Nord Drivesystems SK 180E Series, User Manual

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8 Additional information
BU 0180 en-4118 189
8.4.4 Reduced output current due to mains voltage
The devices are designed with thermal characteristics according to the nominal output currents.
Accordingly, for lower mains voltages, higher currents cannot be taken off in order to maintain the
stated power constant. For mains voltages above 400 V there is a reduction of the permissible
continuous output current, which is inversely proportional to the mains voltage, in order to compensate
for the increased switching losses.
1.2
0.4
k Unetz Unetz ( )
480 320 Unetz
320 340 360 380 400 420 440 460 480
0.4
0.5
0.6
0.7
0.8
0.9
1
1.1
1.2
Mains voltage [V]
I / I
N
Figure 19: Output current due to mains voltage
8.4.5 Reduced output current due to the heat sink temperature
The temperature of the heat sink in included in the calculation of the reduction of output current, so
that at low heat sink temperatures, a higher load capacity can be permitted, especially for higher pulse
frequencies. At high heat sink temperatures, the reduction is increased correspondingly. The ambient
temperature and the ventilation conditions for the device can therefore be optimally exploited.