where
Instantaneous load capacity of the custom resistor
P
R,
inst
Drive intermediate DC circuit voltage:
U
DC
1.35 · 1.2 · 415 V (when supply voltage is 380 … 415 V AC)
1.35 · 1.2 · 500 V (when supply voltage is 440 … 500 V AC) or
Resistance of the custom resistor
R
￭
Selecting and routing the brake resistor cables
Use the same cable type for the resistor cabling as for the drive input cabling to
ensure that the input fuses also protect the resistor cable. Alternatively, a two
conductor shielded cable with the same cross-sectional area can be used.
Minimizing electromagnetic interference
Obey these rules in order to minimize electromagnetic interference caused by the
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 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 degree 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 greater the radiated
emissions, inductive load and voltage peaks over the IGBT semiconductors of
the brake chopper.
Note: ABB has not verified that the EMC requirements are fulfilled with custom
brake resistors and cabling. The customer must consider the EMC compliance of
the complete installation.
Maximum cable length
The maximum cable length of the resistor cable(s) is 10 m(33 ft).
Resistor braking 245
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