| 摘要 |
PURPOSE:To reduce by half electric power which is required for an arc pulse circuit while securing the reliability of firing by dividing by 4 the energizing time of a controlled rectifier, and outputting the firing signal of the prescribed pulse train during the initial and third period. CONSTITUTION:Energizing period instruction signals 33U-33Z of controlled rectifiers are applied as input signals. A pulse signal is formed at the rising time point of the respective energizing period instructing signals 33U-33Z by monostable multivibrator 5-10. After these pulse signals are gathered as energizing start pulse signal 11a by an OR gate 11, they are inputted to monostable multivibrator 12, and a firing pulse train output period signal 12a is formed. The pulse trains 13a from the signal 11a and monostable multivibrator 13 are applied to OR gate 14, which produces logical sum, thereby forming a firing pulse train signal 14a. The signal 14a, signals 33U-33Z and the signal 12a are inputted to AND gates 15-20, thereby forming a firing pulse. |
