12V trimmer

Discussion in 'NZ Computing' started by Peter Huebner, Aug 22, 2007.

  1. I want to try and slow down the pump on my watercooling setup (seems the
    pressure is possibly too high and I am getting cavitation with the resulting
    noise).

    Any suggestions what might be a good value for a trimmer pot to get the 12V
    down to between 10 and 7 and keep up a good working current for the pump? I
    haven't done this sort of thing for a couple of decades ...

    -P.

    --
    =========================================
    firstname dot lastname at gmail fullstop com
    Peter Huebner, Aug 22, 2007
    #1
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  2. Peter Huebner

    Malcolm Guest

    On Thu, 23 Aug 2007 03:15:21 +1200
    Peter Huebner <> wrote:

    >
    > I want to try and slow down the pump on my watercooling setup (seems
    > the pressure is possibly too high and I am getting cavitation with
    > the resulting noise).
    >
    > Any suggestions what might be a good value for a trimmer pot to get
    > the 12V down to between 10 and 7 and keep up a good working current
    > for the pump? I haven't done this sort of thing for a couple of
    > decades ...
    >
    > -P.
    >

    Hi
    Would need to be a wirewound one.... What about a voltage regulator?
    You could either use a variable one LM317T or LM337T depending on
    current requirements for the pump. Then just calculate out the
    resistors (or trimpots) required in parallel/series (so you don't
    break the connection) and a 3 way switch.

    --
    Cheers Malcolm °¿° (Linux Counter #276890)
    SLED 10.0 SP1 x86_64 Kernel 2.6.16.46-0.14-smp
    up 2 days 11:30, 5 users, load average: 0.21, 0.15, 0.17
    Malcolm, Aug 22, 2007
    #2
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  3. On Thu, 23 Aug 2007 03:15:21 +1200, Peter Huebner <>
    wrote in <news:>:

    > I want to try and slow down the pump on my watercooling setup (seems the
    > pressure is possibly too high and I am getting cavitation with the resulting
    > noise).
    >
    > Any suggestions what might be a good value for a trimmer pot to get the 12V
    > down to between 10 and 7 and keep up a good working current for the pump? I
    > haven't done this sort of thing for a couple of decades ...
    >
    > -P.


    I would expect that a water pump of that nature would be ac-driven, and
    the solution may be more complicated than you anticipate. If it is
    dc-driven, it may well draw significant current which may be beyond the
    capacity of a simple carbon track series-trimpot to handle - you may have
    to consider a full-sized wire-wound pot - which may itself generate heat.

    --
    Nicolaas.


    .... There are rhythms in the world waiting for words to be written to
    them."
    Nicolaas Hawkins, Aug 22, 2007
    #3
  4. Peter Huebner

    thingy Guest

    Peter Huebner wrote:
    > I want to try and slow down the pump on my watercooling setup (seems the
    > pressure is possibly too high and I am getting cavitation with the resulting
    > noise).
    >
    > Any suggestions what might be a good value for a trimmer pot to get the 12V
    > down to between 10 and 7 and keep up a good working current for the pump? I
    > haven't done this sort of thing for a couple of decades ...
    >
    > -P.
    >


    hmm some possibilities are...

    Is it DC driven? what wattage? you can buy in-line fan controllers but
    they might not be strong enough to handle the power/amps of a pump....

    If it was me I'd look at finding the resistance through the pump, if you
    know the voltage, amps and watts you can calculate the resistance, then
    I'd go buy a suitable resistor off jaycar or DSE with the same wattage
    rating and solder it in line.......

    another alternative is try driving the pump off the 5v line...

    or building one of these....for $5,

    http://www.dse.co.nz/cgi-bin/dse.storefront/46cca180000c000e273fc0a87f330668/Product/View/K3592

    My favourite way though is buy a DSE variable voltage adaptor off DSE
    and then power it externally...

