ABB ACA 6 Series, Hardware Manual

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Chapter 3 – Electrical Installation
ACA 6xx Sections and ACS/ACC 6x7 (132 to 3000 kW) Frequency Converters 3-3
Alternatives Power cable types that can be used with ACx 600 are represented
below.
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 effectiveness of the shield can be
evaluated e.g. on the basis of the shield inductance, which must be low
and only slightly dependent on the frequency. These requirements are
easily met with a copper or aluminium shield/armour. The minimum
requirement of the motor cable shield of the ACx 600 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.
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.
Not allowed for motor cable.
Shield
PE
PE
PE
Insulation jacket
Copper wire screen
Helix of copper tape
Cable core
Inner insulation