| 摘要 |
PURPOSE:To prevent a deceleration overcurrent from generating by replacing the detection speed of a motor with a speed reference when a speed control system is utilized. CONSTITUTION:A field switching circuit 30 detects the polarity of a current reference signal IREF. A field current reference setter 20 inverts the polarity of a field current reference signal IFREF by an output signal from the circuit 30. A field current switching circuit 31 detects the switching of a field current by an output signal from a field current detector 22. A speed reference signal SREF from a speed reference holding period speed reference setter 2 is held simultaneously upon starting of switching the field by the output signal of an AND circuit 42. When the switching of the field is completed, the signal SREF is replaced from the output signal from the setter 2 to a speed detection signal SFDB by the output signal of an AND circuit 41. |
