Film Capacitors
Please let me know the service life of film capacitor.
The film capacitor will never wear out or fail if it is used within the rated voltage range having been normally set up.
However, this does not apply to the cases when the voltage exceeding the rated voltage is applied on it and when it is used in the high temperature/high humidity environment. In such cases, it is necessary to examine the details as to the propriety of its use and service life under respective conditions.
How much current can flow through the film capacitor?
Please refer to the allowable current data for frequency.
However, this data refers to the sine wave current. The waveform in the equipment in actual use frequently contains a considerably many high harmonic components. Even in slightly excess of the allowable values given in said data, self-heating of capacitor may fall below the allowable values in many cases. Finally, it is recommended to check and confirm the self-heating at the actual equipment.
Why the is derating of high frequency voltage necessary?
The high frequency voltage is to be limited by the allowable current value for high frequency as mentioned above. However, this voltage refers strictly to the AC components. In case when DC voltage is overlapped on it, the peak voltage should never exceed the DC rated voltage.
Moreover, in case of the waveforms different from the sine wave, it is also necessary to check and confirm whether the following conditions are satisfied.
(1) Current conditions are satisfied (less than the allowable current).
(2) In case when the pulse rated voltage is specified, Up-p voltage is lower than the rated voltage.