Because this is a low-voltage, low-inductance motor, it must be driven by a (current-limiting driver). Connecting it directly to a constant DC voltage source equal to its rated voltage (without current limiting) will damage the motor.
Elara’s hands trembled. She looked at the small, unassuming motor sitting in the evidence locker camera feed on her second monitor. It was the size of a spice jar. Black casing. Four thin wires. It looked like something from a 3D printer. bj42d15 26v10 stepper motor datasheet