I am learning about stepper motors and i have the following question. Let's say i have a bipolar, 2 phases, NEMA34 with a 5A rated current. I am using a driver capable of delivering 5Amps or 2Amps at a voltage between 24-80V. How will affect these different current values the behaviour of my stepper motor? First i set the current limit to 5A and then to 2A. In conclusion, how does adjusting the current limit of my driver affect the stepper motor?
Reducing the current of a stepper motor will not reduce its precision but it will reduce its "holding torque" feature. The holding torque is the ability of the stepper motor to keep its position when a torque is applied on its axis of rotation. If we take this one for example, it is not explicit but the max holding torque (4.8 Nm) is directly linked to the rated current per phase (6.0 A). I don't remember the exact equation linking the holding torque to the amperage but if you reduce the current, the holding torque will also decrease. If you intend to use a stepper motor not only to precisely move but also to stay in place when an external torque is applied (like holding a weight), you should take care of the current you are providing to the stepper motor.