Hi, The LPRO is shown to run down to 18 volt supply which reduces the power dissipation, see the graph in the manual. Like Mike I put one on to a heatsink and used a tiny under-run 12V fan to cool it. I placed a thermistor on the heat sink and controlled the fan to keep the heat sink to about 37C. I insulated the assembly so it can handle low temperatures. It hold this within +or- 0.05 degree, which is a tremendous assist to the non-ovened XO. It also reduces the power demand to about 7 or 8 watts. There is a small burden on the MTBF specs, but in my book quite acceptable. When I finish building some more gear I will get the improved performance data, cheers, Neville Michie
On 12/01/2009, at 6:07 PM, Michael Baker wrote: > Hello, Timenutters-- > > I only have experience with four different LPRO-101 > units, but with respect to heatsinking, all 4 behaved > identically during my testing of them. > > It appears that the LPRO-101 units do not require > much heatsinking. I experimented with a variety > of heatsinks and discovered that just bolting them > down to a 1/8" thick flat sheet of aluminum roughly > 8" x 10" (no fins, just a flat sheet) kept the > case of the unit and the aluminum sheet below > 105 deg F. That is relatively quite cool as far > as electronic circuitry is concerned-- only > slightly warm to the touch. > > The 4 units I tested were powered by a regulated > 24VDC supply and the aluminum sheet was kept vertical > and had good air flow around it. > > I also experimented with a heat sink that is very > nearly the same size as the base plate of the LPRO > units but only has ten 1/2" tall fins that are > quite wide spaced on it. With that particular > very minimal heatsink the highest temp reached after > 4 hours was only 97 deg F. > > I put a teeny 12 volt CPU fan about 2" from the fins and > ran it on 6 volts DC to keep the blade speed waaaaaaay > down (and essentially silent). After two hours had > elapsed, the heat sink and case were still only > ever so slightly above room temperature. > > Bottom line seems to be that the LPRO units must have > at least some minimal heatsinking but they do not > require much. The four units I tested came to me > with their base plates covered with a very thin layer > of some sort of a pale green heat transfer material > so I did not need to apply any of the typical > messy white "moose-poop" zinc-oxide and silicone grease > heat transfer paste. > > Mike Baker > WA4HFR > Gainesville (Micanopy) Florida > --------------------------------------- > > > > > > > _______________________________________________ > time-nuts mailing list -- [email protected] > To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/ > time-nuts > and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
