1.8 Special Conditions
1.8.1 Derating for Ambient Temperature
and Switching Frequency
The ambient temperature measured over 24 hours should
be at least 9
°
F [5
°
C] lower than the maximum ambient
temperature. If the adjustable frequency drive is operated
at a high ambient temperature, the continuous output
current should be decreased. For derating curves, see
VLT
®
Compressor Drive CDS 803 Design Guide
.
1.8.2 Derating for Low Air Pressure
The cooling capability of air is decreased at low air
pressure. For altitudes above 6,600 feet [2 km], contact
Danfoss regarding PELV. Below 3,300 ft [1000 m] altitude
no derating is necessary, but above 3,300 ft [1000 m] the
ambient temperature or the maximum output current
should be decreased. Decrease the output by 1% per
330 ft [100 m] altitude above 3,300 ft [1000 m] or reduce
the maximum ambient temperature by 2°F [1
°
C] per 660 ft
[200 m].
1.9 Options for VLT
®
Compressor Drive CDS
803
For options, see the
VLT
®
Compressor Drive CDS 803 Design
Guide
.
Quick Guide
Quick Guide
MG18M122
Danfoss A/S © Rev. 08/2014 All rights reserved.
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