Strange sound from stepper motor

Hi,

I have changed one of belts to GT2, re-flashed software (to V1), and have noticed interesting behavior… Y-stepper motor sometimes (not always) makes a sound like a small fan. It’s not moving, if I manually move bed in Y-direction back and forth, it stops. If I hit “reset”, it stops. It sounds like a laptop fan, very quiet, not really noticeable, but it exists until I either reset controller or move a bed. Anyone experienced something similar? I didn’t notice this behavior before last upgrade… Just afraid to burn a motor…

Sounds like your motor stalls.
Is the axis running freely?
Did you set the stepper drivers to 0.55V?
Did you set the correct steps/mm after updating the firmware?
Did you restore factory settings after flashing?
What Arduino Version did you use for flashing?

Sounds like you’re hearing the ‘chopper’ frequency of the stepper driver.

  1. I verified that when bed moves to “home” position, it still has a few millimeters to the end of the rods.
  2. Stepper drivers set to 0.55V (may be 0.54 or 0.56)
  3. Steps per millimeter for Y-axis are original 64.25 (I changed only X belt yet…)

Actually this makes another question… When using belt calculator, for T5 and 10-teeth pulley, it calculates it to 64 exact, while in the firmware it says 64.25… What should it be?

  1. Yes, I have loaded “factory EEPROM” and saved it back.
  2. Arduino… latest version.

Again, the sound is like “white noise” of a laptop. I didn’t even realize it’s coming from motors, until I hit a reset button…

So, if i get you correct, you have no problems with motor movement?

Then Paul is right. The higher you set the motor current, the more the coils will resonate at the chopper frequency.

Thanks. Again, I don’t think it’s a problem - motors are cold, drivers are cold (when I don’t print).

Do anyone else noticed, that if you power off K8200 (or reset the controller), some noises disappear?

That’s normal.
If you reset or power cycle the motors are initially off.
Same should appper if you press power off motors switch in repetier’s manual control.