| 摘要 |
PURPOSE:To save the resistor for limitting discharge and to reduce capacity loss by connecting a capasitor between the terminal on the normally closed contact of an operation switch and the AC input terminal of the second string of a three-phase full-wave rectifier. CONSTITUTION:The positive half-wave current from a single-phase AC source 1 passes through the normally open contact 2-1 which is closed and the exciting current for holding is supplied through a capacitor 4, a diode 5-2, an operation coil 3 and a diode 5-6. Also, the negative half-wave current of the single-phase AC source 1 is supplied through a diode 5-3, the operation coil 3, a diode 5-5, the capacitor 4 and the normally open contact 2-1 which is closed. In this case, the exciting current is limitted the impedance value of the capacitor 4 and is made to be least required for maintaining the attracting state of an iron core. Accordingly, the capacitor 4 which functions as a series impedance generates only a reactive power and capacity loss is not caused. |
