ABB PVS800-57B, Maintenance Manual, Page: 36 / 78

36 Mechanical installation

Preventing the recirculation of hot air
To prevent hot air recirculation outside the inverter, make sure that the exhaust air flows
away from the air inlets. Make sure that the hot air from the inverter module cabinet does
not flow into the adjacent cabinets.

Ventilation duct at the air outlet of the cabinet
The ventilation system must keep the static pressure in the air outlet duct sufficiently below
the pressure of the room where the inverter is located in order that the cabinet fans can
produce the required air flow through the cabinet. Make sure that no dirty or moist air flows
back to the inverter, even during off-time or when you do maintenance on the inverter.
Calculating the required static pressure difference
You can calculate the required static pressure difference between the exit air duct and the
inverter installation room as follows:
where
Example
The cabinet has 3 exit openings of 315 mm diameter. The rated air flow of the cabinet is
4650 m
3
/h =1.3 m
3
/s.
A
c
= 3 • 0.315
2
• / 4 = 0.234 m
2
v
m
= q / A
c
= 1.3 / 0.234 = 5.5 m/s
p
d Dynamic pressure
Air density (kg/m
3
)
v
m Average air velocity in the exit duct(s) (m/s)
q
Rated air flow of the inverter (m
3
/s)
A
c Cross-sectional area of the exit duct(s) (m
2
)
X
X
X
p
s
= (1.5…2) • p
d
p
d
= 0.5 •
• v
m
2
v
m
= q / A
c