Planning the electrical installation 55
Alternative power cable types
Power cable types that can be used with the drive are represented below.
The following power cable type is not allowed.
Motor cable shield
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 aluminum shield. The minimum
requirement of the motor cable shield of the drive is shown below. It consists of a
concentric layer of copper wires with an open helix of copper tape or copper wire.
The better and tighter the shield, the lower the emission level and bearing currents.
Symmetrical shielded cable with individual shields for each phase conductor
is not allowed on any cable size for input and motor cabling.
Symmetrical shielded cable: three phase
conductors and a concentric or otherwise
symmetrically constructed PE conductor, and a
shield
Recommended
PE conductor
and shield
Shield
Shield
A separate PE conductor is required if the
conductivity of the cable shield is < 50%
of the conductivity of the phase
conductor.
A four-conductor
system: three phase
conductors and a
protective conductor
Shield
PE
PE
PE
Not allowed for motor cables with
phase conductor cross section larger
than 10 mm
2
[motors > 30 kW (40 hp)].
Not allowed for motor cables
Insulation jacket
Copper wire screen
Helix of copper
tape or copper wire
Cable core
Inner insulation
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