| 摘要 |
PURPOSE:To obtain a firing pulse generating circuit with simple and stable operation by obtaining synchronizing pulses from one of three phase half wave circuits which are double star-connected, and creating the synchronizing pulses for the purpose of the other three phase half wave circuit from said synchronizing pulses. CONSTITUTION:Three phase AC is rectified by a control circuit with a double star interphase reactor constituted of three phase half wave control rectifier circuits 14a and 14b respectively including the output windings 141a, 141b of a main transformer 14 and an interphase reactor 5. In a DC arc welder which obtains DC electric power in the above-mentioned manner, the voltage of the in- phase as that of the winding 141a is generated in a transformer 10 for control. A locking pulse generating circuit 11 generates the pulses locked with the respective phase voltages of the transformer 10 and an intermediate pulse generating circuit 13 to be inputted with the outputs of the circuit 11 generate pulses at the intermediate phases of the respective input pulses. The circuits 14a, 14b are controlled by the phase control circuits 12a, 12b which are reset respectively by the outputs of the circuits 11, 13. |
