Example; Motor; Cable; Secondary Side - ABB ACS800 User Manual

Example

The nominal voltage of the drive in this calculation is 690 V.

Motor

U = 3300 V
n
I = 106 A
n
f = 50 Hz
n
( ϕ )
cos = 0,82
n
------------------- - Ω 17.97 Ω
Z =
m
106
⇒
17,97 0,82 Ω 14,74 Ω
R =
m
X = 17,97
m

Cable

Length = 5 km
Ω
------- -
R = 0,27
c
km
mH
-------- -
L = 0,33
c
km

Secondary side

(
Z = 1,35 +
1
Current for the secondary side:
I = I = 106 A
2 n
Thus, the minimum voltage for the secondary side equals
3 106 A 19.38 Ω 3558 V ⋅
U =
2
The secondary voltage of the transformer is thus chosen as follows
U = 3560 V
N2

Primary side

The primary voltage of the transformer is
⋅
U = 0,9 690 V
N1
3300
≈
⋅
3
⋅ ≈
2
⋅ Ω 10,29 Ω
1 0,82 –
⇒ 5 0,27 Ω ⋅
R =
c
2 π 50 0,33 10 ⋅
⇒
L =
c
2
) (
14,74 + 0,52 + 10,29
⋅ ≈
≈
620 V
≈
≈ 1,35 Ω
3 –
⋅ ⋅ ⋅ ≈ 0,52 Ω
2
) Ω 19,38 Ω ≈
Appendix – Step-up applications
37