Secondary Side; Primary Side - ABB ACS800 User Manual

36

Secondary side

The following diagram represents the secondary side of a step-up system.
I
2
The impedance of the secondary side equals
The system is dimensioned using the nominal current of the motor:
Thus, the minimum voltage for the transformer secondary equals

Primary side

It can be assumed that the primary voltage of the transformer is about 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
• 0.85 × 400 V = 340 V (for 400 V drives)
• 0.87 × 500 V = 435 V (for 500 V drives)
• 0.9 × 690 V = 620 V (for 690 V drives).
Appendix – Step-up applications
R jX
c c
R
U / sqrt(3)
2
jX
2
( )
Z = R + R +
1 c m
I = I
2 n
⋅ ⋅
U = 3 I Z
2 2 1
m
U / sqrt(3)
n
m
2
( )
X + X
c m
equals
1