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@rakefet.com>
To: "Paul Kraemer" <elespe@lisco.com>
Cc: "Amps reflector" <amps@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@rakefet.com>
>> To: "Amps reflector" <amps@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@contesting.com
>>> http://lists.contesting.com/mailman/listinfo/amps
>>
>
> --
> Vic, K2VCO
> Fresno CA
> http://www.qsl.net/k2vco/
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps
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