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32 Guidelines for planning the electrical installation
Selecting the brake resistor
WARNING!
ABB is not responsible for user resistor selection or protection of the resistor.
Select the resistor according to the resistor specification given in the technical data.
In addition, consider the following:
•
Each output of the brake chopper module must feed a resistor of its own. There
are 3 outputs in the 3-phase brake chopper module.
•
The resistance ( R ) of the brake resistor must be equal to or above the value
specified. Never use resistance values below the specified value.
•
The brake resistor must withstand the specified brake cycles.
•
The ventilation of the space/room in which the brake resistor is located must
meet the air flow amounts specified.
•
The resistor must be equipped with a thermal switch (temperature sensor).
WARNING!
IEC 60664 and IEC 61800-5-1 require double or reinforced insulation between
resistor live parts and the temperature sensor. If the resistor assembly does
not fulfill the requirement, the temperature sensor must be isolated from the
I/O terminals, for example, with a suitable relay.
Selecting and routing the brake resistor cables
Resistor cable sizes and length
￭
See
Typical resistor cable
Minimizing electromagnetic interference
￭
Make sure that the installation is compliant with the EMC requirements. Obey these
rules in order to minimize electromagnetic interference caused by the rapid voltage
and current changes in the resistor cables:
•
Shield the brake resistor cable. Use shielded cable or a metallic enclosure. If you
use unshielded single-core cables, route them inside a cabinet that efficiently
suppresses the radiated emissions.
•
Install the cables away from other cable routes.
•
Avoid long parallel runs with other cables. The minimum parallel cabling separation
distance is 0.3 meters (1 ft).
•
Cross the other cables at 90° angles.
•
Keep the cable as short as possible in order to minimize the radiated emissions
and stress on the brake chopper. The longer the cable the greater the radiated
emissions, inductive load and voltage peaks over the IGBT semiconductors of the
brake chopper.
sizes.
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