Requirements of PWM to drive a motor

Discussion in 'General Electronics Chat' started by richiechen, Jun 7, 2012.

  1. richiechen

    Thread Starter Member

    Jan 1, 2012
    Hi everyone

    I have made a driver board with l298n.
    However, the motor can only be drived when PWM ratio is higher than 55/100.

    Below 55/100, the motor will only make "beee" noises without moving.

    Is it normal?
    Is it caused by bad driver or bad motor?

    Thank you very much.

    Best regards
  2. shortbus

    AAC Fanatic!

    Sep 30, 2009
    You don't give enough information. :) What type motor? What is the PWM circuit? If the switching 'carrier frequency' isn't high enough (around 20,000 hZ) it won't work at a low duty cycle.