>
>If someone wants to use 24 capacitors and all the needed resistors and labor
>and expense (24 X $10-$14 each)as a better option to an oil filled or two,
>then go for it.
>
>Just because they all CAN be strung together doesn't make it better, or
>easier, or cheaper, or smaller, or......
>
>Additional responses below.
>
>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: Rich Measures [mailto:measures@vc.net]
>> Sent: Monday, September 28, 1998 1:28 PM
>> To: Radiodan W7RF; amps@contesting.com
>> Subject: RE: [AMPS] Series Parallel Electrolytics & Current
>>
>>
>> >
>> >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
>>
>> This is not the stated rating needed.
>
>Then find a more appropriate value.
>
He said he needs 40uF @10kV. I provided a solution.
>>
>> >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.
>>
>> The 105º C electrolytics are 35mm dia. by 50mm in length, and
>> light in weight.
>
>24 of these are smaller?
>
compared to a 40uF oil filled 10kWV capacitor, less total volume and much
lighter.
>>
>> >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.
>>
>> Some have much lower ripple current ratings than high quality
>> 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.
>> >
>> I built a tetrode with handles amplifier that delivered over
>> 1150v pk into 50 ohms. The power supply delivered 9100v no
>> load. It used a compact, lightweight bank of electrolytic
>> capacitors, mounted with silicone rubber, on an acrylic sheet.
>> The measured power gain of the amplifier was x100. The power
>> supply performed with little heating and no perceptable ripple on
>> the transmitted voice signal
>
>And one can wire together 20 diodes
20 diodes per leg would be needed for an approx. 14kV supply. Whew! Now
we're talking X-rays. An 8349, Dan?
> per string in a rectifier, is that
>better than a high quality modular block?
Yes. Individual rectifiers have superior heat dissipation ability. Pot 'em
and their ability to cool themselves is reduced. A string of individual
rectifiers occupy less total space due to the fact that no heatsink is needed.
// For a 9kV no load supply, roughly (13) 1N5408s per leg would be needed.
>Maybe it's possible but not as practical.
>
Not as snazzy but it is electrically-superior since junction temperature is
reduced. // From a price standpoint, (10) 1N5408s cost approx. $2.50.
Compare that to the price of a block rect. assy. rated at 10kV @3A. -
including the price of the needed heatsink.
- later, Dan
Rich...
R. L. Measures, 805-386-3734, AG6K, www.vcnet.com/measures
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