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CLCH-SVX009A-EN
53
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 46
) 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
Table 16
.
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 46
). 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.
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
Figure 46.
Proper drive alignment
D
Fixed
Sheave
C
B
A
Adjustable
Sheave
Straight
Edge
Lines must
be parallel
Center line
must coincide
Fixed
Sheave
Table 16. Set screw torque settings (inches)
Screw Size
Hex Key
Square Head
Hex Head
Torque (in.-lb.)
Torque (ft.-lb.)
1/4
1/8
3/8
7/16
66-90
5.5-7.5
5/16
5/32
1/2
1/2
126-164
10.5-13.7
3/8
3/16
9/16
9/16
228-300
19.0-25.0
7/15
7/32
5/8
5/8
348-450
29.0-37.5
1/2
1/4
3/4
3/4
504-650
42.0-54.2
5/8
5/16
15/16
15/16
1290-1390
107.0-116.0
#10
3/32
-
-
28-40
2.3-3.3
