Placing The Brake Resistor; Protecting The System In Brake Circuit Fault Situations - ABB ACS560 Hardware Manual

144 Resistor braking
Follow these rules in order to minimize electromagnetic interference caused by the rapid
current changes in the resistor cables:
• 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 resistor

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 physical
contact.

Protecting the system in brake circuit fault situations

Protecting the system in cable and brake resistor short-circuitsituations
The input fuses will also protect the resistor cable when it is identical with the input cable.
Protecting the system against thermal overload
Equipping the drive with a main contactor is highly recommended for safety reasons. Wire
the contactor so that it opens in case the resistor overheats. This is essential for safety since
the drive will not otherwise be able to interrupt the main supply if the chopper remains
conductive in a fault situation. An example wiring diagram is shown below. We recommend
that you use resistors equipped with a thermal switch (1) inside the resistor assembly. The
switch indicates overtemperature and overload.
We recommend that you also wire the thermal switch to a digital input of the drive.