| 摘要 |
PROBLEM TO BE SOLVED: To provide an inverter which is constituted, in such a way that the normal/abnormal state of its initial charging switching circuit can be discriminated surely and easily. SOLUTION: A timer is started when the charging of a smoothing capacitor is started (S1), and capacitor voltages V1 and V2 at points of time T1 and T2 before a magnet contactor MC is operated are acquired (S2 and S3). Then a capacitor voltage V4 at a time T4 after the contactor MC has operated is acquired (S4), and rates of voltage changes ΔVT12 and ΔVT24 are found from the voltages V1 , V2 , and V4 (S5 and S6). Thereafter, whether or not the difference between the ratios ΔVT12 and ΔVT24 exceeds a reference value is checked (S7), and when the difference exceeds the reference value, an inverting section is operated by deciding that the action of the contactor MC is normal. When the difference becomes equal to or lower than the reference value, a fault indication is made by deciding that the action of the contractor MC is abnormal. |
