Special Conditions; Derating For Ambient Temperature And Switching Frequency; Derating For Low Air Pressure And High Altitudes - Danfoss VLT HVAC Basic Drive FC 101 Quick Manual

Specifications

6.3 Special Conditions

6.3.1 Derating for Ambient Temperature
and Switching Frequency
The ambient temperature measured over 24 hours should
be at least 5 °C (9° F) lower than the maximum ambient
temperature that is specified for the adjustable frequency
driver. If the adjustable frequency drive is operated at a
high ambient temperature, the continuous output current
should be decreased. For derating curve, see VLT
Basic Drive Design Guide.
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6.3.2 Derating for Low Air Pressure and
High Altitudes
The cooling capability of air is decreased at low air
pressure. For altitudes above 2000 m (6562 ft), contact
Danfoss regarding PELV. Below 1000 m (3281 ft) altitude,
no derating is necessary. Above 1000 m (3281 ft), the
ambient temperature or the maximum output current
should be decreased. Decrease the output by 1 % per
100 m (328 ft) altitude above 1000 m (3281 ft) or reduce
the maximum ambient temperature by 1 °C per 200 m
(656 ft).
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