72
c.
Electromagnetic Compatibility (EMC)
Similar to all modern PWM variable speed drives, inverters use fast switching of high voltage and
currents to achieve high efficiency and reduced motor acoustic noise. This results in electromag-
netic interference (EMI) and radio frequency interference (RFI) that occurs at the switching fre-
quency and harmonics of this frequency.
For operational reasons the interference may need to be suppressed. As EMI and RFI can involve
very complex coupling modes, not all solutions can be easily found.
EC Directives
Inverters are able to comply with the EC Directives 89/336/EEC on limits to EMI and RFI with the
use of optional filters. Independent testing has demonstrated compliance to the following standards
when the optional filters are used.
EN 55011:
1991, Class A
pr EN 50082-2:
1992 (in part)
IEC 801-2:
1984
IEC 801-3:
1984
IEC 801-4:
1988
Filtering Selection for CC 204-222 Series
All CC series inverters use the same filter: N1F-2202. Physical dimensions, internal circuit layout
and component values are detailed below.
