Re: [SeattleRobotics] Do I have a damaged motor?
- The wheel attached to the suspect motor is much harder to turn by hand than the known good motor. However, I haven't tried the other steps you suggested.
I ordered two replacement motors from Acroname last night. I'm pretty sure (though not 100%) that the suspect motor is bad.
On Wed, 18 Aug 2010 21:19:11 -0700
Wim Lewis <wiml@...> wrote:
> Hmm, your troubleshooting steps all sound good to me.
> There could be a mechanical problem, either inside the motor, or perhaps
> the wheel is dragging against something. So the motor might not have
> enough torque to turn with the amount of current supplied by the motor
> driver, but when you connect it directly to the voltage regulator
> perhaps it supplies enough current to overcome the extra friction.
> A couple of ideas you could try:
> - Turn the wheels by hand and see if the troublesome motor is noticeably
> harder to turn. Do this with the wire disconnected from the motor so
> that motor braking doesn't complicate things.
> - Measure the resistance of the motor itself, see if it has about the
> same resistance as its counterpart. Maybe it has a bad connection
> internally. OTOH, small DC motors sometimes have kind of irregular
> resistance because their brushes don't make perfect contact, so this
> isn't a really conclusive test.
> - Measure the current going through each motor when the robot is trying
> to turn it. If the non-moving motor has much higher current than the
> moving motor, it's probably stalled (suggesting it's a mechanical
> problem). If it has much lower current, then there's probably some
> electrical problem.
> Visit the SRS Website at http://www.seattlerobotics.orgYahoo! Groups Links
Jason Hsu, embedded engineer, Linux user <jhsu802701@...>