ABB ACS550-02 User Manual page 12

10
WARNING! Circuit breakers are not capable of providing sufficient protection
because they are inherently slower than fuses. Always use fuses with circuit
breakers, if you are not sure of the circuit breaker braking capacity and mains short
circuit power.
Ground Fault Protection
The drive is equipped with an internal ground fault protective function to protect the
unit against ground faults in the motor and the motor cable. This is not a personal
safety or a fire protection feature. The ground fault protective function can be
disabled with a parameter contact ABB for more information.
The EMC filter of the drive includes capacitors connected between the main circuit
and the frame. These capacitors and long motor cables increase the ground leakage
current and may cause fault current circuit breakers to function.
Emergency Off Devices
For safety reasons, install the emergency off devices at each operator control station
and at other operating stations where emergency off may be needed. Pressing the
stop key (
of the motor or separate the drive from dangerous potential.
Selecting the Power Cables
General Rules
Dimension the mains (input power) and motor cables according to local
regulations:
• The cable must be able to carry the drive load current. See chapter
Data
• The cable must be rated for at least 70
temperature of conductor in continuous use. For US, follow local codes for cable
size .
• 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 an ground fault
occurs).
• 600 VAC cable is accepted for up to 500 VAC concerning the whole ACS550
range.
For frame sizes R7 and R8, symmetrical shielded motor cable must be used (figure
below). A four-conductor system used up to 30 kW motors cannot be used.
Compared to a four-conductor system, the use of symmetrical shielded cable
reduces electromagnetic emission of the whole drive system as well as motor
bearing currents and wear of bearings.
Installation
) on the control panel of the drive does not generate an emergency off
for the rated currents.
° °
C (158 F) maximum permissible
Technical