PWM speed control for my Fantastic Fan

Discussion in 'Heating / Cooling Systems' started by Anthony Hitchings, Nov 6, 2019.

  1. Anthony Hitchings

    Anthony Hitchings Active Member

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    as suggested elsewhere, I did this mod, I bought two PWM controllers (1 for spare). Tested controller using a light bulb for a load, then removed fan face (shroud), tested PWM directly on fan, then swapped wiring over on the face (shroud) of the fan and installed PWM to shroud body , tested, reinstalled. Note that PWM output seems to not like a common negative rail. Its a PITA working overhead. I did shorten the knob and the potentiometer shaft. For the shaft - use a small hacksaw - do not use a Dremel - a Dremel generates far too much heat. Insulated spade connectors were used between the shroud and the fan body (and supply wiring). The rheostat speed controller is totally disconnected.
     

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    Last edited: Nov 6, 2019
    PopUpSteve and 1380ken like this.
  2. bheff

    bheff Well-Known Member

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    Forgive my ignorance, but what does this do? And why is it better than just the potentiometer?
     
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  3. nineoaks2004

    nineoaks2004 Every meal is a picnic and every Day is a holiday

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    Looks good thanks for sharing
     
  4. Anthony Hitchings

    Anthony Hitchings Active Member

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    The PWM (Pulse Width Modulator) enables a speed slower than Fantastic Fan speed #1, In our Aliner even speed 1 - the slowest - is too fast most of the time. Actually, it replaces the original controller entirely. Full speed is still available. Its infinitely variable.

    Look for this on Ebay:

    6V 12V 2A 30W DC Motor Speed Controller PWM Adjustable Variable Driver Switch
     
  5. Econ

    Econ Active Member

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    Would it lower amperage useage?
     
  6. bheff

    bheff Well-Known Member

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    Neat idea. I have a fantastic fan but have never turned it on
     
  7. Anthony Hitchings

    Anthony Hitchings Active Member

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    Net energy usage will be lower using a lower speed - its that simple. Net energy usage will be less for the same speed because you have taken the (original speed control) wire coil load resistors out of the circuit.
     
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  8. matwiyj

    matwiyj Active Member

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    It would have the same result as a potentiometer, in that it can adjust the speed of the fan, but will be much more energy efficient. It basically switches the 12Vdc to the fan on and off very quickly (like, hundreds or thousands of times per second). When the fan is to be on at 10% speed, the 12V is switched to the fan for only 10% of the time. Using it would save battery power and avoid large and bulky parts like a potentiometer that can handle 2 amps.
     
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