Right On Carl.
Chuck
W6RD
----- Original Message -----
From: "jeremy-ca" <km1h@jeremy.mv.com>
To: "Barrie Smith" <barrie@centric.net>; "Han Higasa"
<higasa@plum.ocn.ne.jp>; <amps@contesting.com>
Sent: Thursday, March 06, 2008 11:31 AM
Subject: Re: [Amps] Oil-caps delating 2/3 ratings?
> PLEASE, dont compare capacitors designed for HV PS use such as in amps, BC
> and similar with high ESR caps designed for various energy discharge
> applications.
>
> A true oil filled will pretty much last "almost forever" even when run at
> its ratings. I have several 40's thru 60's GE, Aerovox and similar in use
> here running very cool at close to their marked voltages. That is another
> benefit of those good old PCB's; they keep the heat down.
>
> I also have a 53 MF 5KV discharge cap in a compact 3200V at idle PS used
> for a UHF 1500W amp. It shows just a small amount of heat during contest
> operation.
>
> Carl
> KM1H
>
> ----- Original Message -----
> From: "Barrie Smith" <barrie@centric.net>
> To: "Han Higasa" <higasa@plum.ocn.ne.jp>; <amps@contesting.com>
> Sent: Thursday, March 06, 2008 1:02 PM
> Subject: Re: [Amps] Oil-caps delating 2/3 ratings?
>
>
>>
>>
>>
>>> Recently an old man told me that all of the caps are energy storage jobs
>>> and they are usually derated for continuous duty to about 2/3 rating.
>>> I thank him very much.
>>>
>>> I am using cheap 32uF 4500V GE non-pcb caps.
>>> Should I use it at 3000V maximum?
>>> Fortunately I am using this potential level now.
>>> If someone use 16uF 7500V Arioso caps like Henry,
>>> maximum working voltage should be 5000V?
>>>
>>> Would you please tell me the reason for the "2/3 derating"
>>> practically when using them for our linear amps?
>>>
>>> For a long time I had a question why GE had not indicate working
>>> voltage and test voltage but only "4500V".
>>>
>>> Additionally anyone did a destructive/non-destructive test on it?
>>> Seemingly they are sustainable at 5kV, but if the number 2/3 work
>>> their life should be very short.
>>
>> Han:
>>
>> Totally by accident I ran a pair of these caps at 6500 volts for several
>> minutes. Nothing bad happened.
>>
>> I still use that pair of caps in power supply that runs 4200 volts
>> no-load.
>>
>> As they say, YMMV.
>>
>> 73, Barrie, W7ALW
>>
>>
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>>
>
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