I agree with Eric's assessment of the NOT running fans when not needed. I do the same thing, slightly differant. I had some left over solid state Waterbed thermostats. i wired them to switch around 109 degrees (they topped out there).I wired them backwards to when the temp got to 109 they switched on a SSR. fans would only start when needed. Saves the life of the fans,filters and cuts down on the dirt inside the cabinet. I am in the process of setting up a few PURC-5000/MSF5000 on 900Mhz and 440Mhz and they all will have this type of fan controller.The PURC has a set of three fans in a rack mount.The heatsinks are MASSIVE in this beast, takes a while for it to get warm.In "Normal" operation the fans will hardly run, especially if they are in a cold mountaintop site....
Kirk On Sat, May 1, 2010 at 11:36 AM, Eric Lemmon <[email protected]> wrote: > > > Scott, > > I must agree that the CK1614 is an extremely versatile timer, with many > potential uses. However, using it for fan control is not only expensive, > but unnecessary. > > A fan blowing on a transmitter heat sink does absolutely nothing > immediately > after the transmitter is keyed, since the heat sink is likely at ambient > temperature. It takes a period of time for the heat sink to warm up, so > operating the fan prematurely is a waste of energy- which may be an issue > for a solar-powered repeater. > > IMHO, the most efficient means of fan control is also the cheapest: A > thermal switch. My first choice is a Cantherm #R2005015 normally-open > thermostat that closes at 50 degrees Celsius, about 122 degrees Fahrenheit. > When attached to a heat-sink fin, it turns the fan on when necessary, and > keeps it on until the heat sink cools below about 100 degrees F- around > body > temperature. This particular switch is available from Digi-Key for about > $9, as Catalog Number 317-1094-ND. > > 73, Eric Lemmon WB6FLY > > > > -----Original Message----- > From: [email protected]<Repeater-Builder%40yahoogroups.com> > [mailto:[email protected]<Repeater-Builder%40yahoogroups.com>] > On Behalf Of na4it > Sent: Saturday, May 01, 2010 9:38 AM > To: [email protected] <Repeater-Builder%40yahoogroups.com> > Subject: [Repeater-Builder] Neat kit for switching repeater devices > > I have started using this little kit > (http://www.electronickits.com/kit/complete/elec/ck1614.htm > <http://www.electronickits.com/kit/complete/elec/ck1614.htm> ) for fan > control on repeaters. I can also be used as a PTT and Time Out circuit, > along with a lot of other uses. > > Download the pdf on that site and check it out. > > Scott NA4IT > > >
