DC brushless FAN's for circuit boards

Discussion in 'General Electronics Chat' started by harrison2015, May 7, 2015.

  1. harrison2015

    Thread Starter Member

    Apr 22, 2015
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    There is different FAN's for different electronic circuit boards and power supplies. Some fans are 12 volts dc and others are 24 volts dc. The current ratings are different 0.2A , 0.13A, etc. and the wattage of the FAN. What determines the current rating of the fan? is it the type of fan motor. Does the current rating and wattage rating determine the fans RPM speed? Can I use a 24volt fan to replace a 12volt fan? the current rates and wattage rates will be different, so what will happen?
     
  2. BillB3857

    Senior Member

    Feb 28, 2009
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    Yes, some fans are 12 V and some are 24. That is the way they are made in order to operate at different voltages. Current ratings are the result of the size and voltage of the fan. The larger the fan, the more power it will take. The faster it spins, the more air it will move therefore the more power it needs. A 24 volt fan may or may not run on 12 volts. Try it and see.
    Have you thought through any of this on your own? Do your thoughts make sense? What are your thoughts?
     
  3. harrison2015

    Thread Starter Member

    Apr 22, 2015
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    I don't understand the current ratings and wattage ratings of a DC fan, is this based on the RPM's? Each fan have different current ratings and wattage ratings, so they can't be interchanged in the same circuit? or how can they be interchanged
     
  4. Sensacell

    Well-Known Member

    Jun 19, 2012
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    Fans are designed to have different performance levels, depending on what the application requires.
    System designers choose the voltage of the fan based on what voltages are available in the product.
    Interchanging fans requires matching the voltage and power requirements- along with cooling performance, mechanical size and sound levels.
     
  5. harrison2015

    Thread Starter Member

    Apr 22, 2015
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    Can the sound noise levels of the fan cause circuit board problems?
    The fan's motor has a current rating and wattage rating. But what sets the RPM's of the fan?
    Why can't I interchange a 24volt fan for a 12volt fan that have different current ratings and wattage ratings or how can I make it work?
     
  6. BillB3857

    Senior Member

    Feb 28, 2009
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    The noise level of the fan can cause problems if a microphone is mounted near it and the sound of the fan masks the sounds the microphone should be picking up. Yes, most electrical devices have current ratings and wattage ratings. Fans are no exception. The speed is determined by design based upon the amount of air that should be moved and the physical dimensions of the fan. Why can't you make an elephant fly without putting it in an airplane.
     
  7. harrison2015

    Thread Starter Member

    Apr 22, 2015
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    So the speed/RPM's of the fan have nothing to do with the current rating or wattage ratings?

    If I interchange a 24volt fan with a 12 volt fan can I just use a clamping zener diode across the fan's red and black wire without using a voltage divider?

    When powering up a fan do I need to use a current limiting resistor or I can just apply an external power supply across the fans red and black wires. I can set the power supplies current limit to 1 amp and the fan will draw whatever current it needs
     
  8. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Fans are rated at a CFM (cubic ft/min) value at the rated voltage, the higher the CFM the higher the wattage required to move the larger air mass.
    Max.
     
  9. harrison2015

    Thread Starter Member

    Apr 22, 2015
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    Does the current rating or voltage rating or wattage rating determine the RPM speed?
     
  10. MaxHeadRoom

    Expert

    Jul 18, 2013
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    The fan dia and blade design decides the CFM value at a certain RPM, the motor has to be capable, wattage wise, in order to operate at this RPM, larger muffin fans etc are generally AC 240vac/120vac powered, PC fans were brushed DC at one time, now most are BLDC.
    Max.
     
  11. harrison2015

    Thread Starter Member

    Apr 22, 2015
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    The wattage of the motor determines the RPM or the fans diameter and blades?

    The CFM value changes from plastic fans compared to cast iron or metal fans?
     
  12. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
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    Another barrage of nonsense questions.
     
    JWHassler and Reloadron like this.
  13. Sensacell

    Well-Known Member

    Jun 19, 2012
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    Explain what exactly you are trying to accomplish, then all becomes clear and easy to answer.
     
  14. blocco a spirale

    AAC Fanatic!

    Jun 18, 2008
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    He is trying to waste your time and energy.
     
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  15. djsfantasi

    AAC Fanatic!

    Apr 11, 2010
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    If it sounds like a ...
    If it feels like a ...
    If it talks like a ...
    Then it's probably a troll[​IMG]
     
  16. OBW0549

    Well-Known Member

    Mar 2, 2015
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    Not much point in replying, as the TS/OP has left the building: he, along with his three other alter-egos, apparently has been banned.
     
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