Planning the electrical installation 39
Alternative power cable types
Power cable types that can be used with the drive are presented below.
Motor cable shield
To function as a protective conductor, the shield must have the same cross-sectional
area as the phase conductors when they are made of the same metal.
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 drive is shown below. It consists of a
concentric layer of copper wires. The better and tighter the shield, the lower the
emission level and bearing currents.
Symmetrical shielded cable: three phase
conductors, a concentric or otherwise
symmetrically constructed PE conductor
and a shield
Motor cables
(recommended for input cables also)
PE
conductor
and shield
Shield
Shield
PE
PE
Allowed as input cables
A four-conductor system: three phase
conductors and a protective conductor
Note: A separate PE conductor is required
if the conductivity of the cable shield is not
sufficient for the purpose.
Shield
PEPE
Insulation jacket Copper wire screen Cable core
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