Y stepper stopped working

Everything has been working pretty well. Got things squared up nicely and have been cutting steadily. But suddenly the “B” stepper on the Y axis stopped working. I’ve checked continuity on all the wires. If I plug the Y connector into the X port on the Ramb0, the behavior is the same. The controller side moves but the outboard side does not. If I plug the X connector into the Y port, it moves normally. The two pairs on the non-working stepper show continuity. Does this mean the stepper is burned out? I see Ryan is sold out of steppers. I don’t see a matching motor on Amazon. There is one that has 84 ozin but is only rated 2 amp instead of 4. I don’t see any 4 amp steppers. Suggestions? Thanks in advance.

The resistance on the coils should be like 4ohms or something really small like that. It might be small enough for the beeper function on a multi meter to still trigger.

If you short one of the coils, it should increase the resistance on the motor. So if you disconnect it, and twist it with your hand, it should spin freely. If you close the circuit on one of the coils, it should have some more resistance (I’m trying to come up with an example of how much resistance it is, but it should be obvious. Try a known good motor to compare). You can test both coils that way.

I would be pretty shocked that it died in service. They are pretty bullet proof. And since you’re wired in series, the only way it could break and the other motor would still work is if there was a short across the coil, and the current wasn’t flowing into the motor anymore.

When you checked continuity of the wires, did you make sure they weren’t shorted to each other? Did you make sure there was no continuity between the wires? Unlike motors, wires fail all the time.

Well Jeffe, thanks to you I got it going. In the process of checking the coils I decided I needed to remove the belt to feel the resistance. That allowed me to notice THE DADGUM PULLY WAS SPINNING! Tighten the set screws and back in business. After ruining $60 of 3/4" Starboard sheet. These machines really have a way to make me feel dumb. :slight_smile:

I always forget that…

Tom S is live building and he just mentioned that the pulleys could use locktite on the set screws.