Hi Carl and Igor,
Why such a mess?
This insistance on using electrolytic caps in such quantities puzzles me?
HENRY uses a single 16UF @ 8KV oil filled and is available for $125 (new).
This is less than the computer caps in the quanties needed and is superior.
Probably smaller too.
No equalizing resistors or worry about matched units. No concern about how
much current to draw through series devices or cooling.
There are virtually no disadvantages to oil over electrolytics.
Igor, it sounds like you're making a "real" amp. Most manufacturers use
computer caps because at lower voltages they are cheaper in the toy desktop
models.
Your real amp voltages require a real capacitor.
Oil filled caps are not too expensive or hard to find. You just found one.
Someone may have an oil filled to sell you cheaper.
73 Dan Magro, RADIODAN W7RF, (member SCDXC)
Henry HF Amps are "Instant on" for RF Power now!
Rugged, Reliable HENRY RF Power Amplifiers for LESS!
Trust one of your own, a DXer & Contester.
http://www.radiodan.com??? RFpower@radiodan.com
<mailto:RFpower@radiodan.com> A trip to our web site is worth the click!
> -----Original Message-----
> From: owner-amps@contesting.com [mailto:owner-amps@contesting.com]On
> Behalf Of km1h@juno.com
> Sent: Monday, September 28, 1998 7:24 AM
> To: amps@contesting.com
> Subject: Re: [AMPS] Series Parallel Electrolytics & Current
>
>
>
>
> On Sun, 27 Sep 98 18:36:26 -0800 Rich Measures <measures@vc.net> writes:
> >
> >>Hi Rich
> >>
> >>I am sure I am just missing something but what are the DIGI-KEY part
> ># for
> >>the 105 degree 470uF Caps. ......
> >
> >P10170-ND. Thanks for the heads up, Paul. I intended to put this
> >in the article.
> >>
> >>> 105º deg C rated electrolytic capacitors last much longer than 85º
> >C
> >>rated electrolytics. - - I would use 2x 24 Panasonic [Matsushita]
> >>470uF, 450v, 105º C rated units in series parallel. This would
> >deliver
> >>about 40uF @10.8kWV. I would use one 100k ohm, 3w equalizer resistor
> >>across each pair of paralleled 470uF units. It is my opinion that
> >for SSB
> >>operation, less C would work ok. Also, I would mount the individual
> >>electrolytics on a 7mm or more-thick acrylic sheet with silicone
> >rubber adhesive to reduce
> >>case stress. (Digikey currently sells these caps. at c. $12.20 each
> >in
> >>10 unit quantities.)
> >>>
> >rong. Current pricing is $13.85 ea. for 10 - 99 units.
>
>
> Identical rated caps made in the USA by CDE are available from Mouser.
> Part # 381LX471M450A052 ( Mouser # 5985-450V470) are $11.29 ea Qty
> 10-99.
>
> These and the Panasonic are good caps but be careful of the ESR and
> ripple current ratings which are signifigantly worse than computer grade
> caps.
> Mouser carries the Mallory line of CGS and prices are just a little bit
> more than the smaller caps.
> If you design for less C as Rich suggested you can save quite a bit of
> money.
> Mouser also carries 3 and 5W MOX resistors.
>
> BTW, I find that Mouser almost always has better prices than Digi-Key.
>
> 73 Carl KM1H
>
>
>
>
>
> >>>> Oil capacitors are
> >>>>hard or too expensive to find. The Current rating of most
> >>>>electrolytics are around 1 amp, how would they operate at this
> >current?
> >>>
> >>> At 3A on RTTY, Hot. The solution is to use paralleled units to
> >divide
> >>the ripple current burden. It's not a bad idea for electrolytics to
> >be
> >>mounted with air gaps and to use a bit of forced air cooling.
> >>>>
> >>>>
> >>>- later, Igor
> >>>
> >>>
> >>>Rich. Measures. Web site: www.vcnet.com/measures
> >>>
> >>>
> >>>--
> >>>FAQ on WWW: http://www.contesting.com/ampfaq.html
> >>>Submissions: amps@contesting.com
> >>>Administrative requests: amps-REQUEST@contesting.com
> >>>Problems: owner-amps@contesting.com
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> >>>
> >>Paul J Hellenberg W9JA ex KS9K Tru Line Lithographing Inc.
> >>PO BOX 565 7900 Durand Av., Sturtevant WI 53177-0565
> >>414 554 7300 -125 Fax 414 554 8217 Home 414 554 9170
> >>http://www.contesting.com/Tours/W9JA/w9jahome.htm
> >
> >
> >
> >Rich...
> >
> >R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures
> >
> >
> >--
> >FAQ on WWW: http://www.contesting.com/ampfaq.html
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> >
> >
>
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