[pure-silver] Re: Enlarger Lamp Life

I think there is an AC capacitor in parallel to one of the windings, fiddling 
with the value changes the regulated output voltage. It was a long time ago 
that I played around with CSV transformer.
Richard might know more about them
My preference is a regulated  117 V DC. But there is catch in using DC to feed 
lamps, the filament burns only in one side. The Beseler enlarger uses a 82v 
lamp, it is easier to regulate 117v to 82v. In my hook up I used a transformer 
that delivers at least 170v ACx 5A, very heavy. Now someone could build a 
regulated switching power supply weighing a pound and delivering 600w, that's 
the power computer PS uses.

Jacques


----- Original Message ----- 
  From: Nicholas O. Lindan 
  To: pure-silver@xxxxxxxxxxxxx 
  Sent: Monday, October 27, 2008 10:09 PM
  Subject: [pure-silver] Re: Enlarger Lamp Life


  "Richard Knoppow" <dickburk@xxxxxxxxxxxxx>

  > One virtue of a CSV is that the output shuts down 
  > completely if its shorted.

  They don't really shut down, they deliver a constant
  current when they are shorted are quite content to
  deliver this current forever.

  A foible of CV transformers is they draw the same power
  from the AC line no matter what: a 500W transformer will
  draw 500 watts with no load, with a 500 watt load or with
  a dead short across it's output.

  I was filing a patent with the same attorney who represented
  Sola (the largest maker of CV transformers), we got to talking
  about CV's and it was his opinion that no one at Sola, or
  anywhere else for that matter, really understood how they worked.

  --
  Nicholas O. Lindan
  Cleveland Engineering Design, LLC
  Cleveland, Ohio 44121

  
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