I'm very new to all of this and with no real competence in electronics in general.
I've managed to screw up a stepper motor and I would like to know if anyone has an idea of what may cause symptoms like below, so I can figure out how I might have messed up so I won't do it again.
The circumstances
I've been testing out some old printer steppers (rated 24V, 600A) with the Arduino Uno and an Adafruit motor shield. I power the shield with an external 9 volt (5A) power supply (with the power jumper removed). They initially both worked fine, but suddenly - and I can't really make out when or what I did before - one of the motors started to behave weird.
The symptoms
The corrupt motor seem to spin in only one direction. This was clarified when I did a resistance/continuity test with the multimeter. The multimeter now shows continuity between all four pins, which I know it didn't do before. The drivers seems fine as the other motor runs fine on either connection
JestonLunnigan:
I've been testing out some old printer steppers (rated 24V, 600A) with the Arduino Uno and an Adafruit motor shield.
I doubt that they are 600 Amp.
There are two versions of that shield, and both are NOT suited to drive low impedance steppers.
The chips on those shields are brushed DC motor drivers.
Leo..
It is very unlikely that you damaged the motor. Printer steppers are high impedance and cannot be damaged by applying voltages less than the design voltage.
If a motor wire became disconnected while the setup is powered, you may have destroyed the motor driver.
Post links to all the parts, post a wiring diagram (hand drawn, not Fritzing), and your code, using code tags. See the hints in "How to use this forum".
Ok, so it turned out it was simply a matter of me not noticing that one of the motors was unipolar. Embarrasing, but that's a part of the journey I guess. I was probably fooled by the fact that I happened to run a sketch where a unipolar motor hooked up as a bipolar behaves somewhat similar to a bipolar motor, making me assume that everything was fine. I now hooked it up to a five pin cable and everything works as expected!
This thread may be scrapped, or left for facepalm material.