| 摘要 |
PURPOSE:To enhance the reliability of a charging circuit by charging under the control of a pair of parallel thyristors, and interrupting thyristors of other parallel pair at the overcharging time to stop charging, thereby eliminating the heat generation and the deterioration of an element. CONSTITUTION:A commercial power source 10 is connected to the primary winding 14 of a transformer 12. The transformer 12 has two secondary windings 16, 18. The secondary winding 16 is connected to the connecting point of thyristors 22, 24 in a thyristor bridge 20 and to the connecting point of thyristors 26, 28. A main condenser 100 is charged under the control of the thyristors 22, 26, and the thyristors 24, 28 are interrupted to stop charging at the overcharging time. The thyristors 22, 24, 26, 28 are controlled by a photocoupler which is formed of light emitting diodes 138, 140, 150, 152 and phototransistors 50, 64, 80, 92. |
