Danfoss VLT AQUA Drive Series - Page 63

60 AVM - Pulse Width Modulation, 525 - 690 V
Illustration 3.17: Derating of I
out
for different T
AMB, MAX
for
enclosure E and F at 690 V, using 60 AVM in Normal torque
mode (110% over torque).
SFAVM - Stator Frequency Asyncron Vector Modulation
Illustration 3.18: Derating of I
out
for different T
AMB, MAX
for
enclosure 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 lower air pressure.
Below 1000 m altitude no derating is necessary but above 1000 m the ambient temperature (T
AMB
) or max. output current (I
out
) should be derated in
accordance with the shown diagram.
Illustration 3.19: Derating of output current versus altitude at T
AMB, MAX
for frame sizes A, B and C. At altitudes above 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 2 km is elaborated. At a temperature of 45° C (T
AMB, MAX
- 3.3 K), 91% of the rated output current is available. At a
temperature of 41.7° C, 100% of the rated output current is available.
VLT
®
AQUA Drive Design Guide 3 VLT AQUA Selection
MG.20.N5.02 - VLT
®
is a registered Danfoss trademark 63
3