Stepper is getting hot

Hello there,

i own a K40 machine and one of the two steppers (X-Axis) is getting very hot, even in idle. It is getting so hot, that you cant touch it longer than 1 or 2 seconds. I’ve done some research and found out that it is normal, that steppers can get to temperature 80 degress celsius above the room temperature. But why is it only one stepper that is getting so hot? The other one is at a normal temperatur all the time. I wouldn’t mind this problem if i wouldnt use some 3d printed parts that get in contact with the stepper. The PLA filament isnt that heat resistant and it wont keep its form through the heat…

Any ideas maybe?

Thanks in advance!

Sounds abnormal. Bad stepper drive or motor- or the drive is just set for the wrong current, that’s the first thing to check. Odd for this to be a fault that still runs ok. Normally a busted system will not move the axis or the axis just shakes.

Also the wiring needs to be correct on the stepper, but if it’s wrong I wouldn’t expect it to run.

That is, the common 4-wire stepper has 2 independent coils, “A” and “B”. It doesn’t really matter what you call a coil’s “+” or “-”. If you flip the wires on a coil, the motor will run backwards (which you can probably flip in the controller’s config), but flip the two A wires for each other along with both B wires and it will run the same direction.

The wrong thing would be hooking up one “A” coil wire and one “B” coil wire into the “A” output pair on the motor driver. But again, the motor should not move in that config.

Oh hey, could this be an 8-wire spit coil motor and the split coils are wired for series when the drive was set to a current intended for parallel? That would heat it up but continue to operate. Lots of 8-wire split coil 2-phase steppers around.

Swap the motors, if the X axis still gets hot then its an over current from the driver.
If not replace the motor.

The y axis motor has 2 shafts (left and right) and the x axis motor only has one. I cant dismount the shaft from the y motor because the chinese quality screws are broken… and the motor has no type nr. or anything else on it so i dont know which motor to buy.

I believe @paulcw was referring to swapping the wires. This can obviously create a crash-prone condition so I’d be very cautious if you’re to do this.

If the motors look the same (same physical size) you could do a voltage test.

When your system is activated, but idle, chances are the motors are energized. You can probe the motor wires with a DC volt meter and try different wires until you get a non-zero reading. Do the same with the other motor, even better with the same wire pair as the first motor. The two voltages should be similar.

Of course one motor is sized for only moving the laser body and the other motor is sized to move the laser body with its axis carriage (more mass). However it is common to just use identical sized motors for the economy of lower parts inventory costs.

Either way, the voltages should be close to each other and are a proxy for the motor current.

No not the wires, swap the actual motors, as stated, it will determine if its the driver or the motor at fault!
Motors are motors if they are the same its a simple way to start process of elimination , if i meant wires I would of said wires ! if after swapping the motors the problem exists in the same motor “POSITION” then it is an over current from the Diver.

It looks like after a quick google they are nema 17 motors, they are generally 0.9 steps have a look on ozznest and measure up the block size for comparison of dimension if the motors have no reference. after googling it does seem that the motors are not the greatest quality on the K40 and are prone to acting up. click technical specifications they have drawings and size references ! Also a forum here Stock K40 - Stepper motor failed - #5 by Dimitris_Galaktiou - Help - Maker Forums