Siemens SIMOVERT MASTERDRIVES Manual page 57

05.2003
3.5 Design of drives in conformance with EMC regulations
3.5.1 Basic EMC rules
Rule 1
NOTE
Rule 2
Rule 3
Rule 4
Rule 5
Rule 6
Rule 7
Rule 8
Siemens AG 6SE7087-6QX70 (Version AD)
SIMOVERT MASTERDRIVES
Instructions for Design of Drives in Conformance with EMC Regulations
Rules 1 to 13 are generally applicable. Rules 14 to 20 are particularly
important for limiting noise emission.
All of the metal cabinet parts must be connected through the largest
possible surface areas (not paint on paint). If required, use serrated
washers. The cabinet door must be connected to the cabinet through
grounding straps which must be kept as short as possible.
Grounding installations/machines is essentially a protective measure.
However, in the case of drive systems, this also has an influence on the
noise emission and noise immunity. A system can either be grounded
in a star configuration or each component grounded separately.
Preference should be given to the latter grounding system in the case
of drive systems, i.e. all parts of the installation to be grounded are
connected through their surface or in a mesh pattern.
Signal cables and power cables must be routed separately (to eliminate
coupled-in noise). Minimum clearance: 20 cm. Provide partitions
between power cables and signal cables. The partitions must be
grounded at several points along their length.
Contactors, relays, solenoid valves, electromechanical operating hours
counters, etc. in the cabinet must be provided with quenching elements,
for example, RC elements, diodes, varistors. These quenching devices
must be connected directly at the coil.
Non-shielded cables associated with the same circuit (outgoing and
incoming conductor) must be twisted, or the surface between the
outgoing and incoming conductors kept as small as possible in order to
prevent unnecessary coupling effects.
Eliminate any unnecessary cable lengths to keep coupling
capacitances and inductances low.
Connect the reserve cables/conductors to ground at both ends to
achieve an additional shielding effect.
In general, it is possible to reduce the noise being coupled-in by routing
cables close to grounded cabinet panels. Therefore, wiring should be
routed as close as possible to the cabinet housing and the mounting
panels and not freely through the cabinet. The same applies for reserve
cables/conductors.
Tachometers, encoders or resolvers must be connected through a
shielded cable. The shield must be connected to the tachometer,
encoder or resolver and at the SIMOVERT MASTERDRIVES through a
large surface area. The shield must not be interrupted, e.g. using
intermediate terminals. Pre-assembled cables with multiple shields
should be used for encoders and resolvers (see Catalog DA65.11).
Compendium Motion Control
3-13