ACS550-02/U2 User’s Manual 21
Planning the electrical installation
Emergency stop devices
For safety reasons, install the emergency stop devices at each operator control
station and at other operating stations where emergency stop may be needed.
Note: Pressing the stop key ( ) on the control panel of the drive does not
generate an emergency stop 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 section Ratings on
page 293 for the rated currents.
• The cable must be rated for at least 70
°C maximum permissible temperature of
conductor in continuous use. For US, see Additional US requirements on page
22.
• 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 covering the whole ACS550
range.
Symmetrical shielded cables must be used for the input and motor cables (see the
figure below). A four-conductor system 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 the stress on
motor insulation, bearing currents and wear.
The motor cable and its PE pigtail (twisted shield) should be kept as short as
possible in order to reduce electromagnetic emission (see details in section Power
cable connection diagram on page 36).
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
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
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