4.1.7 Derating for Ambient Temperature
The ambient temperature (T
AMB,MAX
) is the maximum
temperature allowed. The average (T
AMB,AVG
) measured over
24 hours must be at least 5º C lower.
If FCM 300 Series is operated at temperatures above 40º C,
a derating of the continuous output current is necessary.
Illustration 4.2
4.1.8 Derating for Air Pressure
By altitudes above 2 km, please contact Danfoss Drives
regarding PELV.
Below 1000 m altitude no derating is necessary.
Above 1000 m the ambient temperature (T
AMB
) or max.
output current (I
VLT,MAX
) must be derated in accordance
with the following diagram:
1.
Derating of output current versus altitude at T
AMB
= max. 40°C
2.
Derating of max. T
AMB
versus altitude at 100%
output current.
Illustration 4.3
4.1.9 Derating for Running at Low Speed
When a centrifugal pump or a fan is controlled by an FC
motor, it is not necessary to reduce the output at low
speed because the load characteristic of the centrifugal
pumps/fans, automatically ensures the necessary reduction.
FC motors running constant load torque applications
continuously at low speed must be derated (see
) or an independent fan must be used (motor
cooling method 2).
Nominal torque (100%) can be yielded up to 15 min and
at a duty cycle up to 25% at low speed.
Illustration 4.4 Derating for Running at Low Speed
4.1.10 Derating for High Switching
Frequency
The FCM 300 Series motor can use two different PWM
schemes, SFAVM and 60° AVM. Factory setting is SFAVM.
The PWM scheme can be changed in parameter 446.
Below 25 Hz motor speed the FCM 300 Series motor
automatically change to SFAVM.
Factory setting of the switching frequency is 4000 Hz. It
can be changed between 2 and 14 kHz in parameter 411.
A higher switching frequency leads to a quieter running
unit but higher losses in the electronics of the FC motor
and makes an appropriate derating necessary.
See
All about FCM 300
VLT
®
DriveMotor FCM Series
MG03BA02 - VLT
®
is a registered Danfoss trademark
79
4
4
Содержание VLT Brook Crompton Motor FCM 300
Страница 1: ...MAKING MODERN LIVING POSSIBLE Design Guide VLT Brook Crompton Motor FCM 300 www danfoss com drives...
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