Reduced Run; Starting Reduced Run Operation - ABB ACS880-104 Hardware Manual

Reduced run

A "reduced run" function is available for inverter units consisting of parallel-connected
inverter modules. The function makes it possible to continue operation with limited current
even if one (or more) module is out of service, for example, because of maintenance work.
In principle, reduced run is possible with only one module, but the physical requirements of
operating the motor still apply; for example, the modules remaining in use must be able to
provide the motor with enough magnetizing current.
The wiring accessories needed during the procedure are available from ABB (see page
251).

Starting reduced run operation


WARNING! Repeat the steps described in section
precautions
Safety instructions for ACS880 multidrive cabinets and modules
(3AUA0000102301 [English]). Ignoring the instructions can cause
physical injury or death, or damage to the equipment.
1. If the inverter control unit is powered from the faulty module, connect the control unit to
another 24 V DC power supply. We strongly recommend using an external power
supply with inverter units consisting of parallel-connected modules.
2. Remove the module to be serviced from its bay.
3. If the STO (Safe torque off) function is in use, install the STO jumper wire set in place
of the missing module (unless the module was the last on the chain).
4. Install an air baffle to the top module guide to block the airflow through the empty
module bay.
5. In case the inverter unit has a DC switch with a charging circuit, disable the
appropriate channel on the charging monitoring unit.
6. Switch on the power to the inverter unit.
7. Enter the number of inverter modules present into parameter 95.13 Reduced run
mode.
8. Reset all faults and start the inverter unit. The maximum current is now automatically
limited according to the new inverter configuration. A mismatch between the number
of detected modules (95.14) and the value set in 95.13 will generate a fault.
9. If the STO function is in use, validate it as described in chapter
function (page 316).
on page 146. The complete safety instructions are given in
Maintenance 201
Electrical safety
The Safe torque off