KAH Operation & Maintenance Guide
Page: 67 of 88
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12. Adjust the sheave flange(s) to the desired
pitch diameter. Each turn of the flange
changes the pitch diameter approximately
0.2”. Six turns are required to adjust the
sheave from minimum to maximum for A or B
belts, and seven turns for 5V belts.
13. Lock the adjustable flange(s) in position by
tightening the set screw(s) to the proper
torque value.
14. To prevent damage to the central sleeve
threads, the set screws MUST be over one
of the flat areas of the central sleeve. If the
flange is not properly locked, the sheave will
fail rapidly.
15. Install the belts and tighten properly.
16. Recheck the alignment and speed.
Adjusting Sheave
1. Remove the belts.
2. To adjust pitch diameter loosen setscrew(s)
on adjustable flange(s) of sheave.
3. Follow Steps 9 through 12 in Installing
Sheave in this section.
SECTION 4 - SERVICE & REPAIR
Adjustable Pitch Sheaves (T.B. Woods - Model FHP)
Tools and Material Required
•
Standard mechanic’s hand tools
•
Medium flat file
•
Torque wrench (0-250 in-lb)
•
Hex (Allen) socket set for torque wrench
•
Square and straight edge
•
Fine Emery cloth
Removing Sheave
1. Remove the belts.
2. Loosen the set screws on the adjustable flange(s) of the
sheave (Allen wrench) as shown in Figure 80 (right).
3. Screw the adjustable flange(s) open to expose and loosen
the mounting setscrew in the central sleeve over the key.
4. Clean and remove any burrs from the shaft from the sheave
to end.
5. Slide the sheave off of the shaft.
Installing Sheave
1. Loosen set screws on adjustable flange(s) of new sheave
(Allen wrench).
2. Screw the adjustable flange(s) open to expose and loosen
the mounting setscrew in the central sleeve over the keyway.
3. Inspect the shaft and key for any nicks and burrs. Remove
same and clean shaft.
4. Insert the key into the keyway.
5. Slide the new sheave onto the shaft with the mounting
setscrew over the key and toward the motor.
6. The fan and motor sheaves should be placed on their
respective shafts far enough to have the shaft exposed past
its chamfer, if possible, which will facilitate ease of alignment
later in this process.
7. Align the adjustable sheave’s stationary flange with the
respective flange of the companion sheave. On adjustable
sheaves of two or more grooves, if there is a difference of
more than 1/8” between the width of the companion sheave
and any adjustable pitch sheave, align using steps 7 through
10.
Alignment Procedure for Multiple Groove Adjustable Sheaves
9. Use a square and straight edge to align the center or
stationary flange of the adjustable sheave with the center
flange of the companion sheave.
10. Insure the shaft of the motor is parallel to the shaft of the fan.
11. Secure the adjustable sheave to the shaft by tightening the
setscrew over the key to the proper torque value.
FIGURE 80 - ADJUSTABLE PITCH SHEAVE
(FHP)
STATIONARY FLANGE
CENTRAL
SLEEVE
ADJUSTABLE FLANGES
KEYWAY
MOUNTING SET SCREW
SETSCREW
CAUTION -
Both flanges of a two-groove
sheave MUST be adjusted evenly.
