Installation manual

ManualsBrandsMcQuay ManualsAir HandlersRAH 077C

Page 78 IM-487

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 "D".

3. Loosen but do not remove capscrews "E".

4. Remove key "F". This key projects a small amount to pro-

vide a grip for removing.

5. Adjust the pitch diameter by opening or closing the mov-

able flange by half or full turns. Note that two-groove

sheaves are supplied with both grooves set at the same

pitch diameter. Both movable flanges must be moved

the same number of turns to verify the same pitch

diameter for satisfactory operation. Do not open

sheaves more than five turns for "A" belts or six turns

for "B" belts.

6. Replace key "F".

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.

9. Be sure that all keys are in place and that all setscrews and

all capscrews are tight before starting the drive. Check

and retighten all screws and retension the belts after

approximately 24 hours of operation.

MVP Variable Pitch Sheaves

Adjusting:

1. Slack off 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 both locking screws "A" in outer locking ring, but

do not remove them from the sheave. There is a gap of

approximately .2" (1 mm) between the inner and outer

locking rings. This gap must be maintained for satisfac-

tory locking of the sheave.

If locking screws "A" are removed by accident and the

gap is lost, screw the outer locking ring down until it

touches the inner locking ring. Then back off the outer

ring 1/2 to 3/4 turn until the inner and outer ring screw

holes are lined up. Reinsert locking screws "A", but do not

tighten them until after adjustment is made.

3. Adjust the sheave to the desired pitch diameter by turning

the outer locking ring with a spanner wrench. Any pitch

diameter can be obtained within the sheave range. One

complete turn of the outer locking ring will result in a

0.233" (6 mm) change in pitch diameter.] Do not open

"A-B" sheaves more than 43/4 turns for "A" belts or 6

turns for "B" belts. Do not open "C" sheaves more

than 9-1/2 turns.

4. Tighten both locking screws "A" in the outer locking ring.

5. 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.

Caution:Do not loosen any screws other than the two locking

screws "A" in the outer locking ring. These screws must be

tightened securely before the drive is operated.

Figure 76. LVP variable pitch sleeves

S e c t i o n A - A S e c t i o n A - A