Derating; Ambient Temperature Derating; Altitude Derating - ABB ACS880-104 Hardware Manual

Derating

￭

Ambient temperature derating

In the temperature range +40...50 °C (+104...122 °F), the rated output current is derated
by 1 percentage point for every added 1 °C (1.8 °F). The output current can be calculated
by multiplying the current given in the rating table by the derating factor (k):
k
1.00
0.90
0.80
+40 °C
+104 °F
￭

Altitude derating

At altitudes from 1000 to 4000 m (3281 to 13123 ft) above sea level, the output current
derating is 1 percentage point for every added 100 m (328 ft). For example, the derating
factor for 1500 m (4921 ft) is 0.95.
If ambient temperature is below +40 °C (+104 °F), the derating can be reduced by 1.5
percentage points for every 1 °C (1.8 °F) reduction in temperature. A few altitude derating
curves are shown below.
4000 m
13123 ft
3500 m
11429 ft
3000 m
9842 ft
2500 m
8202 ft
2000 m
6562 ft
1500 m
4921 ft
1000 m
3300 ft
+20 °C
+68 °F
Derating factor 1.00
Derating factor 0.95
Derating factor 0.90
+50 °C T
+122 °F
+25 °C +30 °C
+77 °F +86 °F
0.80
0.85
0.90
0.95
1.00
+35 °C
+95 °F
Technical data 279
+40 °C
+104 °F