[Amps] Using an oil capacitor

Jim W7RY w7ry at inbox.com
Sun Jun 19 13:39:36 PDT 2011


This EBay item number has a large amount of info about it...  270766657819

73
Jim W7RY


--------------------------------------------------
From: "Mitch Cox" <ww4cox at embarqmail.com>
Sent: Sunday, June 19, 2011 1:28 PM
To: "Pete Raymond" <n4kwpete at centurylink.net>; "Vic K2VCO" 
<vic at rakefet.com>; "Paul Kraemer" <elespe at lisco.com>
Cc: "Amps reflector" <amps at contesting.com>
Subject: Re: [Amps] Using an oil capacitor

> 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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