Fan connectors, motherboards, and power supplies

Discussion in 'Asus' started by electric sheep, Sep 11, 2003.

  1. Hi,
    I have an antec fan I got from somewhere.
    It has a 3 prong connector, and a traditional 4 socket connector (like what
    connects to hard drives).
    It works with the 4-socket, but not when the 3-prong is plugged into the
    mobo's "power fan" connector.

    However, I noticed when both are plugged in the BIOS can detect the RPM's on
    the fan.
    So my question is, is that 3-prong connector just for relaying "information"
    to the mobo basically ?
    And not for actually supplying power ?
    I know I've seen a 3-prong to 4-socket adapter before, so I'm assuming that
    it should be able to supply power.

    I would think either the mobo or the fac were busted, but then how could the
    mobo know it was there and what the RPM's are ?
    I couldnt find anything in the BIOS to "enable the fan".

    Also, my antec power supply has an identical 3-prong deal.
    Is this for relaying info on the state of the power supply fan ?
    Maybe some 3-prongs are set up to accept power and others are set up for
    "informational" purposes ?
    electric sheep, Sep 11, 2003
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  2. Not sure i understand this have two connectors on this fan?...or
    does the fan have a 3 pin connector with red, black, yellow wires?

    The yellow wire is for fan RPM detection in BIOS, the other two wires supply

    If it does have two connectors then just plug one into your mobo for fan RPM
    detection and the other 4 pin to your power supply.

    Yes...if that connector only has one wire, if it's just a yellow wire then
    this connector is just designed to be used for fan RPM detection's
    not to supply power to the fan or using the mobo to power the fan.

    It can and it does, that fan might have a high power usage, maybe a high RPM
    fan that eats alot of juice...thus powering it from the mobo might damage
    the mobo and the fan.

    So you have a 4 pin connector for connecting direct to your power supply,
    and i am betting this 4 pin only has two wires connected to it, red and

    Then a separte connector that's a smaller 3 pin with just one wire,
    yellow...thus you're getting the best of both worlds.
    You don't enable anything, all you do is enable the mobo to detect fan RPM.

    Good god man, RTFM!!!! connect that 3 pin Antec connector to your's just for fan RPM detection in BIOS.

    YES...look at the wires, if it's only got one wire attached, a yellow one,
    it's only intended for fan RPM detection.
    Richard Dower, Sep 11, 2003
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  3. yeah, it has a 3-pin connector, but i think it only has 2 wires ... both the
    same color.
    maybe it is missing the power wires is the deal.
    the other connector is just like a hard drives.

    maybe for some reason they prefer you to get juice from the power supply,
    but give you the other connector so the mobo can monitor it ?
    that's probably all it is.

    How about the power supply 3-pin connector ?
    Is that so you can monitor the power supplies fan I guess ?
    electric sheep, Sep 11, 2003
  4. What colors?...if it's red and black then this is for power only, not fan

    It could be faulty or damaged, what not simply buy some nice new fans from

    They do...if the fan is high RPM and eats alot of juice you must connect it
    directly to the power supply.

    They then have a separte 3 pin connector with just a yellow wire that allows
    you to monitor fan RPM.

    Yes...this is mine:

    I connect the 3 pin direct to the mobo for fan RPM detection in BIOS.
    Richard Dower, Sep 11, 2003
  5. electric sheep

    Dan Spears Guest

    The new vantec 80 mm fans have a three pin connect to connect to the
    motherboard that reads the RPM's only. No power on the three pin connector.
    The four pin connect is where the fan gets it's power. You can still buy the
    vantec three pin only connector but they are very rare since they have been
    Dan Spears, Sep 11, 2003
  6. I have them, i have seven 80mm Vantec Stealth fans with the 3 pin connector,
    they are all hooked to the Digital Doc 5 for fan RPM monitoring and power.
    It keeps everything nice and tidy.
    Richard Dower, Sep 11, 2003
  7. electric sheep

    R_Supp Guest

    Your fan is rated at 12.5 watt and your mobo fan headers are rated at just a
    tad over 8 watt so if you could connect the fan to the mobo you would fry
    the header. Connecting the fan to the PSU and the tacho wire to the header
    is the correct way to use this fan.
    Always check fan specs before blindly connecting them to the mobo.
    R_Supp, Sep 12, 2003
  8. High-speed or high-airflow fans typically draw a lot of power, more in some
    cases than the motherboard fan connectors can supply without burning the
    traces on the board. In this case, they use a power supply connector for the
    power, and the 3-pin connector is for RPM monitoring only.
    Robert Hancock, Sep 12, 2003
  9. Remains to be said that if you're using one or even more fans drawing
    12.5 watts in an ordinary home PC you're most likely doing something
    wrong in terms of ventilation, not to mention deafness before and/or or
    after using those. ;) Two 26 cfm / 45m^3/h 80x80 fans (<2 watts and ~20
    dB(A) each) at the back of the case shouldn't have much trouble even
    with the heat generated by a P4 3.2 GHz and a Radeon 9800 Pro. Just
    looking at the specs for the Vantec Tornado that indeed draws 12.5 watts
    - a 92x92x38 fan rotating at 4800 rpm with an airflow of 119 cfm (!!!)
    and a noise level of 56.4 dB(A) (ouch!!!1). Might make a nice motor for
    a model jet or something, but apart from that it's not something you'd
    want to have near you when powered on, let alone in a PC!

    Stephan Grossklass, Sep 12, 2003
  10. I've got 14 fans in my case, yes it's like being at an airport, with most of
    the noise generated by the Volcano 7+....but i'm used to the noise now.
    Richard Dower, Sep 12, 2003
  11. electric sheep

    r Guest


    r, Sep 17, 2003
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