Frame Sizes R5 And R6; Calculation Example - ABB ACS800-U1 Hardware Manual

Frame sizes R5 and R6

Choose between gG and aR fuses according to the table under
selecting between gG and aR fuses
checking that the short-circuit current of the installation is at least the value given in
the fuse table. The short-circuit current can be calculated as follows:
I
k2-ph
where
I
= short-circuit current in symmetrical two-phase short circuit
k2-ph
U
= network line-to-line voltage (U)
R
= cable resistance (ohm)
c
2
Z U S
= z · /
k k N
z = transformer impedance (%)
k
U
= transformer rated voltage (V)
N
S
= nominal apparent power of the transformer (kVA)
N
X
= cable reactance (ohm)
c

Calculation example

Drive:
•
ACS800-01-0075-3
•
supply voltage
Transformer:
•
S
rated power
N
•
rated voltage (drive supply voltage)
•
transformer impedance z
Supply cable:
•
length = 170 m
•
resistance/length = 0.398 ohm/km
•
reactance/length = 0.082 ohm/km.
Z
k
(page 115), or verify the operating time by
U
=
2
2 · R + (Z
c
= transformer impedance (ohm)
N
= 600 kVA
= 7.2%.
k
2
U
(430 V)
N
·
= z · = 0.072
k
S
600 kVA
N
ohm
m · 0.398
R = 170
c
m · 0.082
X = 170
c
2
+ X )
k c
U
= 430 V
N
2
= 22.19 mohm
= 67.66 mohm
km
ohm
= 13.94 mohm
km
Technical data 111
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