Hardware Manual

Table Of Contents
Resistor braking 245
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.
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
The maximum length of the resistor cable(s) is 10 m (33 ft).
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:
no danger of overheating is caused to the resistor or nearby materials
the temperature of the room the resistor is located in does not exceed the allowed
maximum.
Supply the resistor with cooling air/water 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, ensure that the material withstands high temperatures. Protect the resistor
against contact.