    something like this as its easily switchable,

    http://www.dse.co.nz/cgi-bin/dse.storefront/46cca180000c000e273fc0a87f330668/Product/View/M9927


    regards

    Thing
    thingy, Aug 22, 2007
    #4
  5. Peter Huebner

    thingy Guest

    Peter Huebner wrote:
    > I want to try and slow down the pump on my watercooling setup (seems the
    > pressure is possibly too high and I am getting cavitation with the resulting
    > noise).
    >
    > Any suggestions what might be a good value for a trimmer pot to get the 12V
    > down to between 10 and 7 and keep up a good working current for the pump? I
    > haven't done this sort of thing for a couple of decades ...
    >
    > -P.
    >


    This uses jumpers....

    http://www.dse.co.nz/cgi-bin/dse.storefront/46cca180000c000e273fc0a87f330668/Product/View/K3594

    regards

    Thing
    thingy, Aug 22, 2007
    #5
  6. In article <jzan4lnc6yc9$>, e says...
    > I would expect that a water pump of that nature would be ac-driven, and
    > the solution may be more complicated than you anticipate.
    >


    No, it runs off a 12V molex in the computer via a pci slot bracket.

    Dunno exactly what kind of wattage we're talking here, the fan for the radiator
    runs off the same cable, and I have two fan-speed control wires return (read
    only) for the pump and the fan. I expect maybe 8W-15W overall.

    My thought was to put a trimmer between the 12V and the ground on a molex
    splitter, then run the cooler from the wiper.

    It's one of these gadgets:
    <http://www.ascent.co.nz/productspecification.aspx?ItemID=348065>
    Cooling's remarkably good, and all the heat is taken out of the computer case,
    but it's noisy and it sounds like the pump is working way too hard against the
    flow resistance.

    Wirewound, hmmm. Must see what I have in my box of tricks. Otherwise I'll have
    to play with different inline resistors I guess.

    --
    =========================================
    firstname dot lastname at gmail fullstop com
    Peter Huebner, Aug 23, 2007
    #6
  7. In article <>, y says...
    >
    > This uses jumpers....
    >
    > http://www.dse.co.nz/cgi-bin/dse.storefront/46cca180000c000e273fc0a87f330668/Product/View/K3594
    >
    > regards
    >
    > Thing


    Nifty, thanks. I will order one of these. I prefer not to get anything
    externally powered so the cooler starts up and shuts down with the computer.

    The 1.5A may just do the trick, but it will possibly be borderline :)

    -P.

    --
    =========================================
    firstname dot lastname at gmail fullstop com
    Peter Huebner, Aug 23, 2007
    #7
  8. On Thu, 23 Aug 2007 14:59:27 +1200, Peter Huebner <>
    wrote in <news:>:

    > In article <jzan4lnc6yc9$>, e says...
    >> I would expect that a water pump of that nature would be ac-driven, and
    >> the solution may be more complicated than you anticipate.
    >>

    >
    > No, it runs off a 12V molex in the computer via a pci slot bracket.
    >
    > Dunno exactly what kind of wattage we're talking here, the fan for the radiator
    > runs off the same cable, and I have two fan-speed control wires return (read
    > only) for the pump and the fan. I expect maybe 8W-15W overall.


    I have just had a look at the manufacturer's spec sheet. It rates the
    cooling fan at 12v, 300mA (3.6w) but interestingly does not rate the pump
    motor other than to give limiting voltages (8-13.5) and throughput.
    >
    > My thought was to put a trimmer between the 12V and the ground on a molex
    > splitter, then run the cooler from the wiper.


    No. I would not do it that way. The (trim)pot would be operating as a
    voltage divider with the full 12v rail across it at all times, loading
    down the power supply needlessly and generating unwanted heat You'd
    probably let the magic smoke out.

    >
    > It's one of these gadgets:
    > <http://www.ascent.co.nz/productspecification.aspx?ItemID=348065>
    > Cooling's remarkably good, and all the heat is taken out of the computer case,
    > but it's noisy and it sounds like the pump is working way too hard against the
    > flow resistance.
    >
    > Wirewound, hmmm. Must see what I have in my box of tricks. Otherwise I'll have
    > to play with different inline resistors I guess.


    I would strongly recommend going the way of a variable, regulated supply
    fed from the 12v rail, as another correspondent suggested.

    I would NOT recommend slowing down the cooling fan - if the fliud is
    flowing more slowly it well need to carry away proportionally more heat,
    not less.



    --
    Nicolaas.


