| 摘要 |
PURPOSE:To previously check the connecting state of a bypath line by detecting the line voltage between respective bypath lines on the power supply side and load side and then detecting predetermined current flowing through the bypath lines in the insulated wires using current transformers on the load side. CONSTITUTION:An erroneous connection detecting circuit 4 detects line voltages V12S, V32S, V12L, V32L, V1SL, V2SL, and V3SL between bypath lines B1S and B2S, B3S and B2S, B1L and B2L, B3L, and B2L, B1S and B1L, B2S and B2S, and B3S, and B3L on the power supply S side and the load L side. A current detecting circuit 5 detects a predetermined current flowing through the bypath lines B1S-B3S and B1L-B3L into insulated wires A1S-A3S, A1L-A3L using current transformers CT1-CT3 on the load L side. Based on a detection output from the circuit 4 or 5, a control circuit 6, e.g. a CPU, switches relay contacts P1-P3 connecting the bypath lines B1S-B3S, and B1L-B3L with the power supply S side and the load L side. |
