| 摘要 |
PURPOSE:To prevent a rectifier from operating in the defective phase by generating one phase control pulse between zero phase of a delay voltage to a power source and the zero phase of a leading voltage led at 90 deg. from the delay voltage. CONSTITUTION:Interphase voltages of the respective phases are produced drom a delta-connection detecting transformer 31, led to phase converters 32A-32C for the respective voltages, thereby obtaining 90 deg. leading voltage. The 90 deg. leading voltage and the interphase voltage are supplied to AND elements 35A-35C and NOR elements 36A-36C, inputted to the first and second sawtooth wave generators 38-1, 38-2, the outputs are compared with a phase control signal by the first and second comparators 39-1, 39-2. The pulse synchronized with the output is obtained to generate phase control pulses G1-G6. |
