Vacon NX Active Front End, Руководство пользователя

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4
vacon • 44 Active Front End (AFE)
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4.16 Derating
The output power has to be derated if one of following cases:
• Ambient temperature is more than 40 ºC.
• Installation altitude is more than 1000 m.
4.16.1 Ambient Temperature
The power rating of the Active Front End unit is valid for an ambient temperature of 40 ºC. If the
device is to be used in higher ambient temperatures, its power rating must be subjected to derating.
The derating coefficient is 1.5%/1 ºC, for ambient temperatures not exceeding 50 ºC. The reduced
power is calculated using the formula:
Figure 23. Derating as the ambient temperature
4.16.2 Installation altitude
The standard power ratings of the Active Frond End unit are valid for a maximum installation
altitude of 1 000 m. If the device is to be used in higher installation altitudes, its power ratings must
be subjected to derating. The derating coefficient is 1.5% per 100 m. The power rating of the device
can be reduced to a maximum installation altitude of 4000 m (500 V) and 2000 m (690 V). The reduced
power can be calculated using the formula:
P
de
=
P
n
*((100% - (
t
- 40 ºC)*X)/100)
P
n
= nominal power of the unit
t = ambient temperature
x = derating coefficient
P
de
= p
n
*((100% -(
h
inst
- h
base
)*X)/100)
P
n
= nominal power of the unit
h
inst
= intended installation altitude
h
base
= 1,000 m
x = derating coefficient
50
60
70
80
90
100
110
0 10 20 30 40 50 60
11167.emf
Loadabi
li
ty, %
Ambient temperature, °C
Derating as a function of ambient temperature
Loadability %