Mosfets and Motors

Discussion in 'General Electronics Chat' started by bizzy, Mar 20, 2011.

  1. bizzy

    Thread Starter New Member

    Mar 20, 2011
    Good afternoon

    I am currently working on a pulse motor. I am usining a mosfet to try and pulse run a motor with a flyheel.
    The mosfet is allowing 12.5plus volts to pass but it is not turning the motor. The motor runs fine if I hook it up directly to the motor so I know the battery and motor are fine.
    The only other thing I can think of is that the motor is not getting enough amperage. And the only culperate I can find is the mosfet.
    Does any one know of a way to get the mosfet to allow more amperage to pass or know of another way to get the motor to pulse?
    Let me know
  2. Adjuster

    Well-Known Member

    Dec 26, 2010
    You need to provide more information, including a schematic of your set-up. Include details of the motor rating and FET type.

    In order for a MOSFET to provide adequate drive for the motor, it would need to have a low enough RDS(ON), and to receive an adequate gate drive voltage.

    If you are applying pulsed drive, it could be that the pulses are simply too short, so that the motor cannot respond to them.
  3. hobbyist

    Distinguished Member

    Aug 10, 2008
    First hook up your motor to the mosfet and its supply. Then manually apply a voltage signal to the gate of the mosfet, and see if the mosfet supplies the motor current.

    If it does, then lower the PWM frequency to a few hundred herts, and see if the motor responds, then from there work your way back up to higher frequency until the miotor drops out again.