| 摘要 |
PURPOSE:To effectively detect a malfunction even when the malfunction occurs in the main circuit element of an inverter by taking a deviation of output signals of inverters, and outputting a stop command to the inverter when the deviation signal is displaced out of the preset range. CONSTITUTION:In a protecting device of a multiplex inverter in which a plurality of inverters 1, 2 are connected, the output currents of the inverters 1, 2 are detected by current transformers 3A, 3B, a deviation signal of the voltage signals corresponding to the detected currents is produced by a matching circuit 5, input to a window comparator 6 to compare with set voltages V0-V0 by matching units 61A, 61B. If the thyristor 21 of the inverter 2, for example, remains nonconductive, a stop command is generated from an OR circuit 8 to the inverters 1, 2. If the output current of one inverter 1, for example, becomes excess, the deviation signal (V1-V2) exceeds the set voltage V0 or -V0. Accordingly, a stop command is generated from the OR circuit 8 to the inverters 1, 2. |
