| 摘要 |
PURPOSE: To reduce vibration and noise by stepping the rotor to a position of a step angle corresponding to a phase angle determined by the exciting current under two-phase exciting state during low speed driving. CONSTITUTION: An exciting circuit 3 feeds an exciting current, having a magnitude set at a current set circuit 1, to a one-phase or two-phase exciting coil 5A selected by a selection circuit 2. For example, phase A is fed with an exciting current of second current value (1') whereas phase B is fed with an exciting current of fourth current value (1'). At that time, an exciting vector has a phase angleθ1 equal to (1'). Phase angle of the exciting vector is set by the resistance of a group of series resistors R1-R5 and R6-R10. Subsequently, the exciting current of phase A has a fourth value of (3') whereas the exciting current of phase B has the second value of (3'). At that time, the phase angleθ5 of the exciting vector is set at 3'. Thereafter, the exciting current of phase B has the first current value of B and the exciting vector becomes B which is shifted by 90 deg. from phase A. |
