AC Axial-flow Fans
Common Information
M-45
Ot
h
e
rs
(2) Noise Countermeasures
The cooling effect and noise levels of Axial-flow Fans are greatly
affected by the mounting conditions. Take the points listed below into
account when installing the Fans.
Maintain as much clearance as possible (L) between the Fan inlet
and the cooled object.
(If the cooled object occupies about the same surface area as the
Fan on a flat surface, a distance of approximately 10 cm is appropri-
ate.)
The diameter of the Fan installation hole (D
2
) should be larger than
the diameter of the Fan (D
1
).
(3) Cooling Effect
Avoid rapid changes in air flow direction or air-flow cross-section
which reduce the cooling effect.
When installing the Fan, keep the clearance at the outlet side as
small as possible. (If there is a large clearance at the outlet side, it
may not be possible to obtain a sufficient cooling effect.)
(4) Installation
The Fan can be mounted with bolts through only one flange (single-
flange mounting) or with through-bolts through both flanges (double-
flange mounting). Take care not to distort the frame when using dou-
ble-flange mounting.
Tighten the bolts to a torque of approximately 0.44 N·m when install-
ing the Fan.
Flow Rate and Static Pressure
The characteristic graphs provided for each of the models represent
the average of actual measurement data obtained under the mea-
surement conditions given below. They are provided as reference for
determining the Fan most suitable for the type of cooling required;
the actual characteristics may differ from the values represented in
the graphs.
A simple explanation of the flow rate/static pressure characteristics
and the methods of measuring them is given below.
Maximum Static Pressure, Ps max (flow rate = 0):
Fully close the damper. Take the pressure difference between cham-
ber B and ambient pressure (Ps). The maximum value of the pres-
sure difference (Ps) is the maximum static pressure (Ps max).
Intermediate Region, (Q, Ps):
Adjust the auxiliary blower to change the static pressure (Ps). Mea-
sure the pressure difference between chamber A and chamber B
(Pd). Calculate the flow rate (Q).
Maximum Flow Rate, Q max (static pressure = 0):
Fully open the damper and adjust the auxiliary blower to set the
static pressure to zero (0). Measure the pressure difference between
chamber A and chamber B (Pd). Take the flow rate (Q) calculated at
this point as the maximum flow rate (Q max).
Fan Operating Point:
A Fan installed in equipment operates near the point where the Fan
characteristic curve crosses the system impedance curve.
Note:
The maximum flow rate and maximum static pressure do not
indicate the Fan operating point when it is installed in equip-
ment. However, these characteristics are important for com-
paring Fan performances and for selecting Fans.
Measurement Conditions
Fan
Cooled body
L
Fan
Panel
D
1
D
2
D
1
: Fan installation hole diameter
D
2
: Fan diameter
D
1
> D
2
Fan
Panel
Fan
Panel
L (ideally zero (0))
Single-flange
mounting
Double-flange
mounting
Number of Fans tested
Ambient conditions
Measurement device
5
Temperature: 23
±
2
°
C
Humidity: 65
±
5%
Measurement was performed using the multi-nozzle
double chamber method based on AMCA (Air Moving
Condition Association, U.S.A.) standards 270 to 274.
