Definitions
P
BRmax
The maximum braking capacity of the drive, when the length of the braking
pulse is at most 1 minute for each 10 minutes (P
BRcont
× 1.5). Must be
more than the desired braking power.
P
BRcont
The continuous braking capacity of the drive
R
max
The maximum resistance value of the brake resistor that can provide
P
BRcont
R
min
The minimum permitted resistance value of the brake resistor
Selecting and routing the brake resistor cables
Use a shielded cable specified in the technical data.
￭ 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 length of the resistor cable(s) is 10 m (33 ft).
Placing the 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.
176 Resistor braking
To Next Page
Loading...
