Mounting And Adjusting Motor Sheaves - Daikin RDT-135c Installation And Maintenance Manual

Check, Test, and Start Procedures: Mounting and Adjusting Motor Sheaves

Mounting and Adjusting Motor Sheaves

Figure 109. VM and VP variable pitch sheaves
VM and VP Variable Pitch Sheaves
Mounting:
1 Mount all sheaves on the motor shaft with setscrew A
toward the motor (see Figure 109 on page 106).
2 Be sure both the driving and driven sheaves are in
alignment and that the shafts are parallel.
Fit internal key D between sheave and shaft and lock
3
setscrew A securely in place.
Adjusting:
Slack off all belt tension by moving the motor toward the
1
driven shaft until the belts are free from the grooves. For
easiest adjustment, remove the belts.
Loosen setscrews B and C in the moving parts of the
2
sheave and pull out external key E (see Figure 109). This
key projects a small amount to provide a grip for removing.
Adjust the sheave pitch diameter for the desired fan speed
3
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 both grooves have the same pitch diameter.
Replace external key E and securely tighten setscrews B
4
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.
106
Be sure that all keys are in place and that all setscrews are
6
tight before starting the drive. Check the setscrews and belt
tension after 24 hours of service.
LVP Variable Pitch Sheaves
Mounting:
For single-groove sheaves, slide the sheave onto the motor
1
shaft so that the side of the sheave with setscrew A is next
to the motor (see Figure 110 on page 107). For two-groove
sheaves, slide the sheave onto the motor shaft so that the
side of the sheave with setscrew A is away from the motor
(see Figure 110 on page 107).
2 To remove the flange and locking rings:
a Loosen setscrews D.
Loosen but do not remove capscrews E.
b
c Remove key F. This key projects a small amount to
provide a grip for removing.
d Rotate the flange counterclockwise until it disengages
the threads on the shaft barrel.
Be sure that the driving and driven sheaves are in alignment
3
and the shafts are parallel. When aligning two-groove
sheaves, allow room between the sheave and motor to get
to capscrews E.
4 Insert key C between the sheave and the shaft and tighten
setscrew A securely.
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.
Loosen setscrews D.
2
Loosen but do not remove capscrews E.
3
Remove key F. This key projects a small amount to provide
4
a grip for removing.
Adjust the pitch diameter by opening or closing the
5
movable flange by half or full turns. Note that two-groove
sheaves are supplied with both grooves set at the same
pitch diameter. To ensure the same pitch diameter for
satisfactory operation, move both movable flanges the
same number of turns. Do not open sheaves more than
five turns for A belts or six turns for B belts.
Replace key F.
6
7 Tighten setscrews D and capscrews E.
8 Put on the 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
Before starting the drive, make sure that all keys are in
9
place and all setscrews and all capscrews are tight. Check
and retighten all screws and retension the belts after
approximately 24 hours of operation.
IM 738-2