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
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  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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  9. Econ

    Econ Active Member

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    @Anthony Hitchings
    Did your PWM bolt right up or needed modification. Mine came from Amazon and I see you are on line right now. The problem is the fan's panel is thicker than the threaded rod on the PWM.
     
  10. Econ

    Econ Active Member

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  11. Anthony Hitchings

    Anthony Hitchings Active Member

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    Using a PWM means that you will use less electricity because you fan is likely to be run at lower speeds.

    As best I can remember - I shortened the shaft on the PWM potentiometer and (maybe) also shortened the knob, so that the fan might be left with knob in place when we close the roof of the Aliner. Previously, with the as-supplied after-market Fantastic Fan - we always removed the knob before closing the roof. And also removed the vent operating handle.
     
  12. Anthony Hitchings

    Anthony Hitchings Active Member

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  13. Econ

    Econ Active Member

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    May I haved the link to the one you got?

    Thanks
     
  14. Anthony Hitchings

    Anthony Hitchings Active Member

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  15. Sjm9911

    Sjm9911 Well-Known Member

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    Nice neat instulation. Good luck with it.
     
  16. Anthony Hitchings

    Anthony Hitchings Active Member

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    we used in our Thanksgiving trip to and from the Tacoma area - it works real well.
     
  17. Econ

    Econ Active Member

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