| 摘要 |
PURPOSE:To smoothly start a commutator motor with a simple structure by using a positive temperature coefficient thermosensitive resistor for one of a voltage dividing resistor for specifying the charging current of an integrating capacitor for triggering a switching element. CONSTITUTION:When a switch 14 is closed, a resistor 26 has a low resistance value. Accordingly, a potential of a combined voltage point A decreases, and the voltage rise of a capacitor 30 is delayed. Thus, since the conduction rate of a thyristor 16 decreases, a current flowed to an armature 10 and a field 12 decreases. Then, as the resistance value increases due to the self-heating of the resistor 26, the potential at a point A increases, the conduction rate of a triac increases, and an armature current increases. As a result, the armature 10 is smoothly accelerated. |
