Specifications

Note 1 The fixed disc of the pulley must be placed on the motor side.
(Do not place the sliding piece on the motor side.) See Figure 1.
Note 2 After adjusting the width of the variable-width pulley, also adjust the alignment (centering).
(Using a ruler, align the pulleys so that the width of 1 and 2 in Figure 2 is the same.)
Note 3 The pulley groove width in Table 1 are reference values. Adjust the PC ø of the variable-width
pulley by applying the specified number of turns.
74
• Adjusting the variable-width pulley
Adjust the PC ø of variable-width pulley according to the procedures described below.
1) Loosen the setscrew holding the fixed and the sliding discs in place.
2) Turn the sliding disc counter-clockwise until no gap is left (0 mm) between the fixed and the sliding
discs.
3) Select the PC ø in Table 1 that is closest to the one to be used. Once the PC ø has been selected,
see the number of turns to apply that corresponds to the selected PC ø to determine how many turns
to apply to the sliding disc.
4) Fix the fixed and the sliding discs in place with the setscrew. (Tightening torque:13.5 N·m)
Let the tip of the setscrew rest in the V-shaped notch on the flat part of the fixed disc to hold the
sliding disc in position.
Apply Screw Lock (field supplied) to the setscrew to keep it from coming unscrewed. (Screwlock:
ThreeBond 1322N or its equivalent)
5) Perform a test run, and check that the pulley is not loose. When the test run is completed, check the
setscrew for looseness.
Note: Check that the desired rotation speed is in the operating range as indicated in the fan performance
diagram. (If the rotation speed exceeds the operating range, the overcurrent relay on the fan will trip.)
Important notes on pulleys and pulley belts
CAUTION
(Figure 2) Adjusting the horizontal alignment of the variable-width pulley
(Figure 1) Variable-width pulley
(Table 1) PC ø of variable-width pulleys
0
140.0
150.0
(0)
1/4
138.8
148.8
(0.4)
1/2
137.5
147.5
(0.8)
3/4
136.3
146.3
(1.1)
1
135.1
145.1
(1.5)
1·1/4
133.9
143.9
(1.9)
1·1/2
132.6
142.6
(2.3)
1·3/4
131.4
141.4
(2.6)
2
130.2
140.2
(3.0)
2·1/4
129.0
139.0
(3.4)
2·1/2
127.7
137.7
(3.8)
2·3/4
126.5
136.5
(4.1)
3
125.3
135.3
(4.5)
3·1/4
124.1
134.1
(4.9)
3·1/2
122.8
132.8
(5.3)
3·3/4
121.6
131.6
(5.6)
4
120.4
130.4
(6.0)
4·1/4
119.1
129.1
(6.4)
4·1/2
117.9
127.9
(6.8)
4·3/4
(7.1)
116.7
126.7
FAN side pulley
Variable width pulley
Ruler
Rotation direction of the pulley while in use
Fixed disc must be placed
on the motor side.
Fixed disc of the pulley
Sliding disc
Screw (M8)
(Pointed Allen screw)
Fixed disc of
the pulley
Flat part
The fixed disc has threads
and the sliding disc has grooves.
Pulley distance
1
2
1 = 2
The fixed and the sliding discs can be fixed in position relative to
each other by threading the setscrew through one of the two
holes on the sliding disc so that the tip of the setscrew rests in the
V-shaped notch on either of the two flat parts of the fixed disc.
Number of turns to
apply to the sliding disc
PC ø of variable-width
pulleys for 1.5 kW motor
PC ø of variable-width
pulleys for 2.2 kW motor
Pulley distance (mm)