Rotor Cable Connection - ABB ACS800 Series Hardware Manual

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Rotor cable connection

Rotor cable connections for different cable types are represented below. For
minimum radio frequency interference (RFI) at the generator end, earth the cable
screen 360 degrees at the lead through or earth the cable by twisting the screen
(flattened width > 1/5 × length).
To effectively suppress radiated and conducted radio frequency emissions, the
shield conductivity must be at least 1/10 of the phase conductor conductivity.
The requirements are easily met with a copper or aluminium shield. The minimum
requirement of the motor cable shield of the converter is shown below. It consists of
a concentric layer of copper wires with an open helix of copper tape. The better and
tighter the shield, the lower the emission level and the bearing currents.
Insulation jacket
L1
L3
L2
Concentric Al/Cu shield
Converter
PE
U2 V2 W2
Site main
earth bus
PE
K
3 ~
Planning the electrical installation
Copper wire screen
Separate protective
conductor
Galvanised steel or
copper armour
Site main earth bus
L
M
G
Separate protective
conductor
A separate PE conductor system is used
only if local safety regulations do not
allow earthing of the converter and the
generator merely through the cable
screen. This solution increases bearing
currents compared to symmetrical
shielded cable, thus causing extra wear.
Helix of copper tape
L1
L2
L3
Converter
PE
U2 V2 W2
L
K M
PE
G
3 ~
Inner insulation
Cable core
Single core cable, shielded
or unshielded
Converter
PE
Site main
earth bus
PE
U2 V2 W2
L
K M
G
3 ~