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Cooling system — Parallax Forums

Cooling system

ArchiverArchiver Posts: 46,084
edited 2004-01-10 15:11 in General Discussion
Hello everyone,

I need to add an active cooling fan to a voltage regulator and have
it switch on until the regulator is cooled down and then switch off.
I plan on doing this with a thermistor whose voltage drop is
monitored by a Stamp using A2D.

My question is how do I reliably attach the thermistor to the
regulator so that adequate heat is transferred to the thermistor. At
this point I'm thinking some kind of epoxy but wanted peoples
suggestions. Thanks in advance.

-Dave

Comments

  • ArchiverArchiver Posts: 46,084
    edited 2004-01-09 13:44
    I'd use JB weld, it's a two part epoxy that is rated for
    over 400 degrees. We use it to hold clutch plates to the
    clutch housings on model helicopters and I know of no
    instance where it has ever failed. You can get it at most
    hobby and home improvement stores.
    --
    Regards

    Dave Evartt
    American Hovercraft
  • ArchiverArchiver Posts: 46,084
    edited 2004-01-09 13:53
    You are better off if you use a thermal epoxy.
    Look at www.arcticsilver.com
  • ArchiverArchiver Posts: 46,084
    edited 2004-01-09 15:00
    Many thermistors are in a ceramic package
    (some may have paint marking, but this can be lightly sanded off on the mating
    side)

    Cyanoacrillate "a.k.a. superglue" was originally designed for medical use
    in bonding bone to ceramic and even bone to stainless steel or steel to
    ceramic.

    I personally have mounted ceramic devices to aluminum heatsinks by applying
    superglue to the metal and the pressing the ceramic to
    it.
    NOTE: Do NOT attempt to apply superglue directly to ceramic, it's bonding with
    ceramic, bone and human tissue is instantaneous, but
    when applied to metal it remains liquid till the ceramic, or your finger touches
    it, then it hardens instantaneously.

    I don't know it's thermal resistance, but I can tell you it works very well both
    in terms of holding for many years and in terms of
    heat transfer.

    KF4HAZ - Lonnie
    From: "nuclearspin2000" <nuclearspin2000@y

    > Hello everyone,
    >
    > I need to add an active cooling fan to a voltage regulator and have
    > it switch on until the regulator is cooled down and then switch off.
    > I plan on doing this with a thermistor whose voltage drop is
    > monitored by a Stamp using A2D.
    >
    > My question is how do I reliably attach the thermistor to the
    > regulator so that adequate heat is transferred to the thermistor. At
    > this point I'm thinking some kind of epoxy but wanted peoples
    > suggestions. Thanks in advance.
    >
    > -Dave
  • ArchiverArchiver Posts: 46,084
    edited 2004-01-09 20:28
    Hi Dave,

    In the "pre-Stamp" days I had a very similar application -- using a signal
    from a thermistor to activate a relay at a specific (and in this case,
    adjustable) temperature. A very inexpensive voltage comparator IC can be
    used. A few words about my application and a link to a very good intro page
    about comparators is here:

    http://www.glitchbuster.com/#LatestUpdates

    Randy
    www.glitchbuster.com


    Original Message
    From: "nuclearspin2000" <nuclearspin2000@y...>
    To: <basicstamps@yahoogroups.com>
    Sent: Thursday, January 08, 2004 9:38 PM
    Subject: [noparse][[/noparse]basicstamps] Cooling system


    > Hello everyone,
    >
    > I need to add an active cooling fan to a voltage regulator and have
    > it switch on until the regulator is cooled down and then switch off.
    > I plan on doing this with a thermistor whose voltage drop is
    > monitored by a Stamp using A2D.
    >
    > My question is how do I reliably attach the thermistor to the
    > regulator so that adequate heat is transferred to the thermistor. At
    > this point I'm thinking some kind of epoxy but wanted peoples
    > suggestions. Thanks in advance.
    >
    > -Dave
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and
    Body of the message will be ignored.
    >
    >
    > Yahoo! Groups Links
    >
    > To visit your group on the web, go to:
    > http://groups.yahoo.com/group/basicstamps/
    >
    > To unsubscribe from this group, send an email to:
    > basicstamps-unsubscribe@yahoogroups.com
    >
    > Your use of Yahoo! Groups is subject to:
    > http://docs.yahoo.com/info/terms/
    >
    >
  • ArchiverArchiver Posts: 46,084
    edited 2004-01-09 20:35
    I'd be inclinded to use one of the Dallas one wire temp
    devices and and just epoxy it to the place I wanted to
    monitor.

    my 2 cents

    ===========

    In the "pre-Stamp" days I had a very similar application --
    using a signal
    from a thermistor to activate a relay at a specific (and in
    this case,
    adjustable) temperature. A very inexpensive voltage
    comparator IC can be
    used. A few words about my application and a link to a very
    good intro page
    about comparators is here:

    http://www.glitchbuster.com/#LatestUpdates

    --
    Regards

    Dave Evartt
    American Hovercraft
  • ArchiverArchiver Posts: 46,084
    edited 2004-01-10 03:11
    Thanks for the link Randy. Lots of good stuff there.

    -Dave

    --- In basicstamps@yahoogroups.com, "Randy Jones" <randyjones@w...>
    wrote:
    > Hi Dave,
    >
    > In the "pre-Stamp" days I had a very similar application -- using a
    signal
    > from a thermistor to activate a relay at a specific (and in this
    case,
    > adjustable) temperature. A very inexpensive voltage comparator IC
    can be
    > used. A few words about my application and a link to a very good
    intro page
    > about comparators is here:
    >
    > http://www.glitchbuster.com/#LatestUpdates
    >
    > Randy
    > www.glitchbuster.com
    >
    >
    >
    Original Message
    > From: "nuclearspin2000" <nuclearspin2000@y...>
    > To: <basicstamps@yahoogroups.com>
    > Sent: Thursday, January 08, 2004 9:38 PM
    > Subject: [noparse][[/noparse]basicstamps] Cooling system
    >
    >
    > > Hello everyone,
    > >
    > > I need to add an active cooling fan to a voltage regulator and
    have
    > > it switch on until the regulator is cooled down and then switch
    off.
    > > I plan on doing this with a thermistor whose voltage drop is
    > > monitored by a Stamp using A2D.
    > >
    > > My question is how do I reliably attach the thermistor to the
    > > regulator so that adequate heat is transferred to the thermistor.
    At
    > > this point I'm thinking some kind of epoxy but wanted peoples
    > > suggestions. Thanks in advance.
    > >
    > > -Dave
    > >
    > >
    > > To UNSUBSCRIBE, just send mail to:
    > > basicstamps-unsubscribe@yahoogroups.com
    > > from the same email address that you subscribed. Text in the
    Subject and
    > Body of the message will be ignored.
    > >
    > >
    > > Yahoo! Groups Links
    > >
    > > To visit your group on the web, go to:
    > > http://groups.yahoo.com/group/basicstamps/
    > >
    > > To unsubscribe from this group, send an email to:
    > > basicstamps-unsubscribe@yahoogroups.com
    > >
    > > Your use of Yahoo! Groups is subject to:
    > > http://docs.yahoo.com/info/terms/
    > >
    > >
  • ArchiverArchiver Posts: 46,084
    edited 2004-01-10 03:13
    As usual, thanks everyone for the ideas and replies. Never a shortage
    of them around here.

    -Dave

    --- In basicstamps@yahoogroups.com, "nuclearspin2000"
    <nuclearspin2000@y...> wrote:
    > Hello everyone,
    >
    > I need to add an active cooling fan to a voltage regulator and have
    > it switch on until the regulator is cooled down and then switch
    off.
    > I plan on doing this with a thermistor whose voltage drop is
    > monitored by a Stamp using A2D.
    >
    > My question is how do I reliably attach the thermistor to the
    > regulator so that adequate heat is transferred to the thermistor.
    At
    > this point I'm thinking some kind of epoxy but wanted peoples
    > suggestions. Thanks in advance.
    >
    > -Dave
  • ArchiverArchiver Posts: 46,084
    edited 2004-01-10 04:10
    Epoxy is good but be careful. Some epoxies handle heat better than
    others. Tra-Con makes a pretty good thermally conductive/electrically
    insulative epoxy. I think Master Bond has some like that too. If you
    don't want to go to that expense and wait you might try using sodium
    silicate (waterglass). It is cheap, fire resistant and nontoxic. I have
    used it to set thermocouples onto things that get hot. Mix it with water
    to make a goo then put a little on your thermistor or thermocouple and
    let it dry over night. If you can't put it right on the component, use
    the waterglass to mount the thermistor in an uncrimped spade lug then,
    after it dries, mount the spade lug to what you want to monitor. If you
    want a quick and dirty temporary fix, try putting the thermistor in the
    spade lug and then squirting in some silicon heat sink compound. It is
    kind of messy but it works ok.

