User Tag List

Informational! Informational!:  0
Likes Likes:  0
Page 2 of 3 FirstFirst 123 LastLast
Results 9 to 16 of 21

Thread: Computer Fans

  1. #9
    Zero's Avatar
    Join Date
    Aug 2005
    Location
    Dark side of the Moon
    Posts
    1,299
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Good write up mrflytrap.
    I use extra computer fans and old cell phone chargers. I just wired them together and they have worked great for 3 years. Didn't cost me anything
    SK-8 OR DIE

    growlist

  2. #10
    Let's positive thinking! seedjar's Avatar
    Join Date
    Dec 2004
    Location
    Olympia, Washington
    Posts
    4,064
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    One question, although I think the answer can be inferred from your post; when matching voltage and amperage, which needs to go over and which under? I think it's that the amperage of the transformer should be under the amperage for the fan, and the voltage is the opposite (transformer must be equal to or greater than the rating on the fan.) Correct?
    ~Joe
    o//~ Livin' like a bug ain't easy / My old clothes don't seem to fit me /
    I got little tiny bug feet / I don't really know what bugs eat /
    Don't want no one steppin' on me / Now I'm sympathizin' with fleas /
    Livin' like a bug ain't easy / Livin' like a bug ain't easy... o//~

  3. #11
    Av8tor1's Avatar
    Join Date
    Jan 2007
    Posts
    4,811
    Mentioned
    6 Post(s)
    Tagged
    0 Thread(s)
    excuse me for jumping in but to understand amps and voltage it may be easier to think of a water pump. Voltage in electricity can be thought of as basically a measurement of pressure differential and amperage as a measurement of flow rate.

    In an electrical power supply the amperage rating it has is the amount of "flow" it can maintain before it begins to lose voltage (or overheats depending on design)

    So if a power supply is rated at 1amp at 12vdc it can supply that much flow if required without a drop in pressure (voltage) or excessive heat.

    If you exceed the amperage rating then the powersupply's voltage will start to drop and/or excessive heat will start to build up.

    Of course there is usually a decent "safety factor" built into these units.

    If you have a 1amp powersupply but the "load" only uses 0.25a then that is all that will flow, the 1amp rating is a max rating.

    personally I would recommend to use a power supply with the correct voltage and at least the amperage that the fan/s are rated, 10% over is always a nice buffer for the unexpected.

    Interestingly enough, these fans are axial flow dynamic air pumps and their amperage rating is directly proportional to air flow, so if air flow is restricted their draw actually goes down... I know, counterintuitive but true

    so to make a long story short, yes there is room to play... to a degree, but its best if the voltage is spot on and the power supply's amperage rating exceeds the load rating.

    HTH's
    Av

  4. #12
    Let's positive thinking! seedjar's Avatar
    Join Date
    Dec 2004
    Location
    Olympia, Washington
    Posts
    4,064
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    So... I got it backwards, then? I fail at electrical engineering.
    ~Joe
    o//~ Livin' like a bug ain't easy / My old clothes don't seem to fit me /
    I got little tiny bug feet / I don't really know what bugs eat /
    Don't want no one steppin' on me / Now I'm sympathizin' with fleas /
    Livin' like a bug ain't easy / Livin' like a bug ain't easy... o//~

  5. #13
    OMG h8 pings MrFlyTrap2's Avatar
    Join Date
    Jan 2007
    Location
    DeKalb, IL
    Posts
    682
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    To make matters even more gray the safety factor designed in is also a -+ for bad manufacturing of the supply accuracy. I've seen many 5V supplies run 8v - 12v as well.

    If you cut the amperage too low the fan will probably still spin but not at it's true strength (not putting out enough air current). I just warn to stay away from supplies that are willing to give you high amps say 2 as it may start to melt or catch on smoke if you short the wires incorrectly.

    Basically if you hook it up, and the fan spins for longer than 10 seconds without smelling like it's burning you did it right!

    Nate
    My Grow List

    "It is only by studying nature that can we ever hope to defeat it."

  6. #14
    D_muscipula's Avatar
    Join Date
    Aug 2007
    Location
    Oregon
    Posts
    1,500
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    view my growlist
    http://grwlist.notlong.com

  7. #15
    Hello, I must be going... Not a Number's Avatar
    Join Date
    Nov 2006
    Location
    Los Angeles, CA
    Posts
    7,506
    Mentioned
    5 Post(s)
    Tagged
    0 Thread(s)
    An AC to DC power supply/converter should have a rectifier built-in. That's how the AC is normally converted to DC.

    If you are hooking up more than one fan they should be wired in parallel, not series.

    Note: Some fans can have 3 or more wires. Normally the third wire is used to measure the RPMs of the fan but can also be used for multiple speed control. Hooking up power incorrectly to the tachometer wire can burn out the fan. Unless the fan comes with a wiring diagram, avoid fans with more than two wires.
    Grand Hotel... always the same. People come, people go. Nothing ever happens.

  8. #16
    OMG h8 pings MrFlyTrap2's Avatar
    Join Date
    Jan 2007
    Location
    DeKalb, IL
    Posts
    682
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    As not a number stated, there's no need to worry about a rectifier. Pay attention to what I said about looking for a transformer that already outputs DC.

    Plus DM, just popping a diagram like that isn't really helpful without any explanation. Also you seem to be mixing diagram conventions, using something not very standard, or just incorrect. It appears you're showing the source power as connected to both grounds. This is the standard labeling of a rectifier. http://www.electronics2000.co.uk/images/data/bridge.gif
    My Grow List

    "It is only by studying nature that can we ever hope to defeat it."

Page 2 of 3 FirstFirst 123 LastLast

Similar Threads

  1. 2 fans or 1?
    By ilbasso in forum Greenhouses, Terrariums and Bog Gardens
    Replies: 1
    Last Post: 09-13-2007, 10:18 AM
  2. Replies: 12
    Last Post: 03-16-2007, 07:53 AM
  3. Any other fans of
    By Nflytrap in forum General Discussions
    Replies: 3
    Last Post: 10-01-2005, 08:50 PM
  4. Ddr fans?
    By HellzDungeon in forum General Discussions
    Replies: 8
    Last Post: 01-30-2005, 11:57 PM
  5. Cpu/computer cooling fans
    By nahasapeemapetilon in forum General Discussions
    Replies: 1
    Last Post: 11-10-2002, 06:13 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •