motor speed controller with a musfet

Discussion in 'General Electronics Chat' started by domingojordan, Aug 17, 2014.

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  1. domingojordan

    Thread Starter New Member

    Aug 11, 2014
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    I used the mc2100 motor controller with a 120VAC 12A 1400W brush motor and works fine and smooth. This controller circuit was designed for the treadmill industry and does not fit my needs 100% and I will like to modify it.
    I want to implement what this controller does by PWM its mosfet with an arduino...
    At the beginning, I test running the motor with the rectify and filter AC but the motor does not run happy. It gets noise and very hot instantly. I tested it with the controller and it works really well. I concluded that somehow the controller limits the voltage and manage the current that the mosfet provides to the motor. This is where i need help to figure out how can i do the voltage limiting and the managing of the current with an arduino.
    The full circuit schematic is here: http://www.mikeamick.com/misc/MC2100_rev_engrd.pdf
    The strip out version is this: http://oi61.tinypic.com/e710sh.jpg

    I tested the stripped out version and it works with a low PWM frequency but it makes some noise. When the frequency is increased it snap the mosfet and the mosfet gets damage and starts to conduct 100% and the motor stars to run fast and gets really hot instantly.
     
    Last edited: Aug 17, 2014
  2. MaxHeadRoom

    Expert

    Jul 18, 2013
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    What PWM frequency are you using, I have not found the need to go above 4 to 5Khz based on the Microchip recommendation.
    Max.
     
  3. crutschow

    Expert

    Mar 14, 2008
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    Do you have the indicated diode connected across the motor?
     
  4. domingojordan

    Thread Starter New Member

    Aug 11, 2014
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    The instruction analogWrite in the arduino uses a frequency of 480 hz i belive.

    Yes, you can check the the striped out schematic, it shows the dio.

    Yes, you can check the the striped out schematic, it shows the diode.
     
    Last edited by a moderator: Aug 17, 2014
  5. MaxHeadRoom

    Expert

    Jul 18, 2013
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    Anything below 4khz you can expect to experience switching noise.
    Max.
     
  6. ronv

    AAC Fanatic!

    Nov 12, 2008
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    The mos fet is not a logic level fet. It is not fully on with the 5 volts from the logic. Use the 10 volt zener like the whole circuit.
    Ooops that may not work without a level shift from the 5 volt micro.
     
    Last edited: Aug 17, 2014
  7. bertus

    Administrator

    Apr 5, 2008
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