In order for the electric current which flows to the aforementioned exciting winding on the basis of the measurable quantity of the electric current

摘要

PROBLEM TO BE SOLVED: To estimate the class of a stepping motor which is driven by a drive unit for a stepping motor.;SOLUTION: In condition that the duty of PWM control is kept constant and that a phase switching circuit 3 is activated, specified voltage is applied from a voltage adjusting circuit 9 to an exciting coil. The process of the drop of the specified voltage applied to the exciting coil is sampled until a predetermined time passes, and the dropped voltages are integrated and the integral value is measured. The duty of the PWM control signal is adjusted so that the coil current flowing to the exciting coil becomes a rated value after finish of the sampling, and the output voltage of the above adjusting circuit 9 when the coil current is at the above rated value is measured. The unknown class of the stepping motor is estimated based on the integral value and the output voltage.;COPYRIGHT: (C)2007,JPO&INPIT