Guidelines for planning the electrical installation 77
Alternative power cable types
The recommended and not allowed power cable types to be used with the drive are
presented below.
Recommended power cable types
Power cable types for limited use
Not allowed power cable types
Motor cable shield
If the motor cable shield is used as the sole protective earth conductor of the motor, make
sure that the conductivity of the shield is sufficient. See subsection General rules on page
75, or IEC 61800-5-1. To effectively suppress radiated and conducted radio-frequency
emissions, the cable 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 three phase conductors and a concentric PE
conductor as shield. The shield must meet the requirements of IEC 61800-5-1,
see page 75. Check with local / state / country electrical codes for allowance.
Symmetrical shielded cable with three phase conductors and a concentric PE
conductor as shield. A separate PE conductor is required if the shield does not
meet the requirements of IEC 61800-5-1, see page 75.
Symmetrical shielded cable with three phase conductors and symmetrically
constructed PE conductor, and a shield. The PE conductor must meet the
requirements of IEC 61800-5-1.
A four-conductor system consisting of unshielded single-core phase conductors
and a protective conductor on a cable tray) is not allowed for input cabling on
IT (ungrounded) networks.
WARNING! Do not use unshielded single-core cables with drives on IT
(ungrounded) networks. A dangerous voltage can become present on
the non-conductive outer sheath of the cable. This can cause injury or
death.
A four-conductor system consisting of separate phase conductors (regardless of
the presence of shielding) and a protective conductor on a cable tray is not
allowed for motor cabling.
Symmetrical shielded cable with individual shields for each phase conductor is
not allowed on any cable size for input and motor cabling.
To Next Page
Loading...
