Calculating The Required Static Pressure Difference; Arc Welding - ABB ACS880-07 Hardware Manual

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:
p = (1.5...2) • p
s
where
p = 0.5 •
• v
d
m
v = q / A
m c
p
d Dynamic pressure
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
c Cross-sectional area of the exit duct(s) (m
Example
The cabinet has 3 exit openings of 315 mm diameter. The rated air flow of the cabinet is
3 3
4650 m /h =1.3 m /s.
2
A = 3 • 0.315 • / 4 = 0.234 m
c
v = q / A = 1.3 / 0.234 = 5.5 m/s
m c
2
p = 0.5 • • v = 0.5 • 1.1 • 5.5
d m
The required pressure in the exit air duct is then, 1.5...2 • 17 Pa = 26...34 Pa, below the
pressure in the room.
For more information: Contact ABB.

Arc welding


Fastening the cabinet by arc welding is not recommended. However, if the arc welding is
the only mounting option, proceed as follows: Connect the return conductor of the welding
equipment to the cabinet frame at the bottom within 0.5 meters (1.5 ft) of the welding point.
Note: The thickness of the zinc coating of the cabinet frame is 100 to 200 micrometers.
WARNING! Make sure that the return wire is connected correctly. Welding current
must not return via any component or cabling of the drive. If the welding return
wire is connected improperly, the welding circuit can damage electronic circuits in
the cabinet.
WARNING! Do not inhale the welding fumes.
d
2
3
)
3
/s)
2
2
= 17 Pa
Mechanical installation 63
2
)