Selecting And Routing The Brake Resistor Cables; Minimizing Electromagnetic Interference; Maximum Cable Length; Placing Custom Brake Resistors - ABB ACS880-104 Hardware Manual

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Selecting and routing the brake resistor cables

Use the same cable type for resistor as for inverter input cabling to ensure that the inverter
DC fuses also protect the resistor cable.

Minimizing electromagnetic interference

Follow 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 should be 0.3 meters (1 ft).
• 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 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 is 10 m (33 ft).
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Placing custom brake resistors

Install the resistors outside the drive in a place where they are able to cool effectively.
Arrange the cooling of the resistor in a way that
• no danger of overheating is caused to the resistor or nearby materials, and
• the temperature of the room the resistor is located in does not exceed the allowed
maximum.
Supply the resistor with cooling air or coolant according to the resistor manufacturer's
instructions.
WARNING!
The materials near the brake resistor must be non-flammable. The surface
temperature of the resistor is high. Air flowing from the resistor is of hundreds of
degrees Celsius. If the exhaust vents are connected to a ventilation system, make
sure that the material withstands high temperatures. Protect the resistor against
contact.
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Protecting the system against thermal overload

The inverter module protects itself and the resistor cable against thermal overload when
the cable is correctly dimensioned. The inverter control program includes a resistor and
resistor cable thermal protection function which can be tuned by the user. See the firmware
manual.
Equipping the drive system with a main contactor or breaker is highly recommended for
safety reasons. Wire the contactor or breaker so that it opens in case the resistor overheats.
Resistor braking using frames R1i...R4i inverter modules 331