Hi Yes, I have seen several Rb's die from what I believe were temperature related causes. Since it's an accelerated MTBF sort of thing, *proving* they were temperature related is difficult. Put another way - I believe the manufacturer's data on MTBF vs temperature is fairly accurate. At elevated temperatures, the life of the device is in the "few years" (2 to 4) range.
Bob -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Chuck Harris Sent: Monday, July 18, 2011 12:00 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Rb cooling For all of this attention to cooling the oven on the Rb standards, has anyone seen any failures that are attributable to heat? I sort of doubt it. -Chuck Harris [email protected] wrote: > I monitor and fan cool the base plate, stays nice and constant at 45 C > which I can not say with heat sink only. I am considering lowering the base > plate to 40 C. I have a heat sink on the base plate with the fan blowing over > it. Makes good heat exchanger. I have experimented with heat pipes from Lap > Tops but never fit for mechanical reasons. May work with a LPRO's. Al my > Rb's are Efratom. > A variable speed fan will reduce any ambient temperature influence. That is > why I chose to use a fan. > Use a dual Op Amp for temp. control. Nothing special. Fans are $ 3.00 I > have monitored points inside the Rb's and they are within 1 C over time. > Bert Kehren _______________________________________________ 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.
