Technical data
112
Ambient temperature derating
In the temperature range +40…55 °C (+104…131 °F), the rated output current is derated by 1% for
every added 1 °C (1.8 °F) as follows:
Altitude derating
At altitudes from 1000 to 4000 m (3300 to 13123 ft) above sea level, the derating is 1% for every 100 m
(328 ft). For a more accurate derating, use the DriveSize PC tool.
Fuses (IEC)
gG and aR fuses for protection against short-circuit in the input power cable or drive
are listed below. Either fuse type may be used if it operates rapidly enough. Choose
between gG and aR fuses according to the table under Quick guide for selecting
between gG and aR fuses on page 115, or verify the operating time by 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:
where
I
k2-ph
= short-circuit current in symmetrical two-phase short-circuit (A)
U = network line-to-line voltage (V)
R
c
= cable resistance (ohm)
Z
k
= z
k
· U
N
2
/S
N
= transformer impedance (ohm)
z
k
= transformer impedance (%)
U
N
= transformer rated voltage (V)
S
N
= nominal apparent power of the transformer (kVA)
X
c
= cable reactance (ohm).
Ambient temperature
Derating factor
1.00
0.85
+40 °C +55 °C
+104 °F +131 °F
I
k2-ph
=
2 ·
R
c
2
+ (Z
k
+ X
c
)
2
U
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