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46 Guidelines for planning the electrical installation
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The resistance (R) of the brake resistor assembly must be equal to or above the value
specified. Never use resistance values below the specified value.
•
The resistor must withstand the specified brake cycles.
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The ventilation of the space/room in which the resistors are located must meet the air
flow amounts specified.
•
The resistor assembly must be equipped with a thermal switch.
WARNING!
IEC 60664 and IEC 61800-5-1 require double or reinforced insulation between
resistor live parts and the sensor. If the resistor assembly does not fulfill the
requirement, the I/O terminals on the control unit must be protected against contact
and must not be connected to other equipment, or the temperature sensor must
be isolated from the I/O terminals, for example, with a suitable relay.
Selecting and routing the brake resistor cables
￭
Typical resistor cable sizes
See the technical data.
￭
Minimizing electromagnetic interference
Obey these rules in order to minimize the electromagnetic interference caused by rapid
current changes in the resistor cables:
•
Shield the braking power line completely, either by using shielded cable or a metallic
enclosure. Unshielded single-core cable can only be used if it is routed inside a cabinet
that efficiently suppresses 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).
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Cross the other cables at right angles.
•
Keep the cable as short as possible in order to minimize the radiated emissions and
stress on chopper IGBTs. The longer the cable, the higher the radiated emissions,
inductive load and voltage peaks over the IGBT semiconductors of the brake chopper.
￭
Maximum cable length
See the technical data.
￭
EMC compliance of the complete installation
Note: ABB has not verified that the EMC requirements are fulfilled with external user-defined
brake resistors and cabling. The EMC compliance of the complete installation must be
considered by the customer.
Placing the brake resistors
Install the resistors outside the drive in a place where they will cool.
Arrange the cooling of the resistor in a way that:
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no danger of overheating is caused to the resistor or nearby materials
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