This standard applies to capacitors for power electronics intended to be used on rolling stock. The rated voltage of capacitors covered by this part is limited to 10 000 V. The operating frequency of the systems in which these capacitors are used is usually below 2500 Hz, while the pulse frequencies may go up to several thousand hertz in some cases beyond 10 000 Hz. It distinguishes between a.c. and d.c. capacitors. They are considered as components mounted in enclosures.