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Align Fan and Motor Sheaves
Align the fan and motor sheaves using a straightedge. The
straightedge must be long enough to span the distance
between the outside edges of the sheaves. When the sheaves
are aligned, the straightedge will touch both sheaves at points
A through D (see
Figure
66) to confirm the shaft is parallel. For
uneven width sheaves, place a string in the center groove of
both sheaves and pull tight. Adjust the sheaves and tighten the
sheave set screws to the proper torque given in
Check Multiple Belts
Tighten the belts slightly and rotate the drive several times.
On multiple belt drives, ensure the force of deflection is
approximately the same on each belt by pushing each belt in
an equal distance at a point halfway from each sheave (see
Figure
66). If this force is not the same for each belt, the motor
and fan shaft are not parallel. Realign as required. After
realignment, tighten the belts again to the standard belt
tensioning specifications. If the force is still not the same for all
belts, the belts or sheaves are worn and must be replaced.
Table 17. Set screw torque settings (inches)
Screw Size
Hex Key
1/4
1/8
5/16
5/32
3/8
3/16
7/15
7/32
1/2
1/4
5/8
5/16
#10
3/32
External Insulating Requirements
The following areas should be specifically addressed, as
applicable:
•
Supply and return water piping connections
•
Supply and return refrigerant piping connections
•
Condensate drain lines and connections
•
Outdoor-air-intake duct connections
•
Discharge duct connections
•
Special requirements for low-temperature-air systems
•
Electric duct heaters mounted on the fan discharge
64
Figure 66. Proper drive alignment
Table
17.
Square Head
Hex Head
3/8
7/16
1/2
1/2
9/16
9/16
5/8
5/8
3/4
3/4
15/16
15/16
-
-
Center line
must coincide
D
Fixed
sheave
Fixed
C
sheave
B
A
Adjustable
sheave
Torque (in.-lb.)
66-90
126-164
228-300
348-450
504-650
1290-1390
28-40
Lines must
be parallel
Straight
edge
Torque (ft.-lb.)
5.5-7.5
10.5-13.7
19.0-25.0
29.0-37.5
42.0-54.2
107.0-116.0
2.3-3.3
CLCH-SVX009L-EN
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