hpmont HD3L Series, User Manual, Page: 14 / 109

Shenzhen Hpmont Technology Co., Ltd. Chapter 1 Safety Information and Precautions
HD3L Series Controller User Manual
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Altitude and derating
In area where altitude exceeds 1000 meters, HD3L should be derating since the heatsink efficiency will
be reduced because of the tenuous air.
The rated value of output current derates by 1% for each 100m increase of the altitude. I.e. for the
altitude of 4000m, derated rate is 30% for rated current of HD3L. Figure 1–1 is the derating curve of
rated current and the altitude.
Figure 1–1 Derating curve of rated current and altitude
70%
100%
1000m 4000m
Altitude
Rated current of HD3L
1