Siemens Simovert Masterdrives Compendium page 99

Instructions for Design of Drives in Conformance with EMC Regulations
3.4.2 Use of filters and coupling elements
Radio interference
suppression filters
dv/dt filters
Sinusoidal filters
Coupling elements
3-12
♦ Minimum clearance 20 cm.
♦ De-coupling by means of grounded partitions is even better. It is not
permissible to route cables which have been assigned to various
zones together in the same cable ducts!
♦ If necessary, filters should be installed at the interface locations
between the zones.
♦ Non-shielded signal cables can be used within one zone.
♦ All bus cables (e.g. RS 485, RS 232) and signal cables leaving the
cabinet must be shielded.
EMC cannot be brought about just by installing filters! Measures such
as shielded motor feeder cables and spatial separation are also
necessary.
Radio interference suppression filters reduce the cable-related noise
interference voltage at the mains connection point. In order to maintain
the limit values ("First environment" or "Second environment"), a radio
interference suppression filter is necessary, irrespective of whether a
dv/dt or sinusoidal filter is used at the output of the frequency converter.
dv/dt filters are used in the first place to protect the motor winding, by
reducing the maximum voltage stressing, and in the second place, the
reduced voltage gradient will result in a lower noise current.
Sinusoidal filters are low-pass filters which generate an almost
sinusoidal voltage from the voltage blocks which the converter switches
at the output terminals. The voltage gradient and the maximum voltage
peaks are limited even more effectively than in the case of dv/dt filters.
In addition, data line filters and/or coupling elements may be required at
the interfaces between the zones. Coupling elements with electrical
isolation (e.g. isolating amplifiers) prevent the noise from being
propagated from one zone to the next. Isolating amplifiers particularly
have to be provided in the case of analog signals.
6SE7087-6QX70 (Version AD)
Compendium Motion Control
05.2003
Siemens AG
SIMOVERT MASTERDRIVES