Step Motor Kaput?

[sinclair 0]

Ultimaker Original. During the first print after I had tightened all screws and pulleys and about 30 minutes into print the X axis stopped working. The motor was warm to touch as was the Y motor at this time.

After doing a bit of reading on motor-related posts I have attempted to: adjust x, y and z stop clips; reduce power in the stepper driver (blue chip; 1/4 turn clockwise); and check and retighten all nuts and bolts on the pulleys and axis bars. I did change X with Y stepper driver inputs, and indeed the Y axis motor still worked and the X did not - hence I suspect an X axis motor failure. Is there an easy way to test the X motor function individually and directly? Or is it just a matter of buying a new motor to see if the original was burnt out.

How might one avoid a similar problem with the Y and Z motors in the future?

Much appreciated.

 

[gr5 1,256]

Swapping cables is the best way to test the motor.

However stepper motors are incredibly tough and even if it was boiling water on the surface it can probably survive even that. I believe the max operating temp is either 70C or 80C. That's very very hot. I doubt yours got that hot but maybe it did.

Messing with the stepper driver current is very dangerous. The most common result by far is to destroy the stepper driver. Those stepper drivers are delicate. The steppers are not. You can google "pololu" if you want to buy more. They are not expensive. The "clockwise" versus "anticlockwise" issue: some stepper drivers are backwards from others. Did you check the photo that shows the 5 types from ultimaker? And make sure you got the correct direction?

If you turn the current up too high or too low the stepper motors don't work very well and can make strange noises. But they don't often get damaged.

 

[sinclair 0]

I have returned the stepper driver to its original settings (I have the blue chips as per the photo and had turned it 'clockwise' (to lower the current) initially). However I have no movement (rotation) with the Y axis motor regardless of the stepper driver into which it is plugged. I therefore suspect (hope) that it is just the motor that has burned out (albeit I did not smell any strange odors at any time when it was up and running and it did not feel very hot). Any other tricks or thoughts that I might try prior to ordering another motor to verify that it is indeed just the motor? Much appreciated.

 

[gr5 1,256]

However I have no movement (rotation) with the Y axis motor regardless of the stepper driver into which it is plugged

 

These things are tough as hell so it's still more likely a bad wire. Did the wire get pinched? Can you find an ohm-meter and measure the continuity of all 4 wires from the motor to the connector? I guess you'd have to take the stepper itself apart.

If you cut power and push the head back and forth in X only you should see the ulticontroller "light up". Does the same thing happen in Y mode? If only 2 of the wires are working I would guess that it lights up but you have to push it a little faster than in X.

 

[gr5 1,256]

Oh - you should be able to check the continuity of the stepper motor wiring at the connector. Each pair of twisted wires should be the same resistance. And a pretty low value - I would guess 100 ohms? Just pulling that number out of nowhere but the EE in me says somewhere from 10 ohms to 1000 ohms.

 

[sinclair 0]

Thank you for your insightful thoughts. So I took off the stepper motor to check the wiring and yeeks! the pulley fell off - yes all it was was a loose pulley screw. Tightened it up and everything is hunky dory. Retightened the other motor pulleys as well. Much appreciated.