Danfoss VLT HVAC Drive - 8.2.3. Derating for Low Air Pressure

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 a lower air pressure.
At altitudes higher than 6,600 feet [2 km], please contact Danfoss Drives regarding PELV.
At an altitude lower than 3,280 ft [1,000 m], no derating is necessary; but at an altitude higher
than 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.
8. Specifications VLT
®
HVAC Drive Instruction Manual
150 MG.11.A4.22 - VLT
®
is a registered Danfoss trademark
8