What range of PWM fequency can control a shunt DC motor by using L298?

Discussion in 'The Projects Forum' started by wayne_lik, Mar 12, 2008.

  1. wayne_lik

    Thread Starter New Member

    Dec 17, 2007
    6
    0
    Actually i'm using L298 motor driver to control a shunt DC motor, and the PWM is generate by a PIC16F877A. the PWM frequency that i use is 244 hz but in this frequency the motor does move at all.

    so, i use a function geerator to as a PWM to drive the motor at below than 100hz te motor will only run?

    so, wat frequecy should i use and why when high frequency motor can't move only move at low frequency???

    can anyone help me pls???

    thx...
     
  2. rwmoekoe

    Active Member

    Mar 1, 2007
    172
    0
    i don't think higher frequencies can result in the inability to drive the motor when it can be driven at lower frequencies. higher freqs. only get the motor running better (smoother), provided that the wave is still representative in terms of power.

    from what you told, i thought maybe there was something wrong with the first circuit that supposed to deliver the pwm (including the pic).
     
  3. rwmoekoe

    Active Member

    Mar 1, 2007
    172
    0
    you can prove this using the function generator you've installed, by getting it working at higher freq., say 500hz or more.
     
  4. wayne_lik

    Thread Starter New Member

    Dec 17, 2007
    6
    0
    i have already using function generator input to the pin of enable of L298 motor driver.
    with certain frequency the motor will only run smooth but at high frequency the motor not response at all.....
     
  5. rwmoekoe

    Active Member

    Mar 1, 2007
    172
    0
    please post your circuit image. that way we can get down to it clearer
     
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