[time-nuts] LPRO Heat Sink?

J. L. Trantham jltran at worldnet.att.net
Wed Sep 23 14:43:41 UTC 2009

The heat sink requirements are in the LPRO manual that is available on the
net.  My recollection is that the sink would require fins unless it was
monstrously thick.  The requirement is to keep the base plate less than 70
degrees C and the manual says this will require a heat sink with a thermal
resistance of less than 2 degrees C per Watt in order to achieve this in an
environment up to 50 degrees C.

You can, however, turn it on to check it for a few minutes, without a heat
sink attached.


-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of William Zimmer
Sent: Wednesday, September 23, 2009 8:41 AM
To: time-nuts at febo.com
Subject: [time-nuts] LPRO Heat Sink?

I am new to the Time-Nuts list and to the time standard area in general,
so please excuse my questions if they has been asked and answered before.

I just purchased an Efratom LPRO 101 Rubidium frequency standard.  As I
understand it, I must mount it on a heat sink.


Question 1:  The lamp and chamber operate at a temperature around 100
degrees C and we must provide sufficient power to heat the unit.  If we
are heating the unit, why do we need a heat sink?  Doesn’t the heat sink
defeat the heating process?

Question 2:  Assuming that there is a reasonable answer to question1 and
a heat sink is needed, how big a heat sink is required?  Are fins
required?  Is forced air required?  In other words, what do I have to do
to mount the LPRO 101 correctly?

Thank you in advance for your assistance.


Bill Zimmer, N3VTW
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