Siemens SINAMICS G130 Engineering Manual page 84

Fundamental Principles and System Description
Engineering Information
Optimized connection for high-frequencies between the converter and motor terminal box [2]
The connection between the converter and motor must always be made with a shielded, symmetrical, 3-wire, three-
phase cable.
Shielded cables with symmetrically arranged three-phase conductors L1, L2 and L3 and an integrated, 3-wire,
symmetrically arranged PE conductor, such as the PROTOFLEX EMV cable, type 2YSLCY-J supplied by Prysmian,
are ideal.
Shielded, symmetrically arranged three-phase cable with 3-core PE conductor
Alternatively, it is also possible to use a shielded cable containing only three-phase conductors L1, L2 and L3 in a
symmetrical arrangement. In this case, the PE conductor must be installed separately.
Symmetrical 3-wire three-phase cables with concentric copper or aluminum shield
Effective shield bonding is achieved if EMC cable glands are used to create a solid 360° contact between the shield
and motor terminal box and, at the other side in the converter cabinet, a solid 360° contact with the EMC shield
busbar using EMC shield clips. An alternative shield connection to the PE busbar in the converter using only long,
braided "pigtails" is less suitable, particularly if the pigtails are very long, as this type of shield bond represents a
relatively high impedance for high-frequency currents. Further additional shield bonds between the converter and
motor, e.g. in intermediate terminal boxes, must never be created as the shield will then become far less effective.
Motor terminal box
Shield bonding to motor terminal box using
an EMC gland
The cable symmetry combined with the concentric shield with good bonding connections at both sides ensures
effective high-frequency equipotential bonding between the converter and motor terminal box.
Where the cables used have a shield with poor high-frequency properties or the grounding systems are bad, it is
recommended to install a supplementary equipotential bonding conductor made of finely stranded, braided copper
wire with a large cross-section ( ≥ 95 mm
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© Siemens AG
EMC gland
Shield bonding to the EMC shield busbar in the converter
using an EMC shield clip
2
) between the PE busbar of the converter and the motor housing.