Danfoss vlt AQUA Instruction Manual page 173

®
VLT AQUA Drive
Instruction Manual
10.2 Special Conditions
10.2.1 Purpose of derating
Derating must be taken into account when using the adjustable frequency drive at low air pressure (high elevations), at low speeds, with long motor
cables, cables with a large cross-section or at high ambient temperature. The required action is described in this section.
10.2.2 Derating for Ambient Temperature
The average temperature (T
AMB, AVG
(T ).
AMB,MAX
If the adjustable frequency drive is operated at high ambient temperatures, the continuous output current should be decreased.
The derating depends on the switching pattern, which can be set to 60 AVM or SFAVM in parameter 14-00.
A enclosures
60 AVM - Pulse Width Modulation
Figure 10.1: Derating of I
out
closure A, using 60 AVM
In enclosure A, the length of the motor cable has a relatively high impact on the recommended derating. Therefore, the recommended derating for an
application with max. 32 ft [10 m] motor cable is also shown.
Figure 10.3: Derating of I
out
closure A, using 60 AVM and maximum 32 ft [10 m] motor
cable
) measured over 24 hours must be at least 9°F [5°C] lower than the maximum allowed ambient temperature
for different T for en-
AMB, MAX
for different T for en-
AMB, MAX
®
MG.20.M5.22 - VLT is a registered Danfoss trademark
SFAVM - Stator Frequency Asyncron Vector Modulation
Figure 10.2: Derating of I
out
closure A, using SFAVM
Figure 10.4: Derating of I
out
closure A, using SFAVM and a maximum of 32 ft [10 m]
motor cable
10 Specifications
for different T for en-
AMB, MAX
for different T for en-
AMB, MAX
10-17
10