    .... A real person has two reasons for doing anything: a good reason and
    the real reason.
    Nicolaas Hawkins, Aug 23, 2007
    #8
  9. Peter Huebner

    thingy Guest

    Nicolaas Hawkins wrote:
    > On Thu, 23 Aug 2007 14:59:27 +1200, Peter Huebner <>
    > wrote in <news:>:
    >
    >> In article <jzan4lnc6yc9$>, e says...
    >>> I would expect that a water pump of that nature would be ac-driven, and
    >>> the solution may be more complicated than you anticipate.
    >>>

    >> No, it runs off a 12V molex in the computer via a pci slot bracket.
    >>
    >> Dunno exactly what kind of wattage we're talking here, the fan for the radiator
    >> runs off the same cable, and I have two fan-speed control wires return (read
    >> only) for the pump and the fan. I expect maybe 8W-15W overall.

    >
    > I have just had a look at the manufacturer's spec sheet. It rates the
    > cooling fan at 12v, 300mA (3.6w) but interestingly does not rate the pump
    > motor other than to give limiting voltages (8-13.5) and throughput.
    >> My thought was to put a trimmer between the 12V and the ground on a molex
    >> splitter, then run the cooler from the wiper.

    >
    > No. I would not do it that way. The (trim)pot would be operating as a
    > voltage divider with the full 12v rail across it at all times, loading
    > down the power supply needlessly and generating unwanted heat You'd
    > probably let the magic smoke out.
    >
    >> It's one of these gadgets:
    >> <http://www.ascent.co.nz/productspecification.aspx?ItemID=348065>
    >> Cooling's remarkably good, and all the heat is taken out of the computer case,
    >> but it's noisy and it sounds like the pump is working way too hard against the
    >> flow resistance.
    >>
    >> Wirewound, hmmm. Must see what I have in my box of tricks. Otherwise I'll have
    >> to play with different inline resistors I guess.

    >
    > I would strongly recommend going the way of a variable, regulated supply
    > fed from the 12v rail, as another correspondent suggested.
    >
    > I would NOT recommend slowing down the cooling fan - if the fliud is
    > flowing more slowly it well need to carry away proportionally more heat,
    > not less.
    >
    >
    >


    If you take out less heat then the water temp is going to rise at the
    pump suction, which could cause cavitation and more noise....slowing
    down the pump could cause the same thing.....

    From a thermal point of view the heat dissipation has gone from cpu to
    air cooled radiator to air which is pretty direct....to cpu to water to
    water to air radiator, which is a lower temp differential and a seocnd
    one....I really wonder if the water to air radiator bit is
    effective...I would have to go and work this out
    thermally/mathematically and i'd need to vendors design data to do
    so...to be sure but I'm just skeptical it achieves what it is meant to.

    regards

    Thing
    thingy, Aug 23, 2007
    #9
  10. Peter Huebner

    thingy Guest

    thingy wrote:
    > Nicolaas Hawkins wrote:
    >> On Thu, 23 Aug 2007 14:59:27 +1200, Peter Huebner <>
    >> wrote in <news:>:
    >>
    >>> In article <jzan4lnc6yc9$>, e says...
    >>>> I would expect that a water pump of that nature would be ac-driven, and
    >>>> the solution may be more complicated than you anticipate.
    >>> No, it runs off a 12V molex in the computer via a pci slot bracket.
    >>>
    >>> Dunno exactly what kind of wattage we're talking here, the fan for
    >>> the radiator runs off the same cable, and I have two fan-speed
    >>> control wires return (read only) for the pump and the fan. I expect
    >>> maybe 8W-15W overall.

    >>
    >> I have just had a look at the manufacturer's spec sheet. It rates the
    >> cooling fan at 12v, 300mA (3.6w) but interestingly does not rate the pump
    >> motor other than to give limiting voltages (8-13.5) and throughput.
    >>> My thought was to put a trimmer between the 12V and the ground on a
    >>> molex splitter, then run the cooler from the wiper.

