￭ Altitude derating
At altitudes above 1000 m (3281 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. The maximum permitted installation altitude is given in the
technical data.
If the surrounding air temperature is less than +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.
1500 m
1000 m
+25 °C +30 °C
+77 °F +86 °F
+40 °C
+104 °F
+35 °C
+95 °F
+20 °C
+68 °F
3300 ft
4921 ft
2000 m
6562 ft
2500 m
8202 ft
3000 m
9842 ft
3500 m
11429 ft
4000 m
13123 ft
1.00
0.95
0.85
0.90
0.80
Derating factor 1.00
Derating factor 0.95
Derating factor 0.90
Derating factor 0.85
Derating factor 0.80
For a more accurate derating, use the DriveSize PC tool.
￭ Switching frequency derating
Switching frequencies other than 1.5 kHz can require output current derating. If you
change the minimum switching frequency with parameter 97.02, calculate the derated
output current by multiplying the current given in the rating table by the derating
factor given in the table below. Changing the switching frequency reference with
parameter 97.01 does not require derating.
Derating factor (k) for the minimum switching frequencies
8 kHz4 kHz2 kHz1 kHz
0.580.780.921
Technical data 181
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