Figure 27: Wheel-to-Inlet Funnel Relationship—40 to 60
Plenum Fans
Figure 28: Wheel-to-Inlet Funnel Relationship—40 to 60
Plenum Fan
Wheel-Funnel Parameters
Size
A
B
C
40
0 .82
2 .00
4 .88
44
0 .91
2 .25
5 .50
49
1 .00
2 .50
5 .50
54
1 .10
2 .50
5 .50
60
1 .23
3 .00
5 .50
Setscrews on MPQ fan wheels must be installed using a
calibrated torque wrench to the value listed below, ±5% .The
fasteners must be periodically checked to satisfy agency
requirements for components on rotating machinery .
Table 15: Setscrew Torque Specifications—Belt Drive
Plenum Fans Only
Fan Size
Setscrew Size
Torque (ft .-lb)
Aluminum
Steel
13
3/8
19 .2
N/A
15
3/8
19 .2
N/A
16
3/8
19 .2
N/A
18
3/8
19 .2
N/A
20
3/8
19 .2
N/A
22
3/8
19 .2
N/A
24
3/8
19 .2
N/A
27
3/8
19 .2
22
30
1/2
41 .7
55
33
1/2
41 .7
55
36
1/2
41 .7
55
40
1/2
41 .7
55
44
1/2
41 .7
55
49
1/2
41 .7
55
54
1/2
41 .7
55
60
3/4
115
150
Drive Sheave Alignment
Check the drive sheave alignment using the four-point method
shown in
Figure 29
. When measuring from the straight edge to
the belt, the distance at points A, B, C, and D must be equal for
correct alignment .
Figure 29: Sheave Alignment
RPM Changes
All units are provided with fixed pitch sheaves selected for the
specified operating conditions. If a new fan rpm selection is
required, field install a new sheave selection. Adjust the belt
tension as described below .
Cross Section Reference
B
C
A
FUNNEL END TO FAN
WHEEL OPENING
EQUALLY
SPACED AROUND
DIAMETER
B
A
C
D
Field Supplied Straightedge
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