----- Original Message ----- From: "mike bryce" <proso...@sssnet.com>
To: "Richard Knoppow" <1oldle...@ix.netcom.com> Cc: <captc...@flash.net>; <Drakelist@zerobeat.net> Sent: Thursday, December 16, 2010 9:32 AM Subject: Re: [Drakelist] AC4 heat Fan Summary
thought I'd toss my .02 in with a question on the tr series, a fan mounted to the rear of the pa compartment, should it blow in or suck out? since we're not trying to pressurize a compartment, there's plenty of holes in the cage and top cover, and since heat rises, it would seem to me that one would mount the fan so it would blow into and onto the final tubes To me, it seems a fan sucking air out of the pa compartment would have to compete with the natural convention of heat raising so, what's the word from the thermal gods? Mike, WB8VGE SunLight Energy Systems The Heathkit Shop http://www.theheathkitshop.com/ I noted this in my little diatribe. For the T4 the fan works best sucking the heat out from the top. Its very simple and works. Most of the heat in this TX comes from the finals and is concentrated in the final compartment. While it is in a perforated metal enclosure there is a lot of heat generated in a small area plus the addition of the external cabinet further interferes with both direct radiation of heat and convection. A small fan very significantly reduces the heat. Much of what I wrote has to do with completely enclosed spaces where the conditions are quite different from the above. Where you can control the air flow there are advantages to positive pressure but, again, one must be careful to plot out the flow of _heat_ to insure one is not getting unintended heating rather than cooling. Actually, that's the problem with using a pushing fan on something like the T4, the heat is pushed out around other components and can heat them up where the sucking fan draws cool air from around the tubes and exhausts it directly to the air. I mainly wanted to point out the differences between cooling a basically open area like the T4 final cage and a completely enclosed space like the AC-4. -- Richard Knoppow Los Angeles WB6KBL dickb...@ix.netcom.com _______________________________________________ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
