| 摘要 |
PURPOSE:To prevent tripping of an AC machine by deciding abnormality of the main circuit and the current detector for the AC machine based on a test command fed from a test control means and a value detected through the current detector, and detecting the abnormality in advance. CONSTITUTION:Voltages are applied, in three modes, onto a main circuit then current detection signals DW, DU, DV to be fed from current detectors 4, 5, 6 upon application of voltage are examined. In other words, 1. Voltage is applied between phases U-V and phase W is gate blocked, 2. Voltage is applied between phases V-W and phase U is gate blocked, or 3. Voltage is applied between phases W-U and phase V is gate blocked. According to this test, an operator can search the cause of the displayed abnormality without starting operation of an AC machine 3 when any one abnormality is detected and displayed. |
