Special Conditions; Purpose Of Derating; Derating For Ambient Temperature - Danfoss VLT FC51 Design Manual

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4.2 Special Conditions

4.2.1 Purpose of Derating

Take the purpose of derating into account when using the
frequency converter at low air pressure (heights), 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.

4.2.2 Derating for Ambient Temperature

Derating for ambient temperature and IGBT Switching.
The ambient temperature measured over 24 hours should
be at least 5 °C lower than the max. ambient temperature.
If the frequency converter is operated at high ambient
temperature, the continuous output current should be
decreased. The frequency converter has been designed for
operation at max. 50 °C ambient temperature with one
motor size smaller than nominal. Continuous operation at
full load at 50 °C ambient temperature reduces the lifetime
of the frequency converter.
M1 200 V
Iout [%]
110 %
100 %
90 %
80 %
70 %
60 %
50 %
40 %
30 %
20 %
10 %
0
0 2 4 6 8
Illustration 4.34 M1 200 V
M1 400 V
Iout [%]
110 %
100 %
90 %
80 %
70 %
60 %
50 %
40 %
30 %
20 %
10 %
0
0 2 4 6 8
Illustration 4.35 M1 400 V
®
VLT Micro Drive FC 51 Design Guide
40 ℃
45 ℃
50 ℃
10 12 14 16 fsw [kHz]
40 ℃
45 ℃
50 ℃
10 12 14 16 fsw [kHz]
MG02K302 - Rev. 2013-12-03
M2 200 V
Iout [%]
110 %
100 %
90 %
80 %
70 %
60 %
50 %
40 %
30 %
20 %
10 %
0
0 2 4 6 8
Illustration 4.36 M2 200 V
M2 400 V
Iout [%]
110 %
100 %
90 %
80 %
70 %
60 %
50 %
40 %
30 %
20 %
10 %
0
0 2 4 6 8
Illustration 4.37 M2 400 V
M3 200 V
Iout [%]
110 %
100 %
90 %
80 %
70 %
60 %
50 %
40 %
30 %
20 %
10 %
0
0 2 4 6 8
Illustration 4.38 M3 200 V
40 ℃
45 ℃
50 ℃
10 12 14 16 fsw [kHz]
40 ℃
45 ℃
50 ℃
10 12 14 16 fsw [kHz]
40 ℃
45 ℃
50 ℃
10 12 14 16 fsw [kHz]
37
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