Mosfet pwm

Discussion in 'General Electronics Chat' started by domingojordan, Aug 14, 2014.

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  1. domingojordan

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    Aug 11, 2014
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    Last edited by a moderator: Aug 15, 2014
  2. jpanhalt

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    Jan 18, 2008
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    That can happen if it is hooked up wrong.

    Can you show us how you hooked it up?

    John
     
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  3. alfacliff

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    Dec 13, 2013
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    if it works for a while, then fries, is the mosfet rated high enough?
     
  4. MagicMatt

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    Sep 30, 2013
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    Do you have a protection diode? I fried one of my MOSFETs that way... lesson learned. :)
     
  5. MikeML

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    What is the motor voltage?
    Motor Current?
    What drives the FET?
    What is the PWM frequency?
    Is the FET bolted to a heatsink?
     
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  6. ScottWang

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    Aug 23, 2012
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    Post your circuit and the others as Mike ML mentioned.
     
  7. b1u3sf4n09

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    May 23, 2014
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    Also, did you size the mosfet for the inrush current or the running current? Motors pull a high initial current when they are building their magnetic field on startup. I've seen it burn up solid state relays, so it's something to keep in mind.
     
  8. domingojordan

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    Aug 11, 2014
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  9. bertus

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    Hello,

    I have merged the threads.
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  10. domingojordan

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    Aug 11, 2014
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    I need some help to figure out why i keep frying a mosfet. belove you will find a striped out motor control circuitry that i want to use to control the speed of a brushed motor. the motor rating is as follow: Brushed motor rated 120vac 12amps 1400w 50/60hz. The circuit start working at a low pwm pulse( analogWrite(pinNum, 20) ). I works slow but it is a litle noicy. When i increase the pwm pulse it snaps the mosfet and the motor start working at full speed and it gets wery hot in a short time. I had run the motor with a full motor controller circuitry that has it is own controller chip and the motor runs fine. I can pwm that circuitry with my controller at any pwm pulse. I want to pwm the mosfet gate and be able to control the speed of my motor. below are both circuitris the full motor control and the striped out version. I believe that some how i need to limit the current that the motor is getting because when i use the full circuitry the motor does not get hot and it runs smooth and i can controll the speed. I am not very electronic involved person but I am a quick learner.

    [​IMG]




    [​IMG]
     
  11. ScottWang

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    Aug 23, 2012
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    What is the type number of mosfet that you used?
     
  12. bertus

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    Hello,

    I am closing this thread as it violates AAC policy and/or safety issues.

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