This International Standard applies to capacitors for power electronics applications. The operating frequency of the systems in which these capacitors are used is usually up to 15kHz, while the pulse frequencies may be up to 5 to 10 times the operating frequency. The standard distinguishes between a.c. and d.c. capacitors which are considered as components when mounted in enclosures. This standard covers an extremely wide range of capacitor technologies for numerous applications, e.g. overvoltage protection, d.c. and a.c. filtering, switching circuits, d.c. energy storage, auxiliary inverters, etc. The following are excluded from this standard: – capacitors for induction heat-generating plants operating at frequencies between 40 Hz and 24 000 Hz (see IEC 60110-1 and IEC 60110-2); – capacitors for motor applications and the like (see IEC 60252-1 and IEC 60252 -2); – capacitors to be used in circuits for blocking one or more harmonics in power supply networks; – small a.c. capacitors as used for fluorescent and discharge lamps (see IEC 61048 and IEC 61049); – capacitors for suppression of radio interference (see IEC 60384-14); – shunt capacitors for a.c. power systems having a rated voltage above 1 000 V (see IEC 60871-1 and IEC 60871-2); – shunt power capacitors of the self-healing type for a.c. systems having a rated voltage up to and including 1 000 V (see IEC 60831-1 and IEC 60831-2); – shunt power capacitor of the non-self-healing type for a.c. systems having a rated voltage up to and including 1 000 V (see IEC 60931-1 and IEC 60931-2); – electronic capacitors not used in power circuits; – series capacitors for power systems (see IEC 60143); – coupling capacitors and capacitors dividers (see IEC 60358); – capacitors for microwave ovens (see IEC 61270-1); – capacitors for railway applications (see IEC 61881). Examples of applications are given in Clause 9.1.