Wheelchair Motor Controller

Discussion in 'The Projects Forum' started by chrismalyon, Jun 1, 2011.

  1. chrismalyon

    Thread Starter New Member

    May 31, 2011
    I am trying to build a circuit what will drive two 24v 9amp wheelchair motors. I want to supply a PWM input from an arduino to control the speed of each motor. I have built a similar project using the L298N to drive a small toy tank around but the motors were alot smaller and didnt draw as much power. Ideally I want a way i can just scale this up to drive the larger motors.

    Any ideas would be good

  2. Patman

    New Member

    Sep 16, 2010
    I'm actually thinking of doing the exact same thing! I've got two really nice 24v motors in great shape. Grease is still looking good, windings are healthy. They're from a junked wheelchair, complete with battery pack, (inop) charger, and control unit joystick.

    I'm hoping to build a tracked tank vehicle using the motors and two lead-acid batteries. My idea is to make a really beefy H-bridge with some IR540N MOSFETs for drive controls, and two more MOSFETs for the electric brake. PWM controls should be sufficient for each one, methinks, but I'm open to ideas just as you are.
  3. wayneh


    Sep 9, 2010
    That MOSFET's current rating might be OK, but I'd go larger, up to 4X or more times the anticipated continuous current. (And don't forget startup.) There's so little increase in cost to upgrade to a beefier MOSFET. There are many reasons to over-specify; for one thing it compensates for imperfections in the MOSFET driver circuitry, where the FET might not always be perfectly on or off but somewhere in between where it will generate unexpected heat. Again the 540 will probably be fine with a nice heat sink and attention given to the driver design. I'm just sayin'.

    You'll find lots of H-bridge experts here, but it is summertime in the northern hemisphere so they may be distracted by other interests. ;)
  4. shortbus

    AAC Fanatic!

    Sep 30, 2009
  5. wayneh


    Sep 9, 2010
    Here's one: Try posting the circuit you'd like to scale up. Might help stimulate ideas.