Derating; Derating For Ambient Temperature And For Running At Low Speed; Derating For Air Pressure - Danfoss FCM305 56 Instruction Manual

Derating

The FCM 300 Series is thermally protected. At high
temperatures the switching frequency will be
automatically reduced down to 2 kHz. If the
temperature still climbs, the motor will trip.
Derating for ambient temperature
The ambient temperature (T
temperature allowed. The average (T
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 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.

Derating for Air Pressure

Below (3300 ft.) altitude no derating is necessary.
Above (3300 ft.) the ambient temperature (T
max. output current (I
VLT,MAX
accordance with the following diagram:
1) Derating of output current versus altitude at
T = max. 40°C/104
AMB
2) Derating of max. T
AMB
output current.
18-2
) is the maximum
AMB,MAX
)
AMB,AVG
) or
AMB
) must be derated in
o
F
versus altitude at 100%
FCM 300 Series
MG.03.B6.2G - VLT is a registered Danfoss trademark