Ip54R (B059); Calculating The Required Static Pressure Difference; Example - ABB ACS800-07 Manual

IP54R (B059)

This option provides the degree of protection of IP54R (UL type 12) with a collar for
fitting an air outlet duct. The collar is located on the cabinet roof either directly or on
the extra fan housing (ACS800-07 frames R7 and R8). The option equips the
cabinet air inlets with filter housings containing folded board air filter mats between
the inner metallic grating and the outer plastic grating.
Note: The ventilation system must keep the static pressure in the air outlet duct
sufficiently below the pressure of the room where the drive is located in order that
the cabinet fans can produce the required air flow through the cabinet. Ensure that
no dirty or moist air is able to flow backward to the drive in any case, even during off-
time or while servicing the drive or the ventilation system.

Calculating the required static pressure difference

The required static pressure difference between the exit air duct and the drive
installation room can be calculated as follows:
where

Example

The cabinet has 3 exit openings of 315 mm diameter. The rated air flow of the
cabinet is 4650 m
A = 3 • 0.315
c
v = q / A
m
p = 0.5 •
d
The required pressure in the exit air duct is then, 1.5...2 • 17 Pa = 26...34 Pa, below
the pressure in the room.
More information: Contact ABB.
p = (1.5...2) • p
s d
2
p = 0.5 •
• v
d
m
v = q / A
m c
p dynamic pressure
d
air density (kg/m
v average air velocity in the exit duct(s) (m/s)
m
q rated air flow of the drive (m
A cross-sectional area of the exit duct(s) (m
c
3
/h =1.3 m
2
• / 4 = 0.234 m
= 1.3 / 0.234 = 5.5 m/s
t
2
• U = 0.5 • 1.1 • 5.5
m
3
)
3
/s)
3
/s.
2
2
= 17 Pa
2
)
Degree of protection (B)
15