60 AVM - Pulse Width Modulation, 525–690 V
Figure 3.17: Derating of I
out
for different T
AMB, MAX
for en-
closure E and F at 690 V, using 60 AVM in Normal torque
mode (110% over torque).
SFAVM - Stator Frequency Asyncron Vector Modulation
Figure 3.18: Derating of I
out
for different T
AMB, MAX
for en-
closure E and F at 690 V, using SFAVM in Normal torque
mode (110% over torque).
3.5.3 Derating for Low Air Pressure
The cooling capability of air is decreased at a lower air pressure.
At an altitude lower than 3,280 ft [1,000 m], no derating is necessary, but above 3,280 ft [1,000 m], the ambient temperature (T
AMB
) or max. output
current (I
out
) should be derated in accordance with the diagram shown.
Figure 3.19: Derating of output current versus altitude at T
AMB, MAX
for frame sizes A, B and C. At altitudes above 6,600 ft [2 km], please
contact Danfoss Drives regarding PELV.
An alternative is to lower the ambient temperature at high altitudes and thereby ensure 100% output current at high altitudes. As an example of how to
read the graph, the situation at 6,600 ft [2 km] is elaborated. At a temperature of 113°F [45°C] (T
AMB, MAX
- 3.3 K), 91% of the rated output current is
available. At a temperature of 107°F [41.7°C], 100% of the rated output current is available.
3 VLT AQUA Selection VLT
®
AQUA Drive Design Guide
3-28
MG.20.N5.22 - VLT
®
is a registered Danfoss trademark
3
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