well enough, but it takes a bit of labor to do so. Whenever we sell one used, we replace the meter, shunt, capacitors in the power supply, add the igniter spacer and upgrade the teflon bushing. I would never sell one "as is." Louis  |  IP: Logged Marin Zorica Jedi Master Film Handler Posts: 671 From: Biograd na Moru, Croatia Registered: May 2003 posted 11-22-2005 11:59 AM                     Louis, i think is wolfram wire on osram bulb's, i know because on poster i got with bulb it says wolfram! Maybe chain is for bulb arc stabilization like on carbon arc systems. Can you upload picture of it?  |  IP: Logged Brad Allen Jedi Master Film Handler Posts: 688 From: Evansville, IN, USA Registered: May 2000 posted 11-22-2005 01:16 PM                     Marin, I will get a picture as soon as I can remember to take the camera along. Louis, or anyone else, is there a reason one couldn't just by- pass the shunt all together and take it out of the loop? I use a DC clamp on meter for amp adjustments anyway. Interesting about the plexi addition, any thickness will do I assume? And I assume the placement of the plexi is to be between the bottom of where the entire Telsa coil assembly meets the metal case?  |  IP: Logged Louis Bornwasser Film God Posts: 4441 From: prospect ky usa Registered: Mar 2005 posted 11-22-2005 03:15 PM                        yep  |  IP: Logged Richard Fowler Film God Posts: 2392 From: Ft. Lauderdale, FL, USA Registered: Jun 2001 posted 11-22-2005 03:56 PM                     White plexi or Phenolic board does the trick which stands up to the U.V. from the bulb and is more flame resistant. The front bulb support has an insulator that deteriorate with age which should be checked.  |  IP: Logged Frank Angel Film God Posts: 5305 From: Brooklyn NY USA Registered: Dec 1999 posted 11-22-2005 08:03 PM                        quote: Brad Allen It's a ball chain, just like the type you would find on a light pull chain. That's Kneisley's emergency igniter....if the bulb fails to lite, you just pull the chain to turn it on. (Sorry, I couldn't resist).  |  IP: Logged Brad Allen Jedi Master Film Handler Posts: 688 From: Evansville, IN, USA Registered: May 2000 posted 11-24-2005 01:13 PM                     The chain....  |  IP: Logged Tim Reed Better Projection Pays Posts: 5246 From: Northampton, PA Registered: Sep 1999 posted 11-24-2005 01:38 PM                       What Gordon said.  |  IP: Logged

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