Also, don't forget simply using a controller that directly supports fans: <http://www.ah6le.net/arcom/index.html> . Simple doesn't necessarily mean cheap. To some people, plug-n-play is the most simple form. Not that these controllers are plug-n-play, but a relay circuit is easy enough for most people. The timing is in the controller.
Joe M. Mike Morris WA6ILQ wrote: > > At 05:04 AM 12/25/03 +0000, you wrote: > > >I need a simple circuit for a repeater PA fan controller with delay > >time out. > > See below > > > I did a search, but found nothing. > > That's funny. I put the three words > "repeater" "fan" "control" into Google > and got over 16,000 hits. The first 30 or > so were interesting. > > > Thanks de David > > The simplest way involves no delay. > Just run the fans continuous until you build a fan control > board. > > I took advantage of the fact that at the surplus electronics > stores the 220v muffin fans are priced way cheaper than the > identical 120v ones. The 220v ones run just fine at 120v just > a lot quieter and a lot slower (which means they last longer). > Even at half voltage they blow enough air on a heat sink to > keep it cool. The ones with brass sleeve bearings will last a > couple of years continuous, the ones with ball or roller bearings > will last 5 years or so. > > If all you can find is 120v ones just put two of them in series. > > I bought six of the 220v ones (at $2 each) and have one on each > Mitrek link radio heat sink, two on the Micor repeater > heat sink and two spares. > > I have a Klixon thermal switch on each heat sink wired > to turn on a extra fan and to provide an alert of the > overheating condition. See the last schematic on the > web page at <http://www.repeater-builder.com/mitrek/mitrek-interfacing.html> > > There was also a fan control project in the July 2003 QST > by N8AKS. If you aren't a subscriber then somebody in > your ham club probably is. Borrow the issue and xerox the > article. > > Another controller is at > http://www.seits.org/repeater/rptfan.htm > The link to the schematic is broken in the article, use > this one: http://www.seits.org/repeater/rptfan.gif > > Another article is at > http://sound.westhost.com/project42.htm > > Now that I've done the homework for you I'd like you to > let us know what you decide. > > Or write an article on fan control for www.repeater-builder.com > > Mike WA6ILQ > > > > Yahoo! Groups Links > > To visit your group on the web, go to: > http://groups.yahoo.com/group/Repeater-Builder/ > > To unsubscribe from this group, send an email to: > [EMAIL PROTECTED] > > Your use of Yahoo! Groups is subject to: > http://docs.yahoo.com/info/terms/ Yahoo! Groups Links To visit your group on the web, go to: http://groups.yahoo.com/group/Repeater-Builder/ To unsubscribe from this group, send an email to: [EMAIL PROTECTED] Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/
