| 摘要 |
PURPOSE:To prevent previously an accident such as an electric shock at the maintenance time by providing a current detector of a power source for rescuing at the power interruption time. CONSTITUTION:If no-fuse breakers 1, 6 for a main power source and for rescuing in case of maintenance are interrupted, the outputs of an AC voltage detector 13 and a current detector 14 become H. Accordingly, an AND gate 16 becomes ON, a base circuit 12 operates, and a transistor 8 becomes ON. Thus, the stored charge of a smoothing condenser 3 is discharged through a resistor 7 and the transistor 8, and a DC line connected with a smoothing condenser 3 is set to zero potential. Consequently, an accident such as an electric shock due to the smoothing condenser can be previously prevented, and the maintenance work can be simplified. |
