03 POWER ELECTRONICS AND CABINET FEATURES
3BHS842007 E01 REV C
ACS6080
USER MANUAL
3.3.4
Braking units
A braking chopper unit (BCU) and a resistor braking unit (RBU) are
available for the ACS6080.
These braking units are used for applications that require fast braking
where regenerative braking is not allowed, eg, marine applications;
therefore these units are typically part of a drive that contains an LSU. The
BCU and RBU enable such drives to perform effective motor braking.
However, BCUs and RBUs can also be used in combination with ARUs, eg,
mine hoists and other special applications that require emergency
braking in the event of a power outage.
During braking, the BCU limits the DC-link voltage and converts the
braking energy into heat that is dissipated in resistors. IGCT
semiconductors switch the braking energy to the resistors.
Table 3-5 BCU braking power
Braking resistor (ohm)
Single braking power
(kW)
Double braking power
(kW)
RBU
800
1600
10
1100
2200
8
1400
2800
7
1600
2800
6
1900
3200
5
2200
3700
4
2800
4500
3.6
3100
5600
Table 3-6 RBU braking power
Single braking power (kW)
Double braking power (kW)
800
1600
