Daikin RoofPak RPS Series Installation And Maintenance Manual page 103

VM and VP Variable Pitch Sheaves
Mounting:
1. Mount all sheaves on the motor shaft with setscrew A
toward the motor (see
2. Be sure both the driving and driven sheaves are in
alignment and that the shafts are parallel.
3. Fit internal key D between sheave and shaft and lock
setscrew A securely in place.
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Figure 117).
Check, Test, and Start Procedures
Adjusting:
1. Slack off all belt tension by moving the motor toward the
driven shaft until the belts are free from the grooves. For
easiest adjustment, remove the belts.
2. Loosen setscrews B and C in the moving parts of the
sheave and pull out external key E (see
This key projects a small amount to provide a grip for
removing.
3. Adjust the sheave pitch diameter for the desired fan
speed by opening the moving parts by half or full turns
from closed position. Do not open more than five full
turns for A belts or six full turns for B belts . Adjust
both halves of two-groove sheaves by the same number
of turns from closed to ensure that both grooves have the
same pitch diameter.
4. Replace external key E and securely tighten setscrews B
over the key. Tighten setscrews C into the keyway in the
fixed half of the sheave.
5. Put on belts and adjust the belt tension. Do not force
belts over grooves . Loosen the belts by adjusting the
motor base closer to the fan shaft.
6. Be sure that all keys are in place and that all setscrews
are tight before starting the drive. Check the setscrews
and belt tension after 24 hours of service.
Figure 117: VM and VP Variable Pitch Sheaves
103 IM 926-3 • ROOFPAK APPLIED SYSTEMS
Figure 117).