Frame R8I And Multiples; Dc Connection And Capacitor Charging - ABB ACS880-104 Hardware Manual

Frame R8i and multiples

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Frame R8i modules are used to achieve output powers from approximately 250 kW
upwards in single or parallel configurations. R8i modules run on wheels, and can easily be
removed from the cubicle for cable installation or service.
The motor connection is via a quick connector at the back of the module that couples
when the module is inserted into the cubicle. Each parallel-connected module is cabled
separately to the motor, or connected by busbars to adjacent modules to reduce the
number of cables. It is also possible to build an AC bus from each module to a separate
output cubicle.
As standard, the cooling fan is automatically speed-controlled according to the loading of
the inverter module. The fan is supplied internally. A direct-on-line fan is optionally
available by specifying option code +C188; for this option, the customer must connect an
external supply of 400 V 50/60 Hz to terminal block X50 (see page 37).
Internal du/dt filtering is optional for single-module 400/500 volt inverter units, but
mandatory with all 690 volt units and all parallel-connected modules.
Frame R8i to 6×R8i inverter units are controlled by a single BCU control unit installed
separately from the module(s). The control unit is connected to each inverter module by a
fiber optic link. The control unit can be powered from the inverter module (terminal block
X53), from an external 24 V DC supply, or both for redundancy. The control unit contains
the basic I/Os and slots for optional I/O modules. For descriptions of the I/O terminals on
the BCU control unit, see chapter
primarily installed on separate mounting plates.

DC connection and capacitor charging

The module must be equipped with external DC fuses. A DC switch/disconnector can be
installed if quick isolation of the module from the DC bus is required.
A capacitor charging circuit must be fitted if
•
the inverter module is connected to the DC bus through a DC switch/disconnector, or
•
the inverter unit is directly connected to the DC bus and the supply unit of the system
does not have a charging capability.
The charging circuit design presented in this manual consists of a charging switch,
resistors and a charging controller. When the inverter unit is connected to an energized
DC bus, the charging switch is closed first. When the charging is finished, the main DC
switch/disconnector can be closed and the charging switch opened. (The inverter unit will
not start if the charging switch is closed.)
Common mode filtering is implemented by running the DC bus through ferrite cores at the
input of the module.
The inverter control unit
Hardware description 35
(page 293). Other equipment is