ABB REC670 Applications Manual page 222

Section 8
Current protection
216
Capacitor Unit
(Can)
IEC09000753 V1 EN-US
Figure 92: Replacement of a faulty capacitor unit within SCB
There are four types of the capacitor unit fusing designs which are used for
construction of SCBs:
Externally where an individual fuse, externally mounted, protects each capacitor unit.
fused
Internally where each capacitor element is fused inside the capacitor unit
fused
Fuseless where SCB is built from series connections of the individual capacitor units (that is,
strings) and without any fuses
Unfused where, in contrary to the fuseless configuration, a series or parallel connection of
the capacitor units is used to form SCB, still without any fuses
Which type of fusing is used may depend on can manufacturer or utility preference
and previous experience.
1MRK 511 401-UEN A
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IEC09000753_1_en.vsd
Bay control REC670 2.2 IEC
Application manual