ABB ACS880 ESP, Firmware Manual

Page: 489 / 494

Appendix: ESP with step-up transformer and sine filter 489
Primary side:
The primary voltage can be assumed to be 10% lower than the supply voltage of the
drive because of the voltage drop in the sine filter and the drive.
The primary voltage U 1 is
• 0.85 X 400 V = 340 V (for 400 V drives)
• 0.87 X 500 V = 435 V (for 500 V drives)
• 0.9 X 690 V = 620 V (for 690 V drives)
Secondary side:
The following diagram represents the secondary side of a step-up system.
The impedance of the secondary side is
The system is dimensioned using the nominal current of the motor:
The minimum voltage for the transformer secondary is
I
2
R
c
jX
c
R
m
jX
m
U
n
/sqrt(3)
U
n
/sqrt(3)
Z
1
R
C
R
m
+
( )
2
X
C
X
m
+
( )
2
+ =
I
2
I
n
=
U
2
3 I
2
Z
1
⋅ ⋅
=