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12v Fan Reduce speed in every minute interval using 555 timer.

Discussion in 'General Electronics Discussion' started by Genrick Son, Nov 5, 2015.

  1. Genrick Son

    Genrick Son

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    Nov 5, 2015
    Hi guys im pretty new to electronics,

    I know its to much , Im looking for a simple schematic design about 12v fan that can automaticaly reduce its speed in a minute interval . From 100% speed to 60% to 30% until zero.

    regards genrick son,
     
  2. Alec_t

    Alec_t

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    Jul 7, 2015
    Welcome to EP!
    Does the fan have a speed-control input? Model/specification?
     
  3. Genrick Son

    Genrick Son

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    Nov 5, 2015
    No sir , just a normal DC fan .
     
  4. nepow

    nepow

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    Jul 18, 2011
    Do's this nead to happenevery time the fan switches on? and how accurate does the timing need to be.
     
  5. AnalogKid

    AnalogKid

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    Jun 10, 2015
    To go from full speed to off in 1 minute you gradually reduce the energy available to the fan.

    There are two basic ways, analog and digital. Analog means a voltage regulator where either a control voltage is decreased slowly or the negative feedback that establishes the output value is changed slowly. Digital usually means pulse width modulation (PWM), where the duty cycle of the 12 V pulses is changed slowly from 99% to 1%. Note that normal brushless DC (BLDC) fans will not run at very slow speeds, so no matter which method you use, the fan might slow down to maybe 20-25% and then just stop.

    What kinds of parts and test equipment do you have available to you, what is your build and test skill set, etc. Which method sounds like something you want to try?

    ak
     
  6. Genrick Son

    Genrick Son

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    Nov 5, 2015
    Yes sir , every 6 minutes or less , 4 intervals which the last one is turn off .

    thanks for fast replies
     
    Last edited: Nov 5, 2015
  7. Genrick Son

    Genrick Son

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    Nov 5, 2015


    Thermistor, LM35, thermocouple , Im still new to electronics sir , we would like to use it in our project which the fan will use as a blower to cook rice .. Can you make a simple schematic about this sir ? which probably every 6 minutes the blower changes its speed in 4 stages .. at the last stage it is now turn off .
     
  8. garublador

    garublador

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    Oct 14, 2014
    This may be an instance where a simple microprocessor might be the best solution.
     
  9. Genrick Son

    Genrick Son

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    Nov 5, 2015
    can you make a simple schematic about it sir ?
     
  10. Colin Mitchell

    Colin Mitchell

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    Aug 31, 2014
    Your requirement is very complex and beyond a beginner.
     
  11. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    I googled "Normal DC Fan" but didn't get any hits. My guess is there's no such animal. Perhaps if I try "Abnormal DC Fan" it will point me to a normal one.:D

    Chris
     
  12. Colin Mitchell

    Colin Mitchell

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    Aug 31, 2014
    He is possibly talking about the highly sophisticated brushless DC motor.
     
  13. AnalogKid

    AnalogKid

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    Jun 10, 2015
    Really? We go through a few thousand a year and they're pretty much dumb as dishwater.

    ak
     
    CDRIVE likes this.
  14. Colin Mitchell

    Colin Mitchell

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    Aug 31, 2014
    I have explained how they work on my website and you would still not comprehend their operation.
    They are the most advanced DC motor. Their operation is brilliant and it is only through the advent of the HALL EFFECT device that they were able to work.

    Explain to me the simplest question: How do they start to rotate?
     
  15. thaers3d

    thaers3d

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    Nov 7, 2015
  16. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    I don't think there's any maybe about it. ;) It will be a dirt simple circuit for a PMDCM (Permanent Magnet DC Motor) but he needs to start by selecting the motor/fan he's going to use and post the motor specs, so we can design around it.

    Chris
     
  17. AnalogKid

    AnalogKid

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    Jun 10, 2015
    A side question - did you consider, for even one millisecond, including a link?

    ak
     
    CDRIVE likes this.
  18. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    The reason you missed it is because you're not psychic like me. On the other hand the OP can click on Collin's profile. This should take him to all of Collin's posts where he rarely fails to post anything but the link. :rolleyes:

    Chris
     
  19. AnalogKid

    AnalogKid

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    OTOOH, the OP has a total of 7 posts, 5 in this thread. If he is as new to forums as he is to electronics, he would need to read your mind in order to read Colin's. Double scarey.

    ak
     
    CDRIVE likes this.
  20. CDRIVE

    CDRIVE Hauling 10' pipe on a Trek Shift3

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    Ha, not as scary as my nephew Marty's mind! :p

    Chris
     
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