[Amps] Using an oil capacitor

[Mitch Cox]

Yours does not sound like a photo-flash or pulse rated capacitor. You should be good to go with that one. All of the conversation so far has been about pulse rated as opposed to capacitors like yours that is rated for continuous service.
  ----- Original Message ----- 
  From: Pete Raymond 
  To: Vic K2VCO ; Paul Kraemer 
  Cc: Amps reflector 
  Sent: Sunday, June 19, 2011 4:12 PM
  Subject: Re: [Amps] Using an oil capacitor


  I have been following this thread with some concern.  My oil filled 
  capacitor measures
  4 3/4" X 4 1/2" X 9 1/4", its markings are as follows.  General Electric, 
  Capacitor, Made in U.S.A.,
  25F492, 25uf at 4000 VDC.  How can one tell if this capacitor is suitable 
  for a HV power supply.
  73 Pete, N4KW

  ----- Original Message ----- 
  From: "Vic K2VCO" <vic at rakefet.com>
  To: "Paul Kraemer" <elespe at lisco.com>
  Cc: "Amps reflector" <amps at contesting.com>
  Sent: Sunday, June 19, 2011 1:34 PM
  Subject: Re: [Amps] Using an oil capacitor


  > Several respondents to my message have said the same thing. This capacitor 
  > cannot be used
  > at its voltage rating in filter service and needs to be de-rated to about 
  > half its spec'd
  > voltage in that case.
  >
  > I actually have two of these, so I could probably use them in series for a 
  > 26.5 uf filter
  > capacitor. This would be adequate for a cw transmitter, although I'm not 
  > sure if 6% ripple
  > wouldn't be audible on SSB. However, two capacitors make a very big 
  > package, so I'm
  > thinking about going back to the conventional string of electrolytics.
  >
  > Any recommendations for a source of electrolytics? There are lots of 
  > inexpensive ones on
  > ebay, but who knows if they are factory rejects!
  >
  > On 6/19/2011 10:10 AM, Paul Kraemer wrote:
  >> Vic BE CAREFUL. BE VERY CAREFUL!!!
  >>  From the size and capacitance you describe it is probably an "energy 
  >> storage capacitor"
  >> which is not suitable for power supply filter at even it's published 
  >> ratings. You will be
  >> picking pieces of capacitor out of places you really don't want them.
  >> Paul K0UYA
  >>
  >> ----- Original Message ----- From: "Vic K2VCO" <vic at rakefet.com>
  >> To: "Amps reflector" <amps at contesting.com>
  >> Sent: Sunday, June 19, 2011 12:59 AM
  >> Subject: [Amps] Using an oil capacitor
  >>
  >>
  >>> I have an oil capacitor rated at 53 uf 3.5kv. I would like to use it in 
  >>> a power supply
  >>> with a transformer delivering 2.4 kVAC. The peak voltage is thus close 
  >>> to 3400V.
  >>>
  >>> I've never used an oil capacitor before. My line voltage is pretty 
  >>> constant at 240V, but
  >>> if it were to rise to 250V, the voltage rating of the capacitor would be 
  >>> exceeded. What
  >>> kind of safety factor do capacitors like this have?
  >>>
  >>> The capacitor is 4-1/2" x 4" x 10" and is marked CSI 4W308T. The CSI 
  >>> website
  >>> <http://www.csicapacitors.com/csite/cms/149.htm> doesn't list this 
  >>> particular one, but
  >>> other 3.5kV capacitors have similar part numbers. There's no detailed 
  >>> spec. There is this
  >>> statement:
  >>>
  >>> "The WM series of capacitors is designed for general purpose pulse 
  >>> applications in power
  >>> supplies for lasers, flash tubes and other capacitor discharge circuits 
  >>> where moderate to
  >>> long life is required."
  >>>
  >>> I'm not sure if this is appropriate for power supply filter application. 
  >>> Anybody familiar
  >>> with these?
  >>> --
  >>> Vic, K2VCO
  >>> Fresno CA
  >>> http://www.qsl.net/k2vco/
  >>> _______________________________________________
  >>> Amps mailing list
  >>> Amps at contesting.com
  >>> http://lists.contesting.com/mailman/listinfo/amps
  >>
  >
  > -- 
  > Vic, K2VCO
  > Fresno CA
  > http://www.qsl.net/k2vco/
  > _______________________________________________
  > Amps mailing list
  > Amps at contesting.com
  > http://lists.contesting.com/mailman/listinfo/amps 

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