ABB FOCH, Hardware Manual, Page: 15 / 38

The total continuous rms current of the motors is
I
th
=
I
th1
+
I
th2
+
I
th3
= 463 A.
The supply voltage (
U
N
) is 660 V. Thus, the average intermediate circuit DC voltage of
the drive is
U
dc
= 1.35 × U
N
= 1.35 × 660 V = 891 V.
The additional energy loss in the d u/dt filter is
E = ½ · C · (U
dc
)
2
= ½ × 463 nF × (891 V)
2
= 184 mJ.
When 463 A and 184 mJ are compared to the values of Maximum values table, it can
be seen that a filter of type FOCH0610-70 can be used.
Selecting the d u/dt filter 15