[Amps] SS amps watercooling

[Jim Thomson]

Date: Mon, 6 Mar 2017 14:44:51 +0000 (UTC)
From: Catherine James <catherine.james at att.net>
To: <amps at contesting.com>, Manfred Mornhinweg <manfred at ludens.cl>
Subject: Re: [Amps] SS amps watercooling

I would say the consensus is that air cooling is much simpler than liquid cooling, even if large, noisy fans are needed and the case has to be carefully designed to force flow in the right places.

It's not a coincidence that air-cool ham amplifiers are common, while liquid-cooled one are rare.

Long term, I hope we can follow Manfred's suggest to move toward Class E and other amplifier designs that are much more efficient and need less cooling.

73,
Cathy
N5WVR

##  In the UK book,  Radio Transmitters , R.F. Power Amplification,  written by VO stokes... which I posted in 3 parts on the yahoo amp group under the files section.... they cover
everything from  1kw to 500 kw.  This is all tube stuff.   Interesting to note they advise  against using water cooling, and to avoid it like the plague..... simply  cuz of the
complexity, cost, maintenance, and the pita involved.  They recommend  Air cooling, preferred, and simpler.   For broadcast use, who really cares how loud the centrifugal blowers are.   A pair of  CX-33  blowers
will easily cool a single 4CX-15000....and is a typ cooling setup for FM broadcast.   3 x CX-33 blowers will cool a single 3CX-20,000A7.   Those blowers and similar from ebm  papst 
and also  Kooltronics  will  run 24 7 365  for years on end.  Just change out the furnace  style filter.    The latest offerings from 3M  for furnace filters  are superb. Acordian shaped, for max surface area. 
They filter out dust, pollen, mites, and anything else you can think off.  A lot better made than the bottom line plane jane dust filters.  They come in all widths and lengths, typ 1 inch thick.  Then you don’t
have to be cleaning the blowers, and tube fins, etc.   Biggest air cooled tetrode in the Eimac catalog is the  4CX-35,000. 

##  I dont see any class  D, E, F, G amps that are linear....for HF  ssb use..  like the 2-30 mhz variety.   I keep looking, but dont see any....yet. 
Manfred mentioned a while back about using a conventional Pi or  PI-L  on the output of a SS amp.  I drew this out on paper, and my conclusion is, you would have to be damn careful tuning it up..and pulse tune it
with a low duty cycle.   With your  typ 50 %  eff  SS amp, mistune it, using a cxr and... kablamo.

Jim   VE7RF