FCM 300 Series
MG.03.B6.02 - VLT is a registered Danfoss trademark
86
Special conditions
■
Derating
The FCM 300 Series motor is thermally protected in
case limits are exceeded. At high temperatures the
switching frequency will be gradually reduced down
to 2 kHz and eventually the motor will trip.
■
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 5ºC lower.
If FCM 300 Series is operated at temperatures above
40 ºC, a derating of the continuous output current is
necessary.
■
Derating for air pressure
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.
■
Derating for running at low speed
When a centrifugal pump or a fan is controlled by a
FC motor, it is not necessary to reduce the output at
low speed because the load characterstic 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
diagram) or an independent fan must be used
(cooling option 6).
Nominal torque (100%) can be yielded up to 15 min
and at a duty cycle up to 25% at low speed.
