| 摘要 |
PROBLEM TO BE SOLVED: To provide a three-phase full-wave rectifier having an open-phase detecting circuit capable of detecting an open-phase state in a primary side of a step-down transformer in a three-phase alternating current. SOLUTION: The three-phase full-wave rectifier is provided with a three-phase full-wave rectifier circuit for supplying alternating power obtained by full-wave- rectifying a three-phase alternating current input, a control circuit for controlling this, an open-phase detecting circuit for detecting the open-phase to provide a signal to the control circuit. The open-phase detecting circuit is provided with a three-phase bridge circuit 50 for full-wave-rectifying the three-phase alternating input, a voltage detecting circuit 80 for generating an energizing voltage when the voltage between output terminals of the circuit 50 is lower than the open-phase detecting voltage, a capacitor charging circuit 82 consisting of a resistor 40 having a charging time constant larger than a cycle of the three-phase alternating current and a capacitor 42 to charge the output of the circuit 50, and a photocoupler 44 for generating a signal indicating abnormality if the three-phase alternating current has an open-phase. COPYRIGHT: (C)2003,JPO
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