Capacitor Bank Unit (Cbu); Main Components In A Cbu Cabinet - ABB ACS6000 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.
Component
Liquid-cooled
DC-link capacitors
Charging unit
Discharging unit
Grounding switch
(1) Grounding switch
3BHS212794 E01 REV M
Table 3-3 Main components in a CBU cabinet
Description
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.
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.
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 "8.5 EXU control panel" on page 178.
1
Figure 3-9 CBU
ACS6000 USER MANUAL
03 POWER ELECTRONICS AND CABINET FEATURES
2
2
2
(2) DC-link capacitor
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