When stepping motor rotation, the motor of each phase winding inductance will form a reverse electromotive force; The higher the frequency, the greater the back emf. Under the function of it, the motor with frequency (Or speed)The phase current decreases, which leads to torque decline. the main products: stepper motor, brushless motor, servo motor, stepping motor drive, brake motor, linear motor and other kinds of models of the stepper motor, welcome to inquire. Telephone: