| 摘要 |
PURPOSE:To maintain safety, by providing a common capacitor and adopting a dual system. CONSTITUTION:A generation rate, at which the voltage of a power supply 1 is applied to a case 3, is denoted as P. When a failure rate lambda, at which a common capacitor 5 fails in short circuit mode, is 1 (FIT), a failure rate lambdat, at which a capacitor C1 and the common capacitor 5 fail simultaneously in short circuit mode, comes into lambdat 2Xlambda1XlambdaXt, where t denotes an operating time. When the operating time t is 10 years, i.e., about 10<5> hour, P comes into P=1/10X1/10X2X1/10<9>X1/10<9>X10<5>=2X10<-15> (FIT). Therefore, even if the capacitor C1, C2 for absorbing noises fail in short circuit mode, unless the added common capacitor 5 fails simultaneously in short circuit mode, it is not caused that the voltage of the power supply 1 is applied to the case 3. Thereby, safety can be maintained. |
