Selecting The Power Cables; General Rules - ABB ACS880-37 Hardware Manual

Selecting the power cables

General rules


Select the input power and motor cables according to local regulations:
•
Select a cable capable of carrying the drive nominal current. See section
(page 179) for the rated currents, and section
•
Select a cable rated for at least 70 °C maximum permissible temperature of conductor
in continuous use. For US, see
•
The inductance and impedance of the PE conductor/cable (grounding wire) must be
rated according to permissible touch voltage appearing under fault conditions (so that
the fault point voltage will not rise excessively when a ground fault occurs).
•
600 V AC cable is accepted for up to 500 V AC. 750 V AC cable is accepted for up to
600 V AC. For 690 V AC rated equipment, the rated voltage between the conductors
of the cable should be at least 1 kV.
Use symmetrical shielded motor cable (see page 84). Ground motor cable shields 360° at
both ends. Keep the motor cable and its PE pigtail (twisted shield) as short as possible to
reduce high-frequency electromagnetic emissions.
Note: When continuous metal conduit is employed, shielded cable is not required. The
conduit must have bonding at both ends.
A four-conductor system is allowed for input cabling with restrictions, but shielded
symmetrical cable is recommended (see page 84).
Compared to a four-conductor system, the use of symmetrical shielded cable reduces
electromagnetic emission of the whole drive system as well as the stress on motor
insulation, bearing currents and wear.
The protective conductor must always have an adequate conductivity. The table below
shows the minimum cross-sectional area related to the phase conductor size according to
IEC 61800-5-1 when the phase conductor and the protective conductor are made of the
same metal.
Cross-sectional area of the phase conductors
S (mm
16 < S < 35
35 < S < 400
Additional US
2
)
S < 16
Guidelines for planning the electrical installation 81
Typical cable sizes
requirements, page 85.
Minimum cross-sectional area of the
corresponding protective conductor
Ratings
(page 82).
2
S (mm )
p
S
16
S/2