[Amps] Right mounting of HV oilfilled C's?

[Thomas Hoeppe]

Hello Peter and Arne!

I am afraid you are right! I replaced the damaged capacitor by the 3rd one I bought. Then I placed a mA meter from the rectifier to the capacitors. 
1. The current is slightly more then expected from the bleeders.
2. The current is "unstable".....mooving up and down for about 2 mA. Not a good sign...
3. The replaced capacitor is getting warm a bit. Not much, but more then the "survived".

I expect the next bang. I think I will add a fuse between rectifier and capacitor, too.

Thanks for your help! I always thought those oilfilled are the best choice!

Tom, DJ5RE


  ----- Original Message ----- 
  From: peter.chadwick at Zarlink.Com 
  To: Thomas Hoeppe 
  Cc: Karl-Arne Markström 
  Sent: Monday, January 04, 2010 12:46 PM
  Subject: Re: [Amps] Right mounting of HV oilfilled C's?



  Thomas, 

  As Karl-Arne says, this type of capacitor isn't designed for high ripple current, just low duty cycle high pulse current. The same applied to the old 'photoflood' electrolytics meant for flashlight photography. 

  If used in a tuned choke input application, where the peak ripple current is much reduced, they might do the job. But in a capacitor input  filter, I would expect a very short life before they go bang! 

  The big, old fashioned oil filled paper capacitors from the 1950's could be mounted anyway you wanted. 

  Back to the computer grade electrolytics...... 

  Happy New Year 

  vy 73 

  Peter G3RZP 



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