Danfoss VLT HVAC - Page 140

B enclosures
60 PWM - Pulse Width Modulation
Illustration 8.5: Derating of I
out
for different T
AMB,
MAX
for enclosure B, using 60 PWM in Normal tor-
que mode (110% over torque)
SFAVM - Stator Frequency Asyncron
Vector Modulation
Illustration 8.6: Derating of I
out
for different T
AMB,
MAX
for enclosure B, using SFAVM in Normal torque
mode (110% over torque)
C enclosures
60 PWM - Pulse Width Modulation
Illustration 8.7: Derating of I
out
for different T
AMB,
MAX
for enclosure C, using 60 PWM in Normal tor-
que mode (110% over torque)
SFAVM - Stator Frequency Asyncron
Vector Modulation
Illustration 8.8: Derating of I
out
for different T
AMB,
MAX
for enclosure C, using SFAVM in Normal torque
mode (110% over torque)
8.2.3. 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 8.9: Derating of output current versus altitude at T
AMB, MAX
. By altitudes above 2 km, please
contact Danfoss Drives regarding PELV.
8. Specifications VLT
®
HVAC Drive Operating Instructions
140 MG.11.A4.02 - 09.10.06. VLT
®
is a registered Danfoss trademark
8