[time-nuts] LPRO Heat Sink?

[William Zimmer]

All, Thank you for the information. I have a much better understanding of
the heat sink requirements. I appreciate the quick response. Bill Zimmer,
N3VTW

  ----- Original Message -----
  From: "Hal Murray"
  To: "Discussion of precise time and frequency measurement"
  Subject: Re: [time-nuts] LPRO Heat Sink?
  Date: Wed, 23 Sep 2009 10:07:51 -0700



  > 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?

  The heater is for the physics package. The heat sink is for the
  electronics.


  > 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?

  It doesn't take much. What do you have handy? (Don't forget goop or
  whatever to connect the baseplate to your heatsink.)

  If you need some guesstimates to get started, try a 8 inch square of
  1/8
  aluminum. I don't think that will need a fan if you mount it
  vertically.



  > You need surface area and air flow to cool something. The air flow
  is
  > needed because there is a "film coefficient" between the HS and the
  > room air. Even minimal air flow drastically reduces the film
  > coefficient, increasing heat flow per square inch.

  Yes, but an LRRO doesn't need much. A typical noisy fan will be way
  overkill.

  Is there a rule of thumb for a flat plate mounted vertically so
  convection
  provides the air flow?


  --
  These are my opinions, not necessarily my employer's. I hate spam.




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