| 摘要 |
PURPOSE:To display and record a leak current and, at the same time, to alarm and cut off the occurrence of the leak by detecting the leak current by means of a protective display outputting unit provided with a zero-phase current transformer. CONSTITUTION:When a leak current flows to an electric circuit 1, voltages are respectively induced across each secondary coil 2a and 2b of a zero-phase current transformer 2 and the voltage induced across the coil 2a is impressed on output circuits 4 and 12 through amplifiers 3 and 11. When the leak current exceeds a prescribed value, a relay 5 is actuated by the output of the circuit 4 and a contact 5a is switched, resulting in actuation of a buzzer. When the leak current further exceeds a further larger prescribed value, a relay 13 is actuated by the output of the circuit 12 and a contact 13a is switched. As a result, a breaker is actuated and the circuit 1 is cut off. The voltage induced across the coil 2b is impressed on a digital display 26 through amplifiers 21 and 22 and a changeover switch 25 and the magnitude of the leak current is displayed. The output of the coil 2b is outputted as analog data through an amplifier 23, changeover switch 29 and selection output circuit 27 and the maximum value of leak currents of plural circuits can be recorded. |
