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KAH Operation & Maintenance Guide
Page: 66 of 88
SECTION 4 - SERVICE & REPAIR
Adjustable Pitch Sheaves (T.B. Woods - Model JVS)
Tools and Material Required
•
Standard mechanic’s hand tools
•
Medium flat file
•
Torque wrenches (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 both clamp screws with an Allen wrench as shown in
Figure 79 (right).
3. Clean and remove any burrs from the shaft from the sheave
to the end.
4. Slide sheave off shaft. If tight, insert screwdriver into slit in
central sleeve.
Installing Sheave
1. Loosen the clamp screws on the new sheave.
2. Slide the JVS sheave onto the shaft. Place the fan and motor
sheaves on their respective shafts far enough to have the
shaft exposed past its chamfer, which will facilitate proper
alignment later in the process.
3. The central sleeve of this sheave is split at one end only.
Install this end first as the split allows the sheave assembly
to be secured to the shaft.
4. Adjust the sheave to the approximate pitch diameter desired.
One turn of the adjusting screw will vary the pitch diameter
0.2”. Seven turns are required to adjust the sheave from the
minimum to the maximum pitch diameter.
5. Put slight finger pressure on the face of the adjustable flanges
near the split (180 ° from the adjusting screw) to permit free
and equal movement of the flanges during pitch adjustments.
Otherwise, tipping and binding may occur.
6. Align the sheave with the companion sheave.
7. If there is a difference of more than 1/8” between the width
of the companion sheave and any adjustable pitch sheave,
align them, using Steps 5-6.
Alignment Procedure for 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.
FIGURE 79 - ADJUSTABLE PITCH SHEAVE
(JVS)
STATIONARY FLANGE
CLAMP SCREW
SLIP
CENTRAL
SLEEVE
ADJUSTABLE FLANGES
ADJUSTING SCREW
KEYWAY
11. Tighten the two clamp screws to the following
torque values:
»
JVS Model: 130-160 in-lb. or 13 ft-lb
»
All other JVS Models: 325 in-lb or 27 ft-lb
12. Install the belts and tighten properly.
13. Recheck the alignment and speed.
Adjusting Sheave
1. To adjust the pitch diameter, loosen both
clamp screws.
2. Remove the belts.
3. Follow Steps 3 through 8 in Installing Sheave
in this section.
NOTE -
Be careful not to grasp flanges
in such a manner as to cock them while
tightening the clamp screws.
