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Stepper motor holds at full current and makes noise, smooth otherwise

Hello,

I have the following:

EasyDriver stepper motor driver

Bi-Polar stepper motor 6 wire

I am using Red/White and Yellow/Black, which means I'm using half coil.  My understanding is this allows me to use the full current (and presumably have more holding strength).

Anyhow I have it wired up and everything works great once I tweaked the current output and delay between steps.  I see my benchtop supply shows something along the lines of 200ma while the unit is in motion against any force - and it holds up very well against my hand trying to slow the motor.  However, when the unit is stopped and simply holding (no pulses being sent to the motordriver) the current jumps to 500ma and the unit makes audable noises (it vibrates a little).  I can fix this by sleeping the driver but then there is no current supplied and holding torque.

I assume this is not normal, and I was wondering if anyone had some insight?  I don't want to just play around with the wiring w/o understanding the issue as I only have 1 motor right now!

thank

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That's pretty cool to think about.  Thanks guys!

If your motor is producing noise then most likely it's because the power to the motor is noisey. This could be due to poor regulation or switching from your power supply / stepper controller.

Basically your motor will behave like a speaker. This effect is often used by programmable motor controllers to generate audible beeps when you are programming them.

I'll buy that it's stupid and just uses full current vs when it's moving it's pulsing so it used less current -- but this doesn't explain the sound and vibration... any idea? thanks

stepper driver chips that have idle current reduction. At a guess, your idle current draw is what is to be expected.