CORRECTING METHOD FOR ERROR OF ROTARY ANGLE OF STEP MOTOR

摘要

PURPOSE:To reduce the error of a rotary angle by driving a step motor by polyphase excitation and regulating the exciting current or applied voltage of each phase coil so that the magnitude of the torques generated in polyphases become equal. CONSTITUTION:A step motor M is driven by 2-phase excitation via 4-phase coils A-D. Regulating resistors Ra-Rd are connected in series in the respective phases, transistors Tra Trd are connected in series with the resistors Ra-Rd, and flywheel diodes Da-Dd are provided. The exciting currents are altered to equalize the torques in the respective phases by regulating the resistors Ra-Rd. Similar effect can also be obtained by varying the applied voltages to the respective phases.