    >>
    >> No. I would not do it that way. The (trim)pot would be operating as a
    >> voltage divider with the full 12v rail across it at all times, loading
    >> down the power supply needlessly and generating unwanted heat You'd
    >> probably let the magic smoke out.
    >>
    >>> It's one of these gadgets:
    >>> <http://www.ascent.co.nz/productspecification.aspx?ItemID=348065>
    >>> Cooling's remarkably good, and all the heat is taken out of the
    >>> computer case, but it's noisy and it sounds like the pump is working
    >>> way too hard against the flow resistance.
    >>>
    >>> Wirewound, hmmm. Must see what I have in my box of tricks. Otherwise
    >>> I'll have to play with different inline resistors I guess.

    >>
    >> I would strongly recommend going the way of a variable, regulated supply
    >> fed from the 12v rail, as another correspondent suggested.
    >>
    >> I would NOT recommend slowing down the cooling fan - if the fliud is
    >> flowing more slowly it well need to carry away proportionally more heat,
    >> not less.
    >>
    >>
    >>

    >
    > If you take out less heat then the water temp is going to rise at the
    > pump suction, which could cause cavitation and more noise....slowing
    > down the pump could cause the same thing.....
    >
    > From a thermal point of view the heat dissipation has gone from cpu to
    > air cooled radiator to air which is pretty direct....to cpu to water to
    > water to air radiator, which is a lower temp differential and a seocnd
    > one....I really wonder if the water to air radiator bit is
    > effective...I would have to go and work this out
    > thermally/mathematically and i'd need to vendors design data to do
    > so...to be sure but I'm just skeptical it achieves what it is meant to.
    >
    > regards
    >
    > Thing
    >
    >
    >


    In fact I think if you ducted the air around the cpu cooler in and out
    without mixing with the air in the rest of the case and ran a dedicated
    fan in the duct, this would be the optimum solution....

    regards

    thing
    thingy, Aug 23, 2007
    #10
  11. Peter Huebner

    Greg House Guest

    On Thu, 23 Aug 2007 15:07:38 +1200, Peter Huebner <> wrote:

    >In article <>, y says...
    >>
    >> This uses jumpers....
    >>
    >> http://www.dse.co.nz/cgi-bin/dse.storefront/46cca180000c000e273fc0a87f330668/Product/View/K3594
    >>
    >> regards
    >>
    >> Thing

    >
    >Nifty, thanks. I will order one of these. I prefer not to get anything
    >externally powered so the cooler starts up and shuts down with the computer.
    >
    >The 1.5A may just do the trick, but it will possibly be borderline :)
    >
    >-P.



    Just use one or more Diodes in series to drop the voltage, 1Amp ones might be OK if the Fan is less
    than 12W, or say 3Amp for 36W Fan..
    Greg House, Aug 23, 2007
    #11
  12. On Thu, 23 Aug 2007 16:25:32 +1200, thingy <> wrote
    in <news:>:

    > thingy wrote:
    >> Nicolaas Hawkins wrote:
    >>> On Thu, 23 Aug 2007 14:59:27 +1200, Peter Huebner <>
    >>> wrote in <news:>:
    >>>
    >>>> In article <jzan4lnc6yc9$>, e says...
    >>>>> I would expect that a water pump of that nature would be ac-driven, and
    >>>>> the solution may be more complicated than you anticipate.
    >>>> No, it runs off a 12V molex in the computer via a pci slot bracket.
    >>>>
    >>>> Dunno exactly what kind of wattage we're talking here, the fan for
    >>>> the radiator runs off the same cable, and I have two fan-speed
    >>>> control wires return (read only) for the pump and the fan. I expect
    >>>> maybe 8W-15W overall.
    >>>
    >>> I have just had a look at the manufacturer's spec sheet. It rates the
    >>> cooling fan at 12v, 300mA (3.6w) but interestingly does not rate the pump
    >>> motor other than to give limiting voltages (8-13.5) and throughput.
    >>>> My thought was to put a trimmer between the 12V and the ground on a
    >>>> molex splitter, then run the cooler from the wiper.
    >>>
    >>> No. I would not do it that way. The (trim)pot would be operating as a
    >>> voltage divider with the full 12v rail across it at all times, loading
    >>> down the power supply needlessly and generating unwanted heat You'd
    >>> probably let the magic smoke out.
    >>>
    >>>> It's one of these gadgets:
    >>>> <http://www.ascent.co.nz/productspecification.aspx?ItemID=348065>
    >>>> Cooling's remarkably good, and all the heat is taken out of the
    >>>> computer case, but it's noisy and it sounds like the pump is working
    >>>> way too hard against the flow resistance.
    >>>>
    >>>> Wirewound, hmmm. Must see what I have in my box of tricks. Otherwise
    >>>> I'll have to play with different inline resistors I guess.
    >>>
    >>> I would strongly recommend going the way of a variable, regulated supply
    >>> fed from the 12v rail, as another correspondent suggested.
    >>>
    >>> I would NOT recommend slowing down the cooling fan - if the fliud is
    >>> flowing more slowly it well need to carry away proportionally more heat,
    >>> not less.
    >>>
    >>>
    >>>

