REVEX
3PH from 120A to 210A
User’s manual
17
6.7 Calculating flow capacity of the fan
All the thyristor units when are in conduction produces power loss that is dissipated inside cubicle in terms of
heating. Due to this fact the internal temperature of cubicle is higher than ambient temperature. To be cooled
the thyristor need of fresh air cooling and to do it is normally used a fan mounted on the front door or on the
roof of the cabinet.
Procedure to size
Fan air mass flow (V)
:
see power loss or each thyristor and fuse mounted indicated in the
manual related to the current (Output feature and Internal fuse Chapter).
Qv
= total power losses (w)
Altitude
(thy fuse power loss)
0:100
meters f = 3.1 m3k/Wh
ta
= ambient temperature (°C)
100:250 meters f = 3.2 m3k/Wh
tc
= cabinet temperature (°C)
250:500 meters f = 3.3 m3k/Wh
V
= fan air mass flow (m3/h)
500:750 meters f = 3.4 m3k/Wh
f
= altitude coefficient (see table on right)
The formulas used are for information only and is not a substitute for a proper thermal rating
done by a qualified person.
6.5 Fan Specification
Supply: 24Vdc
Power 21W (7W for 3 Fan)
6.6 Derating Curve
The nominal current of the units in specification are referred to continuous service at 40°C ambient temperature.
For higher temperature multiply the nominal current times derating coefficient K below represented:
l max = l nominal x K
1
15 20 25 30 35 40 45 50 55
1,2
1
0,8
0,6
0,4
0,2
0
1
1
1
1
0,9
0,8
K
Derating
CABINET TEMPERATURE °C
For higher cabinet
temperature
(more than 50°C)
contact the producer
of the unit
V=f * Qv
tc-ta
