| 摘要 |
PURPOSE:To increase torque and the speed of a motor by stopping feed to A phase and B phase from a DC power only in a section, in which armature currents exceed a set value and are lowered up to a specified value, and discharging magnetic energy stored in an armature coil through a diode during stoppage. CONSTITUTION:When exciting currents exceed a set value by the reference voltage of a terminal 40, an output from an AND circuit 43a is brought to a low level because an output from an operational amplifier 40a is brought to the low level, and a transistor 20a is not conducted. Consequently, magnetic energy stored in an armature coil 17a is discharged through a diode 21a, a transistor 20b and a resistor 22a. When discharge currents are lowered up to a specified value, an output is returned to a high level by the hysteresis characteristics of the operational amplifier 40a, the transistors 20a, 20b are conducted again, and armature currents are increased. When discharge currents are elevated up to said set value, the output from the operational amplifier 40a is brought to the low level, the transistor 20a is changed into non-continuity, and armature currents are lowered. |
