44
MG.30.A7.02 - VLT
®
is a registered Danfoss trademark
The tables on pp. 25-29 show the output
loss P
2
(W) from the VLT
®
3000. The
maximum cooling air temperature t
IN,MAX
is
40° C at 100% load (of rated value).
Mechanical installation
Heat emission from
the VLT
®
3000
1. Add up the values of P
Φ
for all the
VLT
®
’s to be installed in the same panel.
The highest cooling air temperature (t
IN
)
occurring must be lower than t
IN,MAX
(40° C).
The day/night average must be 5° C
lower (VDE 160).
The outlet temperature of the cooling air
may not exceed: t
OUT,MAX
(45° C).
2. Calculate the permitted temperature
difference between the cooling air
temperature (t
IN
) and the cooling air
outlet temperature (t
OUT
):
∆
t = 45° C-t
IN
= 1388 m
3
/h
5
2240 x 3.1
1.
∑
P
Φ
= 8 x P
Φ
W = t
IN, MAX
= 2240 W.
2.
∆
t = 45°C-t
IN
= 45°C-40°C= = 5°K.
2. Quantity of air (at 40°C) =
Example:
Ventilation of VLT
®
units
when panel-mounted
The quantity of air needed to cool the
VLT
®
frequency converters can be calcu-
lated as follows:
The total output loss and the total air
requirement at 100% load for 8 VLT
®
type
3006 units mounted in the same panel.
Cooling air temperature (t
IN
) = 40° C and
max. cooling air outlet temperature
(t
OUT,MAX
) = 45° C.
P
Φ
= 280 W and t
IN, MAX
= 40° C.
3. Calculate the necessary quantity of air
in m
3
/h =
The outlet from the fan must be located
above the highest mounted frequency
converter.
Remember to take pressure drops over
filters into account and that the pressure
decreases as the filters are choked.
∑
P
Φ
x 3.1
∆
t
Insert
∆
t in Kelvin
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