Note: Topic on fan wiring

Discussion in 'Incubating & Hatching Eggs' started by keaton85, Sep 19, 2010.

  1. keaton85

    keaton85 Out Of The Brooder

    Sep 8, 2010
    This is pretty basic but I have not seen people talk about voltage and amps for these fans to work.

    1: Most all computer fans are brushless ball bearing type running off of 12V DC (you want brushless!!!!)
    2: They can only be hooked up one way (likely diode controlled)
    3: Amperage of the wall plug in (transformer) does play a roll.
    4: Voltage does not have to be spot on!

    Taking those things into consideration, your likely looking for a 12V 500mA (1/2 amp) transformer. Most fans will state the proper operating voltage and amperage. You should be ok going above this a little. So if your fan is 12V .30amps then you are looking for a 12V 300mA transformer to meet the exact specs. In reality you can go with a 7V, 10V or even 15V BUT you have to gauge how fast the fan is going. Running off of a 7V or 10V transformer will likely slow the fan to much, depending on the side of the incubator. OR in turn a 15V might be to fast for the incubator.

    Anyway, what I'm trying to say is you have some wiggle room here, don't be freaked out if you can't find a transformer that hits spot on. Ive hooked up a 30V transformer to a 12V fan and it work's, although a little fast for what I need.

    The best I can really think of is a 120MM fan, which in my opinion pushes a good amount of air around while keeping the noise down...

    If you have any questions on this feel free to ask as I know some of you might not understand exactly what to do with your dump find computer fan!
    Last edited: Sep 19, 2010
  2. muddstopper

    muddstopper Chillin' With My Peeps

    Aug 23, 2008
    Murphy NC
    With your mention of computer fans and dc voltage, I am assuming you are referring to fans for small homemade incubators or the small Styrofoam LG’s and such, I agree that voltage isn’t critical to operate these type of fans, but more critical is the amount of air these fans will move. Usually rated in cubic feet per minute or CFM’s. Using to high of dc voltage will speed up those small fans and increase air speed and low voltage will slow down the fan and decrease air speed. With recycled computer fans, you really don’t know how much air (CFM) the fan is rated to move, nor do you know how much altering the recommended voltage will affect the rated air flow (CFM).

    Too much air speed will cause excessive evaporation from inside the egg, even though you might be maintaining proper humidity levels. As the air moves across the eggs, it will pull moisture from inside the porous egg and circulate that moisture inside the incubator. The net result is a false humidity reading and not a true reading of what is going on inside the eggshell. Your humidity could be perfect, yet you could still end-up with shrink-wrapped chicks because of to much wind speed.

    What I have found that seems to work best with my cabinet incubators is to try to circulate the air inside the incubator no more than 6 or 7 times per minute. To do this I compute the cubic area inside my incubators and buy a fan that is 6 or 7 times larger than that. If my incubator has a cubic area of 10cubic ft, I would look for a fan that blows about 60 or 70 CFM’s Being on the low side of 6-7 times recirculation of air is better than being on the high side of recirculation. What I am looking for is a constant air movement, without a breeze blowing across my eggs. To experiment, I have taken thin strips of paper and suspended them inside the incubator egg tray areas. With the fans running I want to just barely see the paper strips move around. If the paper strips are flapping, I know I have too much wind speed and will downsize the fan.

    Of course, you could purchase one of those hand held wind speed meters and put inside the incubator if you want to accurately measure wind speed, but the suspended strips of paper works for me.

    I found this site,
    be a pretty good source of 110v fans at a reasonable price. Plenty of sizes to choose from. And here, for small dc fans of varying sizes and dc voltages.

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