    >>
    >> If you take out less heat then the water temp is going to rise at the
    >> pump suction, which could cause cavitation and more noise....slowing
    >> down the pump could cause the same thing.....
    >>
    >> From a thermal point of view the heat dissipation has gone from cpu to
    >> air cooled radiator to air which is pretty direct....to cpu to water to
    >> water to air radiator, which is a lower temp differential and a seocnd
    >> one....I really wonder if the water to air radiator bit is
    >> effective...I would have to go and work this out
    >> thermally/mathematically and i'd need to vendors design data to do
    >> so...to be sure but I'm just skeptical it achieves what it is meant to.
    >>
    >> regards
    >>
    >> Thing
    >>

    >
    > In fact I think if you ducted the air around the cpu cooler in and out
    > without mixing with the air in the rest of the case and ran a dedicated
    > fan in the duct, this would be the optimum solution....
    >
    > regards
    >
    > thing


    You can do a lot with the proverbial basket of eggs and a big stick, eh?
    But where does one stop? How much is too much?

    If anyone REALLY wanted my advice, it would be to leave well enough alone.

    --
    Nicolaas.


    .... It is far more impressive when others discover your good qualities
    without your help.
    Nicolaas Hawkins, Aug 23, 2007
    #12
  13. In message <>, Nicolaas Hawkins wrote:

    > I would NOT recommend slowing down the cooling fan - if the fliud is
    > flowing more slowly it well need to carry away proportionally more heat,
    > not less.


    Yeah, but so what? I would expect the fluid and the entire cooling system to
    be able to cope with the full range of likely temperatures, wouldn't you?
    Lawrence D'Oliveiro, Aug 23, 2007
    #13
  14. On Thu, 23 Aug 2007 20:05:09 +1200, Lawrence D'Oliveiro
    <_zealand> wrote in
    <news:fajev2$hs7$>:

    > In message <>, Nicolaas Hawkins wrote:
    >
    >> I would NOT recommend slowing down the cooling fan - if the fliud is
    >> flowing more slowly it well need to carry away proportionally more heat,
    >> not less.

    >
    > Yeah, but so what? I would expect the fluid and the entire cooling system to
    > be able to cope with the full range of likely temperatures, wouldn't you?


    Considering the coolant will be flowing at less than its designed optimal
    speed, not necessarily.

    --
    Nicolaas.


    .... When everything's coming your way, you're in the wrong lane.
    Nicolaas Hawkins, Aug 23, 2007
    #14
  15. Peter Huebner wrote:
    > In article <>, y says...
    >> This uses jumpers....
    >>
    >> http://www.dse.co.nz/cgi-bin/dse.storefront/46cca180000c000e273fc0a87f330668/Product/View/K3594
    >>
    >> regards
    >>
    >> Thing

    >
    > Nifty, thanks. I will order one of these. I prefer not to get anything
    > externally powered so the cooler starts up and shuts down with the computer.
    >
    > The 1.5A may just do the trick, but it will possibly be borderline :)


    If you are going to use that circuit for anything approaching 1.5 Amps you will
    need to put a nice chunk of heatsink on the regulator chip. You want the
    circuit to be rated at at least twice the running current of the pump to avoid
    premature death. Many computer power supplies will die if presented by the
    short circuit of a dead 317. Some will destroy other parts of your computer as
    they go down.

    Something involving a 555 and a mosfet should do the job ...

    Roger's diode suggestion is remarkably sensible ... allow 0.65V per diode.
    Mark Robinson, Aug 23, 2007
    #15
  16. Peter Huebner

    J Brockley Guest

    "Peter Huebner" <> wrote in message
    news:...
    > In article <>, y says...
    >>
    >> This uses jumpers....
    >>
    >> http://www.dse.co.nz/cgi-bin/dse.storefront/46cca180000c000e273fc0a87f330668/Product/View/K3594
    >>
    >> regards
    >>
    >> Thing

    >
    > Nifty, thanks. I will order one of these. I prefer not to get anything
    > externally powered so the cooler starts up and shuts down with the
    > computer.
    >
    > The 1.5A may just do the trick, but it will possibly be borderline :)
    >
    > -P.


    Couple of diodes will cost next to nothing wll be easy to fit and drop the
    voltage enough to slow things down a few %.
    I use a couple on my case fans just to take the edge off the fan noise.
    J Brockley, Aug 23, 2007
    #16
  17. In message <>, Nicolaas Hawkins wrote:

    > On Thu, 23 Aug 2007 20:05:09 +1200, Lawrence D'Oliveiro
    > <_zealand> wrote in
    > <news:fajev2$hs7$>:
    >
    >> In message <>, Nicolaas Hawkins wrote:
    >>
    >>> I would NOT recommend slowing down the cooling fan - if the fliud is
    >>> flowing more slowly it well need to carry away proportionally more heat,
    >>> not less.

    >>
    >> Yeah, but so what? I would expect the fluid and the entire cooling system
    >> to be able to cope with the full range of likely temperatures, wouldn't
    >> you?

    >
    > Considering the coolant will be flowing at less than its designed optimal
    > speed, not necessarily.


    Sounds like you're thinking of a very brittle design. Something worthy of
    NASA, perhaps...
    Lawrence D'Oliveiro, Aug 23, 2007
    #17
  18. On Thu, 23 Aug 2007 23:03:52 +1200, Lawrence D'Oliveiro
    <_zealand> wrote in
    <news:fajpe5$5j0$>:

    > In message <>, Nicolaas Hawkins wrote:
    >
    >> On Thu, 23 Aug 2007 20:05:09 +1200, Lawrence D'Oliveiro
    >> <_zealand> wrote in
    >> <news:fajev2$hs7$>:
    >>
    >>> In message <>, Nicolaas Hawkins wrote:
    >>>
    >>>> I would NOT recommend slowing down the cooling fan - if the fliud is
    >>>> flowing more slowly it well need to carry away proportionally more heat,
    >>>> not less.
    >>>
    >>> Yeah, but so what? I would expect the fluid and the entire cooling system
    >>> to be able to cope with the full range of likely temperatures, wouldn't
    >>> you?

    >>
    >> Considering the coolant will be flowing at less than its designed optimal
    >> speed, not necessarily.

    >
    > Sounds like you're thinking of a very brittle design. Something worthy of
    > NASA, perhaps...


    If that is what you wish to believe, who am I to say ye 'nay!'?

    --
    Nicolaas.


    .... If you can't be kind, at least have the decency to be vague.
    Nicolaas Hawkins, Aug 23, 2007
    #18
  19. Peter Huebner

