Hi I may be looking in the wrong places for my parts. The ones I have seen appear to use about a watt to pump a watt at zero delta T. That still means putting a lot of DC current into the system.
I'm thinking that a recirculating water loop with a radiator (or TE cooler) remote from the rubidium may be a reasonable way to go. I still need to do some homework on cost. Bob On Dec 24, 2009, at 11:54 AM, J. Forster wrote: > The trick is you use the TE devices at near zero delta-T. They will pump > much more heat and dissipate little power. > > -John > > =============== > > >> Hi >> >> THe problem with cooler chips is that the heat still has to go somewhere. >> On the "other side" of the device you need to deal with both the original >> 10 or 20 watts plus the heat from the cooler. To move 10 or 20 watts and >> get a significant delta T you need a pretty big cooler chip. Since they >> are low voltage, that gets you right back to lots of current and thus >> magnetic fields. >> >> The idea of putting the cooler a distance from the cell and coupling with >> moving air is still an option though. >> >> Bob >> >> >> On Dec 24, 2009, at 9:28 AM, Steve Rooke wrote: >> >>> I wonder how peltier devices would work for this application. Coupled >>> with a temperature feedback servo they could be used to heat/cool the >>> rubidium. Does anyone know if they have any electromagnetic field >>> issues with them, the ones I have seen seem to be completely enclosed >>> in aluminium which should act as a Faraday cage. They have the >>> potential of providing a large thermal transfer capability compared >>> with passive devices. >>> >>> 73, >>> Steve >>> >>> 2009/12/25 Joe Gwinn <[email protected]>: >>>> At 10:06 PM +0000 12/23/09, [email protected] wrote: >>>>> >>>>> Date: Thu, 24 Dec 2009 09:46:13 +1300 >>>>> From: Bruce Griffiths <[email protected]> >>>>> Subject: Re: [time-nuts] Cheap Rubidium >>>>> To: Discussion of precise time and frequency measurement >>>>> <[email protected]> >>>>> >>>>> Joe Gwinn wrote: >>>>>>> >>>>>>> Date: Thu, 24 Dec 2009 08:57:42 +1300 >>>>>>> From: Bruce Griffiths <[email protected]> >>>>>>> Subject: Re: [time-nuts] Cheap Rubidium >>>>>>> To: Discussion of precise time and frequency measurement >>>>> >>>>>>> <[email protected]> >>>>>>> >>>> >>>> [snip] >>>> >>>>>>>> Distributed heating using wire wound or printed heaters perhaps, >>>>>> but >>>>>> to >>>>>>>> >>>>>>>> reduce the associated magnetic field bifilar winding should be >>>>>>>> considered. >>>>>>> >>>>>>> Non-inductive power resistors, which are commercially available, >>>>>>> have >>>>>>> very low magnetic fields. >>>>>>> >>>>>>> The low-inductance resistors have Ayrton-Perry windings, which are >>>>>>> bifilar. >>>>> >>>>> No, Ayrton-Perry windings arent bifilar. >>>>> >>>>> Classically a flattened helical winding was made on a insulating card. >>>>> An identical winding was then wound in the opposite direction on top >>>>> of >>>>> the first winding and the 2 were connected in parallel. >>>>> The idea being that the small magnetic field produced by one flattened >>>>> helix is cancelled by that of the other flattened helix. >>>> >>>> True enough - while there are two conductors, they are not close and >>>> parallel. >>>> >>>> Anyway, the point is that non-inductive components by definition have >>>> low >>>> magnetic fields, and that non-inductive power resistors are common. >>>> >>>> To eliminate the field from the loop of resistors, one can have a >>>> linear >>>> string of A-P resistors in series, with a pair of return wires in >>>> parallel, >>>> with the return wires on either side of the resistor string, thus >>>> reducing >>>> the effective loop area. >>>> >>>> Joe >>>> >>>> >>>> _______________________________________________ >>>> 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. >>>> >>> >>> >>> >>> -- >>> Steve Rooke - ZL3TUV & G8KVD >>> A man with one clock knows what time it is; >>> A man with two clocks is never quite sure. >>> >>> _______________________________________________ >>> 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. >> >> > > > > _______________________________________________ > 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.
