Adjustable Pitch Sheaves (T.b. Woods - Model Fhp); Figure 92 - Adjustable Pitch Sheave (Fhp) - York AHU Operation And Maintenance

FORM 102.20-OM2
ISSUE DATE: 6/01/2015
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 3–8 in Installing Sheave on page
82 in this section.
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
4. Remove the belts.
5. Loosen the set screws on the adjustable flange(s)
of the sheave (Allen wrench) as shown in Figure
92 on page 85.
MOUNTING SET SCREW
ADJUSTABLE FLANGES
KEYWAY
CENTRAL
SLEEVE
STATIONARY FLANGE

FIGURE 92 - ADJUSTABLE PITCH SHEAVE (FHP)

JOHNSON CONTROLS
6. Screw the adjustable flange(s) open to expose and
loosen the mounting setscrew in the central sleeve
over the key.
7. Clean and remove any burrs from the shaft from
the sheave to end.
8. 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
7–10.
8. Alignment procedure for multiple groove adjust-
SETSCREW
able 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 tight-
ening the setscrew over the key to the proper
torque value.
12. Adjust the sheave flange(s) to the desired pitch
diameter. Each turn of the flange changes the
pitch diameter approximately 0.2 in. Six turns are
required to adjust the sheave from minimum to
LD09666
maximum for A or B belts, and seven turns for
5V belts.
SECTION 4 - SERVICE AND REPAIR
4
85