    thingy Guest

    Nicolaas Hawkins wrote:
    > On Thu, 23 Aug 2007 16:25:32 +1200, thingy <> wrote
    > in <news:>:
    >
    >> thingy wrote:
    >>> Nicolaas Hawkins wrote:
    >>>> On Thu, 23 Aug 2007 14:59:27 +1200, Peter Huebner <>
    >>>> wrote in <news:>:
    >>>>
    >>>>> In article <jzan4lnc6yc9$>, e says...
    >>>>>> I would expect that a water pump of that nature would be ac-driven, and
    >>>>>> the solution may be more complicated than you anticipate.
    >>>>> No, it runs off a 12V molex in the computer via a pci slot bracket.
    >>>>>
    >>>>> Dunno exactly what kind of wattage we're talking here, the fan for
    >>>>> the radiator runs off the same cable, and I have two fan-speed
    >>>>> control wires return (read only) for the pump and the fan. I expect
    >>>>> maybe 8W-15W overall.
    >>>> I have just had a look at the manufacturer's spec sheet. It rates the
    >>>> cooling fan at 12v, 300mA (3.6w) but interestingly does not rate the pump
    >>>> motor other than to give limiting voltages (8-13.5) and throughput.
    >>>>> My thought was to put a trimmer between the 12V and the ground on a
    >>>>> molex splitter, then run the cooler from the wiper.
    >>>> No. I would not do it that way. The (trim)pot would be operating as a
    >>>> voltage divider with the full 12v rail across it at all times, loading
    >>>> down the power supply needlessly and generating unwanted heat You'd
    >>>> probably let the magic smoke out.
    >>>>
    >>>>> It's one of these gadgets:
    >>>>> <http://www.ascent.co.nz/productspecification.aspx?ItemID=348065>
    >>>>> Cooling's remarkably good, and all the heat is taken out of the
    >>>>> computer case, but it's noisy and it sounds like the pump is working
    >>>>> way too hard against the flow resistance.
    >>>>>
    >>>>> Wirewound, hmmm. Must see what I have in my box of tricks. Otherwise
    >>>>> I'll have to play with different inline resistors I guess.
    >>>> I would strongly recommend going the way of a variable, regulated supply
    >>>> fed from the 12v rail, as another correspondent suggested.
    >>>>
    >>>> I would NOT recommend slowing down the cooling fan - if the fliud is
    >>>> flowing more slowly it well need to carry away proportionally more heat,
    >>>> not less.
    >>>>
    >>>>
    >>>>
    >>> If you take out less heat then the water temp is going to rise at the
    >>> pump suction, which could cause cavitation and more noise....slowing
    >>> down the pump could cause the same thing.....
    >>>
    >>> From a thermal point of view the heat dissipation has gone from cpu to
    >>> air cooled radiator to air which is pretty direct....to cpu to water to
    >>> water to air radiator, which is a lower temp differential and a seocnd
    >>> one....I really wonder if the water to air radiator bit is
    >>> effective...I would have to go and work this out
    >>> thermally/mathematically and i'd need to vendors design data to do
    >>> so...to be sure but I'm just skeptical it achieves what it is meant to.
    >>>
    >>> regards
    >>>
    >>> Thing
    >>>

    >> In fact I think if you ducted the air around the cpu cooler in and out
    >> without mixing with the air in the rest of the case and ran a dedicated
    >> fan in the duct, this would be the optimum solution....
    >>
    >> regards
    >>
    >> thing

    >
    > You can do a lot with the proverbial basket of eggs and a big stick, eh?
    > But where does one stop? How much is too much?
    >
    > If anyone REALLY wanted my advice, it would be to leave well enough alone.
    >


    In this instance yes....if we are only considering a point
    solution....my comments are more towards general considerations....from
    an engineering point of view water cooling the CPU on this small a unit
    is a marketing ploy and not a sound engineering one.....hence my comment
    that a ducted fan is probably the simplest and more reliable. If space
    was a huge issue and the cooler size and issue then water cooled would
    be worth it eg solving the Xbox 360's tendency to cook itself with its
    limited space....

    regards

    Thing
    thingy, Aug 23, 2007
    #19
  20. Peter Huebner

    thingy Guest

    Lawrence D'Oliveiro wrote:
    > In message <>, Nicolaas Hawkins wrote:
    >
    >> I would NOT recommend slowing down the cooling fan - if the fliud is
    >> flowing more slowly it well need to carry away proportionally more heat,
    >> not less.

    >
    > Yeah, but so what? I would expect the fluid and the entire cooling system to
    > be able to cope with the full range of likely temperatures, wouldn't you?


    no....such a design has many considerations ie you design to a cost
    and/or weight, otherwise I'd suggest a large 20 litre bucket wet dew
    point cooled solution....or even using water/gycol with a fridge plant
    run it about 4Deg C.....such units would be huge and expensive and
    massive overkill....how likely is likely....personally I consider this
    unti ie water cooling the cpu and cooling the water with a small
    radiator out the back a joke in engineering terms....

    regards

    Thing
    thingy, Aug 23, 2007
    #20
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