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/
