Stepper Motor drawing less current from DRV8825

Support Motor controllers/drivers and motors
1

Hi,

We are using a stepper motor (Pollulu 1209) which has a rated voltage of 2.7V and resistance of 2.7 ohms. This means that the rated current is 1 A. We have also set the current limit of the DRV8825 motor driver to 1A. We are running the motor with a 24V power supply. On the multimeter, the current value doesn’t go beyond 250 mA. Clearly, something is not right since the motor should consume more current. Can someone help us solve this? Is there a particular way of measuring the current of the system?

In addition to using a multimeter, we added a 1-ohm resistor in series with the system and measured voltage across it using an oscilloscope. Even that is giving similar results that is low current. What could be the reason for this?

Why are we getting a low current reading?

2

Hello.

Current limiting stepper drivers like the one on our DRV8825 board behave like a switching regulator and it is generally expected that the output current will be different from the input current since the input voltage to the board and effective output voltage to the two motor coils are different. We have some explanation of why this is the case in our FAQs for the motor driver and stepper motor you mentioned. Are you having a problem with the motors moving?

-Nathan