| 摘要 |
PURPOSE:To eliminte the starting current at the time of throwing a power source in a controlling transistor by connecting a resistor in parallel with the transistor and interrupting the transistor for predetermined time from the time of throwing the power source. CONSTITUTION:When a power source is energized, a time transistor 14 determined by the time constant of the time constant circuit having a capacitor 11 and resistor 12, 13 is conducted. Since a transistor 17 is thus conducted, controlling transistors 2, 3 connected in series with an armature coil 1 are interrupted, and the armature current will flow the resistor 5 connected in parallel with the transistors 2, 3. After a predetermined time is elapsed, the transistors 14, 17 are interrupted, the transistors 2, 3 are thereafter controlled by the output of an inversion amplifier 6, thereby controlling the revolution frequency of the DC motor to a set value. |
