Excitation Unit (Exu) - ABB ACS6080 User Manual

3.3.5

Excitation unit (EXU)

The EXU supplies a synchronous motor with excitation power. The EXU is
available for the following excitation methods:
• Brush excitation (DC excitation): Uses a DCS880 AC-to-DC converter
which is supplied by the mains. The converter controls the direct
current for generating the magnetic field. Brushes and slip-rings
feed the DC current to the rotor.
• Brushless excitation (AC excitation): Uses a three-phase DCT880 AC-
power controller. The power controller feeds an exciter which is
mounted on the shaft of the main motor. The rotating armature of
the exciter supplies a rectifier which generates the DC current for
producing the magnetic field in the synchronous motor.
Note: For more information, see the "Air-cooled excitation units, brush
brushless excitation technical data" (project-specific).
A A
1 1
2 2
2
Figure 3-26 EXU H4/T4 frame cabinet (A) and EXU H6 frame cabinet (B)
(1) Ground fault detection
device (optional)
(2) Fuses
(3) Control compartment
(4) Fan units
3BHS842007 E01 REV C
03 POWER ELECTRONICS AND CABINET FEATURES
3 3
4
7
5
6
(5) DCS880/DCT880 H4 unit
(6) Overvoltage protection (not
shown in A)
(7) DCS880 H6 unit
ACS6080 USER MANUAL
B B
1
6
4
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