Siemens SIMOVERT MV Series Commissioning Instructions page 16

For analog signal cables, with low signal levels (mV. µA), the cable screen is
connected at one end in the cabinet, to the screen rail (this avoids ground/earth
loops and line-frequency noise which is coupled-in). The open screen end can be
connected with the housing through a noise suppression capacitor e.g. 0.1 µF
100 V MKT).
♦ All of the signal cables must be screened. Separate the signal cables according
to signal groups.
Unscreened cables carrying digital signals must never be routed next to cables
carrying analog signals. If you which to use a common signal cable, then the
individual signals must be mutually screened.
♦ Route cables as close as possible to grounded sheet metal surfaces. This
reduces the influence of noise.
♦ Avoid unnecessary long cables. Long cable lengths generate additional
capacitances and inductances where noise can be coupled-in.
♦ A minimum clearance of > 20 cm must be maintained between signal cables
and power cables below 500 V AC; a clearance of > 30 cm must be maintained
to power cables at over 1 kV AC.
♦ Crossovers with power cables should, if possible, be made at an angle of 90°.
If the grounding situation is not completely known, it probably makes sense to
connect a potential bonding conductor in parallel with each power cable.
Recommended cross-section, 50 mm
It is not permissible to use undampened contactors in the drive converter cabinets.
Thus, all of the contactors mounted in the factor have RC circuitry. If undampened
contactors are used in an adjacent cabinet, then sheet steel barriers must be
installed between the cabinets.
Contactor coils, which are connected to the same supply as the auxiliary power
supply of the drive converter, or are located close to the converter, must have
overvoltage limiting circuitry (e.g. RC elements, varistors).
Additional wiring in the cabinet should be kept as short as possible and should be
routed as close as possible to the cabinet housing or the mounting panels.
Unscreened cables of the same circuit (incoming and outgoing conductor) must be
twisted.
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Siemens AG
SIMOVERT MV
6SE8004-0BH76
Commissioning Instructions