Turning a hairdryer into a COOL blower

Discussion in 'General Electronics Chat' started by StephenDJ, Apr 6, 2009.

  1. StephenDJ

    Thread Starter Active Member

    May 31, 2008
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    Ok, here's what I'm trying to do...

    I'm building a homebrew fresh air device, and need to install a switch in this simple hairdryer that will switch off the heating elements. If there's anyway to do it, this would be cheaper than having to buy a blower.

    I've opened the thing up, followed the wires, and drawn the schematic (below) from what I see. Could anyone explain to me how this thing works? Where in the circuit to install a switch?
     
    Last edited: Apr 6, 2009
  2. Mike2545

    Active Member

    Mar 26, 2009
    116
    3
    Cant quite make out that switch you got drawn there. But you may be able to put another switch in just to turn on the motor and bypass the heater elements.

    By the way, blow dryers are not designed for continual use. I'll bet If you run the thing for 1 hour straight it will burn up the motor, even without the heater elements on.
     
  3. StephenDJ

    Thread Starter Active Member

    May 31, 2008
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    The switch that is already installed is essentially a double pole, triple throw slide switch that connects only two adjacent contacts in each row at a time (on each the two poles simultaneously). For example, if the contacts were numbered 1-4 (pole 1), 5-8 (pole 2), then when switch is in the left most of the 3 possible positions, contact 1 would be connected to 2, and 5 would be connected to 6. The middle possition is OFF.
     
  4. Mike2545

    Active Member

    Mar 26, 2009
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    Still, why would you be useing a hair dryer for freshair? Use a fan or open a window.
     
  5. b.shahvir

    Active Member

    Jan 6, 2009
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    Dear Stephen,

    From the looks of the ckt. diag., the heater elements have a dual role, as in it acts as a current limiting resistor in series with the DC motor which I presume must be rated at approx. about 3VDC. Hence,in my opinion, if the heaters are bypassed, then 120VAC will directly feed the rectifier ckt. and burn out the motor. :eek:

    Regards,
    Shahvir
     
  6. StephenDJ

    Thread Starter Active Member

    May 31, 2008
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    Because that is the only way I have of getting the air blown into the 1 1/4" I.D. clear tubing.
     
  7. StephenDJ

    Thread Starter Active Member

    May 31, 2008
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    Is there way to substitue another resistance in place of the heaters?
     
  8. b.shahvir

    Active Member

    Jan 6, 2009
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    Yes, but the resistance should not come in contact with the air blast from the dryer fan as it will then heat up the air again defeating your purpose.

    You can also go for an inductor or a capacitor of suitable rating for current limiting purpose on AC side, i.e before the rectifier section. It has an added advantage in that it does not emit heat as compared to the series resistance. However, the design of current limiting components should be of suitable rating or else it could pose a severe electrical hazard and safety issue! :eek:

    Regards,
    Shahvir
     
  9. StephenDJ

    Thread Starter Active Member

    May 31, 2008
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    Thanks! I like your suggestion. I 'll have to think on this a while to understand it.
     
  10. Mike2545

    Active Member

    Mar 26, 2009
    116
    3
    Or use a 3 VDCwall transformer
     
  11. nucleargungus

    Member

    Apr 6, 2009
    23
    1
    use a shop vac open up the blower port on the back....
     
  12. Mike2545

    Active Member

    Mar 26, 2009
    116
    3
    What on earth do you need fresh air blowing in a 1 1/4" tube for?

    Underground tunneling? ;)

    Prisoner in a box in the crawl space? :eek:

    Clandestine grow lab? :cool:

    Home style airplane seating? :p

    Really big party balloons? :D
     
  13. inventorjack

    Member

    Apr 4, 2009
    14
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    Heh, now you've got me curious as well :)
     
  14. Mike2545

    Active Member

    Mar 26, 2009
    116
    3
    And another thing, why does the tubing need to be clear?
     
  15. b.shahvir

    Active Member

    Jan 6, 2009
    444
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    Excellent idea! but again the transormer voltage and current ratings will have to match that of the motor. If motor is considered to be rated at 3VDC, then Xmer should be of lower secondary output voltage as after rectification the DC voltage across the motor is equal to the peak value of Xmer sec. RMS AC voltage. Gud Luck :)

    Regards,
    Shahvir
     
  16. StephenDJ

    Thread Starter Active Member

    May 31, 2008
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  17. b.shahvir

    Active Member

    Jan 6, 2009
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    I think this is a much better option then, keeping in mind the air quantity required ;)
     
  18. Mike2545

    Active Member

    Mar 26, 2009
    116
    3
     
  19. b.shahvir

    Active Member

    Jan 6, 2009
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  20. Mike2545

    Active Member

    Mar 26, 2009
    116
    3
    If you agree with me, then what is this about?:confused::confused:
     
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