Product manual

42 McQuay IM 782-4
Service and Maintenance
2 Verify that both driving and driven sheaves are in
alignment and that shafts are parallel.
3 Fit internal key D between sheave and shaft and lock
setscrew
A securely in place.
Adjusting:
1 Loosen setscrews B and C in moving parts of sheave and
pull out external key
E. (This key projects a small
amount to provide a grip for removing.)
2 Adjust sheave pitch diameter for desired speed by
opening 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.
3 Replace external key E and securely tighten setscrews B
over key and setscrews
C into keyway in fixed half of the
sheave.
4 Put on belts and adjust belt tension.
Do not force belts over grooves. See “Fan Drive Belt
Adjustment” on page 28.
5 Make future adjustments by loosening the belt tension
and increasing or decreasing the pitch diameter of the
sheave by half or full turns as required. Readjust belt
tension before starting drive.
6 Adjust both halves of two-groove sheaves the same
number of turns from closed position to provide the same
pitch diameter.
7 Verify that all keys are in place and that all setscrews are
tight before starting drive. Check setscrews and belt
tension after 24 hours service.
Figure 39: VP Type Sheave Adjustment
LVP Variable Speed Sheaves
Mounting:
1
Slide sheave on motor shaft so that the side of the sheave
with setscrew
A is next to the motor, when setscrew A is
in the hub or barrel of the sheave.
2 When setscrew A is at an angle in the center flange B,
mount it away from the motor so the outer locking ring
and flange can be removed to get to the setscrew.
3 To remove the flange and locking ring:
a Loosen setscrews D.
b Loosen but do not remove capscrews E.
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 sheave barrel.
4 Verify that the driving and driven sheaves are in
alignment and the shafts are parallel. When aligning two-
groove sheaves, allow room between the sheave and
motor to get to capscrews
E.
5 Insert key C between the sheave and the shaft and tighten
setscrew
A securely.
6 If flange and locking ring have been removed, when
replacing them make sure that the inner and outer flanges
are open from the closed position by the same amount as
the other flange. Determine this by accurately measuring
the top width of the grooves.
Two groove
C
A
B
B
D
E
C
A
B
E
D
C
Single groove
Key E projects
to provide a grip
for removal.
Note: Do not operate sheave with flange
projecting beyond the hub end.