ABB ACS850 series, Hardware Manual

Page: 44 / 120

Planning the electrical installation
44
Alternative power cable types
Power cable types that can be used with the drive are represented below.
Motor cable shield
To function as a protective conductor, the shield must have the same cross-sectional
area as a phase conductor 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 with an open helix of copper tape. The better and
tighter the shield, the lower the emission level and the bearing currents.
Protecting the relay output contacts and attenuating disturbances in case
of inductive loads
Inductive loads (relays, contactors, motors) cause voltage transients when switched
off.
The relay outputs on the drive are protected with varistors (250 V) against
overvoltage peaks. In addition, it is highly recommended to equip inductive loads
Symmetrical shielded cable: three phase conductors and
a concentric or otherwise symmetrically constructed PE
conductor, and a shield
Motor cable
(also recommended for supply cabling)
PE conductor
and shield
Shield
Shield
Note: A separate PE conductor is required if the
conductivity of the cable shield is not sufficient for the
purpose. See section
General rules above.
A four-conductor system: three phase conductors and
a protective conductor.
Shield
PE
PE
Allowed for supply cabling
PE PE
Insulation jacket
Copper wire screen
Helix of copper tape
Cable core
Inner insulation