10
Project planning
Selecting an inverter
Operating Instructions – MOVIMOT
®
flexible
295
10.7.2
Derating
Due to the following operating and ambient conditions, a reduction of the output cur-
rent may be necessary.
Derating due to the rotary field frequency
The specified nominal output current I
N
of the inverter is the rms value. The increased
load on the power semiconductors has to be considered especially for slow rotating
fields and rotating fields at standstill. In case of a rotating field at standstill, direct cur-
rent that can correspond to the peak value of the sine current depending on the phase
position is flowing.
It is particularly important to consider output frequencies f
A
< 3 Hz.
0
50
100
150
200
250
300
0
1
2
3
4
5
[2]
[1]
% I
N
f /Hz
A
31277066635
[1]
Continuous output current at f
PWM
= 4 kHz
[2]
Temporary overload current
Derating depending on the installation altitude
Observe the derating according to chapter "Mechanical installation" > "Setting up the
device" > "Derating depending on the installation altitude".
Derating depending on the ambient temperature
Also observe derating as specified in chapter "Technical data and dimension sheets" >
"Technical data" > "Derating factors" > "Derating depending on the ambient tempera-
ture".
29129451/EN – 12/2019