DRV-8825 with unknown stepper motors

I’ve been experimenting with your DRV-8825 carriers and they works great! I have a box of assorted surplus stepper motors that I have not been able to identify other than that they are bi-polar. They range from very small CD tray motors to medium size laser printer motors. I’ve been able to get them all working using the DRV-8825. I have 2 questions regarding voltage and current.

  1. I’ve tried voltage settings between 10V and 24V and it does not seem to make a difference. Since the driver is constant current, I assume it steps down the voltage as necessary. Therefore, does it matter what voltage you choose?
  2. For current, I’ve been starting low and then increasing it until I get too much heat or any noise while idle. For heat I’ve been using the 5 second rule (I can comfortably touch the stepper and the DRV8925 for 5 seconds.) Does this sound like a prudent approach? Are there more scientific methods?


You are correct, since the stepper motor driver limits the current to the stepper motor, so long as this current limit is appropriately set, there is a wide ranges of voltages that can be used to supply power to the stepper motor. Higher voltages allow current to ramp up faster, which can be beneficial for things like trying to run at high speed or with large loads. You can learn more about this under the FAQs tab of any of our stepper motor product pages, like this one.

We do not have any specific recommendations for testing unidentified stepper motors, but an incremental approach like what you are trying seems reasonable.