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 lower than the maximum ambient
temperature that is specified for the frequency converter. If
the frequency converter is operated at a high ambient
temperature, the continuous output current should be
decreased. For derating curve, see VLT
®
HVAC Basic Drive
Design Guide.
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).
Specifications Quick Guide
MG18A602 Danfoss A/S © 08/2014 All rights reserved. 49
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