    On Fri, 09 Jan 2004 05:38:50 -0000 "nuclearspin2000"
    <nuclearspin2000@y...> writes:
    > Hello everyone,
    >
    > I need to add an active cooling fan to a voltage regulator and have
    >
    > it switch on until the regulator is cooled down and then switch off.
    >
    > I plan on doing this with a thermistor whose voltage drop is
    > monitored by a Stamp using A2D.
    >
    > My question is how do I reliably attach the thermistor to the
    > regulator so that adequate heat is transferred to the thermistor. At
    >
    > this point I'm thinking some kind of epoxy but wanted peoples
    > suggestions. Thanks in advance.
    >
    > -Dave
    >
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the
    > Subject and Body of the message will be ignored.
    >
    >
    > Yahoo! Groups Links
    >
    > To visit your group on the web, go to:
    > http://groups.yahoo.com/group/basicstamps/
    >
    > To unsubscribe from this group, send an email to:
    > basicstamps-unsubscribe@yahoogroups.com
    >
    > Your use of Yahoo! Groups is subject to:
    > http://docs.yahoo.com/info/terms/
    >
    >
    >
    >

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  • ArchiverArchiver Posts: 46,084
    edited 2004-01-10 15:11
    Hi Dave,

    I use the epoxy brand some branches of the military use to "glue"
    missile skins on (no can use rivets at multi-mach). Seems to work well
    on the back of a TO-220 heatsink that has been sanded at the interface.
    One supplier makes getting it easy.

    http://www.wassco.com/hysepkit.html

    The stuff is incredible. I've used it (along with a steel worm clamp
    reinforcing ring) to contain refrigerant in a hot condenser whose
    pressures were in the 400 to 500 pound range. That Fix Or Repair Daily
    when to the junkyard with a good refrigeration system. I've also used
    it to imbed stuffing boxes on RC boats or bond broken PC boards
    together. Handy stuff.


    To monitor component temps, I use a 10K or 50K NTC thermistor in a
    RCTIME circuit. The UNpreferred configuration with a .1 cap to ground
    eliminates most of the noisy readings (Thank you Tracy).

    When things go badly (unexpected high heat) the epoxy will discolor, but
    continue to hold where super glue will fail.





    nuclearspin2000 wrote:
    >
    > Hello everyone,
    >
    > I need to add an active cooling fan to a voltage regulator and have
    > it switch on until the regulator is cooled down and then switch off.
    > I plan on doing this with a thermistor whose voltage drop is
    > monitored by a Stamp using A2D.
    >
    > My question is how do I reliably attach the thermistor to the
    > regulator so that adequate heat is transferred to the thermistor. At
    > this point I'm thinking some kind of epoxy but wanted peoples
    > suggestions. Thanks in advance.
    >
    > -Dave
    >
    > To UNSUBSCRIBE, just send mail to:
    > basicstamps-unsubscribe@yahoogroups.com
    > from the same email address that you subscribed. Text in the Subject and Body
    of the message will be ignored.
    >
    >
    > Yahoo! Groups Links
    >
    > To visit your group on the web, go to:
    > http://groups.yahoo.com/group/basicstamps/
    >
    > To unsubscribe from this group, send an email to:
    > basicstamps-unsubscribe@yahoogroups.com
    >
    > Your use of Yahoo! Groups is subject to:
    > http://docs.yahoo.com/info/terms/
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