Derating Factors; Figure 10-16 Reduktionsfaktoren Durch Die Umgebungstemperatur; Figure 10-17 Derating With Altitude - Siemens MICROMASTER 411 Operating Instructions Manual

Issue 03/01
10.4

Derating Factors

10.4.1 Derating with Temperature
Operation of the inverter outside its recommended ambient operating temperature
would normally cause the inverter to trip with an overtemperature fault code. To
avoid such tripping, the inverter automatically reduces its switching frequency (e.g.
from 16 kHz to 8 kHz), thus reducing the temperature of the heatsink, enabling the
application to continue running trip free. Should the load or ambient temperature
then reduce, the inverter will first check to see if it is safe to increase the switching
frequency again and if considered safe will then do so.

Figure 10-16 Reduktionsfaktoren durch die Umgebungstemperatur

10.4.2 Derating with Altitude
Figure 10-17 shows the permissible rated input voltage and output current for
inverter installations from 500 m to 4000 m above sea level.
Permissible rated input voltage as a
percentage of the nominal voltage
100
90
80
70
60
1000
500

Figure 10-17 Derating with Altitude

MICROMASTER 411 & COMBIMASTER 411
6SE6400-5CA00-0BP0
%
100
80
60
40
20
0
-10 0 10 20
2000 3000 4000
Installation altitude in meters above sea level
Operating Instructions
10 Engineering Information
°C
30 40 50 60 70
Permissible rated output current as a
percentage of the nominal current
100
90
80
70
60
1000 2000 3000
500
4000
135