| 摘要 |
PURPOSE:To easily detect a first cause of abnormality only by combining high- speed switching operations of reverse blocking triode thyristors and operations of electromagnetic relays. CONSTITUTION:When, for example, a contact 5-1 is closed due to the abnormality of a facility, a gate current i1 is made to flow to the gate of a reverse blocking triode thyristor 1-1 and the thyristor 1-1 is turned on. As a result, a coil 2-1 is energized and contacts 2a-1 and 2b-1 are closed. Simultaneously, an electric current i2 is made to flow to the inverter circuit 4-1 of an IC and the state of the output signal of the circuit 4-1 is inverted and, accordingly, the state of the output signal of the IC is inverted. As a result, the gate current i1 is cut off and other thyristors 1-(n-1) and 1-n cannot be turned on even when the contacts t-(n-1) and 5-n are closed. On the other hand, the first operated electromagnetic relay self-holds, since the contact 2a-1 is closed, and the contact 2b-1 is maintained in the closed state and occurrence of an abnormal state can be alarmed continuously. Therefore, the first abnormality can be specified easily. |
