DC Motor L293D Interfacing

Discussion in 'General Electronics Chat' started by ActivePower, Jul 18, 2012.

  1. ActivePower

    Thread Starter Active Member

    Mar 15, 2012
    Well, to begin with it is my fault to have bought a L293D motor driver instead of a L293 without knowing the current ratings of the ICs. But since I have one now, I have a few questions regarding motors and their drivers:

    1. The motor is rated simply at 150 rpm and 12V with no current rating whatsoever (it is a local make). I checked the coil resistance to be about 10.1 Ω. Which gives an approx current rating at 1.18 A. Can this be nearly/less than the nominal rating of the motor?

    2. The L293D is rated for a continuous supply of 600 mA and a peak supply of 1.2 A. Is the peak current rating given for worst cases (loads) which may occur occasionally?

    3. Can I safely use the driver for running my motor at no load condition just to test out my program? I have not worked with motors and stuff in the past much, so forgive me for my ignorance but I think motor current is quite low at no-load conditions (and in the within the driver capability).
    But I want to be sure beforehand so that I don't burn up the IC the first time around.

    4. Any good sources to read about H-bridge motor drivers?
  2. DigitalReaper


    Aug 7, 2010
    The easiest way to find out would be to try it without the bridge. Power the motor from your 12v supply and measure the current.

    The winding resistance only tells you the maximum current draw possible (ie. when it's stalled). My (probably poor) understanding of it is that the motor also acts as a generator when spinning producing some back EMF that resists the flow of current.