| 摘要 |
PROBLEM TO BE SOLVED: To exactly determine the life of a capacitor for smoothing for a DC power source circuit provided inside, and to exactly operate predicted maintenance for the life of the DC power source circuit. SOLUTION: An aluminum electrolytic capacitor 20, having a life equivalent to the life of an aluminum electrolytic capacitor in a DC power source circuit 12, is selected. A measuring circuit 19 measures the electrostatic capacity of the aluminum electrolytic capacitor 20 and applies it to a logical arithmetic circuit 13. The logical arithmetic circuit 13 stores the measured data of the measuring circuit 19 at the time of power supply in a non volatile memory 21 as initial data indicating the initial electrostatic capacity of the capacitor 20, and compares the initial electrostatic capacity with a lapse electrostatic capacity indicated by the measured data of the measuring circuit 19, each time a previously set measuring cycle time passes, and generates a warning signal when the latest lapse electrostatic capacity loweres more than previously set ratios with respect to the initial electrostatic capacity. |
