[R-390] R390 cooling fan

[Barry]

Of course, you could put a rat in one of those circular treadmills that is
connected to a fan blade and the amount of food and water it would get would
be proportional to the line voltage, but that'd be ridiculous, wouldn't
it...

Barry - N4BUQ

----- Original Message ----- 
From: "Barry" <n4buq at aol.com>
To: "R-390 HF Receiver List" <r-390 at mailman.qth.net>
Sent: Tuesday, July 19, 2005 1:03 PM
Subject: Re: [R-390] R390 cooling fan


> Roy,
>
> On the "new and improved" model, you should rig up a spring-loaded paddle
> that is in the direct path of the wind coming off the fan.  Affix the
paddle
> to the shaft on a variable resistor that replaces the ballast tube.  A
drop
> in line voltage will cause the fan to reduce its output thereby causing
the
> paddle to move slightly, rotating the pot, decreasing the resistance, and
> thus keeping a constant voltage to the heaters.  The opposite effect will
> occur when the line voltage increases.  Perfect!
>
> Barry "Rube Goldberg" - N4BUQ
>
> > At 11:46 AM 7/19/2005, Flowertime01 at wmconnect.com wrote:
> > >Roy,
> > >
> > >Another nice page.
> > >You sure try to help us guys along.
> >
> > Roger,
> >
> > Thanks.. glad to know that folks find it helpful.. (It's not very
fancy!)
> >
> > >From: "Dan Merz" <djmerz at 3-cities.com> ...
> > >Brad,  I used a 92 mm size fan with 35 cfm at the rated voltage.
> > >...  Mouser Orion fan because it worked for me,  ...I think Roy used
the
> > >80 mm size with flow probably around 30 cfm -
> >
> > The fan I used was a rescue item from some old computer power supply,
most
> > likely.  It is about 4 or 4-1/4 inches square.
> >
> > >  I don't know whether he
> > >ran it at less than the rated voltage.
> >
> > No, I just hooked a lamp cord to it and plugged it in. When I make
> > improvements to the system, I'll power it from the radio and most likely
> > reduce the voltage, or even use a smaller fan inside the radio mounted
on
> a
> > clamp-on bracket for a no-holes addition.
> >
> > Roy
> >
> >
> >
> >
> > - Roy Morgan, K1LKY since 1959 - Keep 'em Glowing!
> > 7130 Panorama Drive, Derwood MD 20855
> > Home: 301-330-8828 Cell 301-928-7794
> > Work: Voice: 301-975-3254,  Fax: 301-948-6213
> > roy.morgan at nist.gov --
>
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