03 POWER ELECTRONICS AND CABINET FEATURES
3BHS842007 E01 REV C
ACS6080
USER MANUAL
3.2.3
Capacitor bank unit (CBU)
The capacitor bank unit (CBU) smooths the DC-link voltage and decouples
the rectifier from the inverter. A CBU consists of DC-link capacitors, a
charging unit and a grounding switch.
The width of the unit (800 mm or 1000 mm) depends of the number of
capacitors that are required.
The CBU is based on a modular design and the amount of DC-link
capacitors in the CBU depends on the converter power rating.
Figure 3-9 CBU
Table 3-3 Main components in a CBU cabinet
Component
Description
Liquid-cooled
DC-link capacitors
Charging unit
To avoid excessive inrush currents after the main circuit
breaker has been closed, the capacitors are charged
before the drive is connected to the main power source.
Discharging unit
This optional unit discharges the DC-link capacitors if the
drive is not equipped with a voltage limiter unit, resistor
braking unit or braking chopper unit.
Grounding switch
The grounding switch is a safety switch to ground the DC
bus of the drive. These can only be closed if the DC-link
capacitors have been discharged. For more information,
see “8.6 EXU control panel” on page 168.
(1) Grounding switch
(2) DC-link capacitor
1
2
2
2
