This is topic high exciter lamp voltage in forum Film Handlers' Forum at Film-Tech Forum ARCHIVE.


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Posted by Ed Inman (Member # 2583) on 09-15-2004, 08:39 PM:
 
I read in the archives where it's generally recommended to run DC exciter current a little below the rated voltage of the standard 9V/4A or 10V/5A exciter lamps. OK, here's my problem. The ancient 9V voltage transformer that was running my exciter lamp burned out yesterday and the only thing I could find locally with enough amps is a 13 volt, 10 amp DC power supply.

I hooked it up to a 10V/5A lamp and aside from burning a little brighter and hotter I can't see any major problem yet. With a slight EQ adjustment the sound still is clear and nice.

I'm also not terribly worried about shortening the life of the bulb a little since I'm obviously going to be forced to buy some of those red doo-dads next year anyway. But I'm just wondering if there is anything else I should be worried about. Is my exciter lamp going to explode or anything (LOL)?

Ed
 

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Posted by Mark Gulbrandsen (Member # 72) on 09-15-2004, 08:47 PM:
 
Ed, You shouldn't have any trouble finding a good used exciter supply for next to nothing or even for free.... since the advent of Steve Guttags favorite RED LED reader kits there are now tens of thousands of exciter supplys floating around helplessly in booths all across the country that will never be put to use again.
What you do want is a DC regulated supply. Run the lamp at about 80% of rated voltage. When funds allow get ONE OF Guttags favorite RED LED reverse scan kits and benefit from a huge improvement in sound quality.

Mark @ CLACO
 

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Posted by John Pytlak (Member # 331) on 09-15-2004, 09:39 PM:
 
You can estimate the change in rated life of a tungsten lamp operated at something other than its rated voltage:

http://www.eaoswitch.com/about/lamps.htm

http://vsg.cape.com/~pbaum/halogen.htm

quote:

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Rule of Thumb: a +5% increase in voltage results in

50% decrease in lamp life
15% increase in luminous flux
8% increase in power
3% increase in current
2% increase in color temperature

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