ABB PQFM - Page 51

Manual Power Quality Filter PQFM  Electrical design and installation 51
an appropriate protection mechanism that protects both the feeding cable and the filter
unit. As a protection mechanism it is recommended to use fuses of type gG/gL with the
RMS current ratings given in Table 20.
Table 20: RMS current ratings for protection fuses
Filter nominal current rating
(Arms)
Minimum fuse protection
(Arms)
Maximum fuse protection
(Arms)
70
90
160
100
130
160
130
160
200
150
200
200
Voltage rating and short circuit current handling capability should be in accordance with
the network characteristics.
As an alternative to fuse protection, MCCB protection of appropriate sizing can also be
used. When the customer protection is in place, the following PQFM input protection
will result.
L1
L2
L3
To PQFM
power stage
To PQFM
control circuit
To surge arrester
(optional)
2.5mm² reinforced
6A (10X38 for up to 480V)
Customer added protection
PQFM filter unit
Figure 29: Symbolic representation of the PQFM input protection (CE version)
In case the optional internal fuse protection is installed, the internal fuses have the
following characteristics: