Danfoss FC 300 Design Manual page 98

4 AutomationDrive FC 300 Selection
4.9.3 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
current (I ) should be derated in accordance with the diagram shown.
out
4
Figure 4.38: Derating of output current versus altitude at T
contact Danfoss 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
available. At a temperature of 107°F [41.7°C], 100% of the rated output current is available.
Derating of output current versus altitude at T
4-38
for frame sizes A, B and C. At altitudes above 6,600 feet [2 km], please
AMB, MAX
for frame sizes D, E and F.
AMB, MAX
MG.33.BC.22 - VLT ® is a registered Danfoss trademark
FC 300 Design Guide
) or max. output
AMB
- 3.3 K), 91% of the rated output current is
AMB, MAX