Hi there! I am rather a newbie at this and I was hoping I could find some answers to my question here on the forums. I have a Nema 17 stepper motor from Pololu (https://www.pololu.com/product/2267) that I am trying to drive with the DRV8825 (https://www.pololu.com/product/2133). I do not have the DRV8825 in my possession yet because it is in the middle of being delivered.
My first question is: is a potentiometer attached to the DRV8825 or not? The product page says, “adjustable current control lets you set the maximum current output with a potentiometer” and I was not sure if I would need to order a potentiometer separately.
My second question is: what kind of power source am I going to need to power the DRV8825 and run the stepper motor? I am a little bit confused because the stepper motor says each phase draws 1.7 A at 2.8 V. The stepper driver requires a voltage of 8.2 V to 45 V to operate. I have an adapter that converts 120V AC to 12V DC (2 A). Would I be able to use that adapter with a breadboard and feed the stepper driver. Then use the potentiometer to lower the current from 2 A to 1.7 A for the stepper motor.
There are clear instructions on the DRV8825 product page pololu.com/product/2133 for setting the winding current limit. Follow those carefully to set the winding current to about 1.5 amps/phase or less.
That 12V, 2A adapter may be sufficient to power the motor, especially if you set the current limit to less than 1.5 amps/phase. However, do not use a breadboard to make connections to motor. Breadboard contacts cannot handle that much current and will probably burn out. Instead, wire the motor leads directly to the motor terminals of the DRV8825. You can use jumper wires to pin terminals, or solder the wires directly to the holes on the board.
The current limiting potentiometer is located in the upper left corner of the DRV8825 carrier pictured below, so you would not need an external potentiometer.
The power supply you have should be fine, since its output is between the 8.2V and 45V operating voltage range of the DRV8825. You can see more about using a stepper motor with a higher voltage than it is rated for in the first FAQ on the Stepper motor product page. Like Jim mentioned, you should probably set the current limit on the DRV8825 to the 1.5A recommended maximum of the DRV8825 carrier board.
