| 摘要 |
PROBLEM TO BE SOLVED: To provide an electricity source and a method for determining useful life of a capacitor allowing the useful life of the capacitor for smoothing a direct current to be accurately determined. SOLUTION: A smoothing capacitor 3 is charged at the time when an electricity source voltage is 0V to find a peak valueΔV of charging current for the smoothing capacitor 3 just after the start of the charging and peak current reaching timeΔt taken for reaching the peak valueΔV. The found peak valueΔV is compared with a useful-life determination reference value Vref, and further, the peak current reaching timeΔt is compared with a determination reference time Tref. In this comparison, it is determined that the smoothing capacitor 3 is at the end of its service life, if the peak valueΔV is not more than the determination reference value Vref and the peak current reaching timeΔt is not more than the determination reference time Tref. COPYRIGHT: (C)2011,JPO&INPIT |
