| 摘要 |
PURPOSE:To reduce the consumption of powder by electrifying between diode, resistor series circuit, and thyristor only during the time to give an ignition command from the zero-voltage point of AC power source to the thyristor of control rectifying circuit. CONSTITUTION:At the both ends of the resistor 141, a pulse voltage synchronized with the zero point of the power source 45 occurs, and the flip-flop circuit consisting of the NOR circuits 113 and 114 receives the zero point detection pulse as set signal and the ignition pulse synchronous signal of the thyristors 41A and 41B composing a 2-phase half-wave phase controlling and rectifying circuit for the separately excited field 5 of DC generator as reset signal. Thus, during the time that the thyristor 41A or the thyristor 41B is electrified between the negative or positive half- cycle of the power source 45, the transistor 101 is not electrified and thus no current flows in the negative bias resistor 43B or 43A. In consequence, no unnecessary circulating current flows in resistor and therefore power consumed by resistor can be reduced. |
