[Amps] Q: Chimneys for 3-500/4-400??

Steve Katz stevek@jmr.com
Wed, 4 Dec 2002 07:46:13 -0800


Hi Ian,

Yes, it would be imprudent to operate the amplifier without its cover
installed, just as it would be to operate a pressurized chassis (blower, air
system socket, chimneys) without its bottom cover installed!

WB2WIK/6

"If everything seems under control, you're just not going fast enough." -
Mario Andretti

> -----Original Message-----
> From:	Ian White, G3SEK [SMTP:G3SEK@ifwtech.co.uk]
> Sent:	Tuesday, December 03, 2002 4:04 PM
> To:	amps@contesting.com
> Subject:	Re: [Amps] Q: Chimneys for 3-500/4-400??
> 
> Steve Katz wrote:
> 
> >I'm guessing:
> [...]
> >
> >-The critical and well-selected spacing of the axial fan to the tube 
> >envelopes results in about equal cooling of the entire envelopes, 
> >including the surface opposite the side with the air applied -- kind of 
> >clever.
> >
> 
> A while ago, I made some rough measurements on the 3-500Z in an SB-1000, 
> using thermal-sensitive labels on the glass. That amp has a 6in 
> Muffin-type fan blowing across the tube, with the air outlet for the 
> whole cabinet on the opposite side of the tube.
> 
> In normal operation the temperature on the downstream side of the tube 
> was a little higher than the upstream side... maybe 50C, not enough to 
> be a problem.
> 
> The real problem came when the top cover was removed. When there was no 
> outlet hole to guide the air around the tube, the downstream side became 
> a stagnant air pocket and the temperature shot off-scale.
> 
> 
> -- 
> 73 from Ian G3SEK         'In Practice' columnist for RadCom (RSGB)
>                             Editor, 'The VHF/UHF DX Book'
> http://www.ifwtech.co.uk/g3sek
> _______________________________________________
> Amps mailing list
> Amps@contesting.com
> http://lists.contesting.com/mailman/listinfo/amps