3-5
3.6 Alignment
The fan is aligned at the factory before shipping, but should be realigned after installation.
Warning
Alignment work should be carried out without the belt guard and the
shaft coupling guard. So they must be re-installed before starting the
operation.
If the fan is operated without the belt guard and/or the shaft coupling,
you may be caught by the belt/shaft and injured.
Caution
Incorrect alignment may damage the equipment, or cause vibrations
and noise. Align the fan correctly.
3.6.1. Alignment of belt drive type
(1) Place a ruler or a piano wire onto the outer surfaces of the
V-belt pulleys on both the fan and motor sides, and check
and adjust it such that the surfaces of the pulleys are on a
straight line.
(2) If you can depress the middle of the V-belt with your finger
up to about the same depth as the thickness of the V-belt,
the tension of general V-belts should be appropriate.
Use the slide base of the motor to adjust the tension of the
V-belt.
(3) Stretch the high tension V-belts slightly tighter than general
V-belts. Too loose tension may cause the belt to slip during
startup, and excessive tension may apply a large load to
the shaft and bearing, thus resulting in failure.
(4) Since V-belts tend to loosen at the early stages of its use,
ensure to readjust it in several days of use.
[Procedure]
Obtain the deflection δ: 0.016ℓ. (ℓ: Distance between pulleys)
Then use a tension meter to produce the standard deflection (δ mm) in the middle of the V-belt.
Re-tension the belt (or adjust the tension) such that the deflection load at that time corresponds to
the value given in the following table.
Deflection load Td for each V-belt type and small pulley OD
V-belt
type
Range of small pulley
outside diameter
(mm)
Deflection load of new
belt
N/belt (kgf/belt)
Deflection load after
re-tension
N/belt (kgf/belt)
65 - 80
81 - 90
91 - 105
A
106 -
9.8 (1.0)
11.8 (1.2)
13.7 (1.4)
15.7 (1.6)
7.8 (0.8)
8.8 (0.9)
10.8 (1.1)
11.8 (1.2)
115 - 135
136 - 160
B
161 -
17.7 (1.8)
22.6 (2.3)
24.5 (2.5)
13.7 (1.4)
17.7 (1.8)
18.6 (1.9)
175 - 205
206 - 255
C
256 -
35.3 (3.6)
42.2 (4.3)
50.0 (5.1)
27.5 (2.8)
32.4 (3.3)
38.2 (3.9)
67 - 90
91 - 115
116 - 150
3V
151 - 300
21.6 (2.2)
25.5 (2.6)
29.4 (3.0)
33.3 (3.4)
17.7 (1.8)
19.6 (2.0)
22.6 (2.3)
25.5 (2.6)
180 - 230
231 - 310
5V
311 - 400
74.5 (7.6)
90.2 (9.2)
105.9 (10.8)
57.9 (5.9)
69.6 (7.1)
82.4 (8.4)
The values in ( ) are expressed in the traditional unit system and
shown for reference.
Tension meter
Ruler or piano wire
Make them parallel
V-belt
pulley
Motor
Fan
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