13
English
9 - Preliminary Checks Before Start-up (continued)
9.1 - Adjustable pulley adjustment
Mounting
1. The pulley must be mounted on the motor shaft with the
aid of the set screws "A".
2. Be sure that both driving and driven pulleys are in
alignment and that shafts are parallel (see paragraph
"Belt alignment").
3. Securely tighten the set screw "A" on the keyway of the
motor shaft.
Adjusting
1. Loosen the set screw "B" located in the pulley moving
sheave.
2. Adjust the sheave pitch diameter for a desired rotational
speed by opening the moving sheave by half turns or
full turns from the closed position.
Fan rotational
speed
(rpm)
Motor rotational
speed
(rpm)
=
x
Motor pulley diameter
Fan pulley diameter
3. Securely tighten the set screw "B" on the flat surface of
the pulley fixed sheave.
4. Put on the belt and adjust its tension.
Do not force
the belt on the pulley sheaves
(see paragraph "Belt
tensioning").
5. The future adjustments should be performed by
loosening the belt tension and by increasing or
decreasing the pulley pitch diameter by half turns or
full turns as required. Re-adjust the belt tension before
starting the motor.
6. Make certain that all parts are in place and that all set
screws are tight before starting the motor. Check set
screws and belt tension after a 24 hour operation.
Remark :
The authorized maximum opening of the pulley
is 3.5 turns from the completely closed position. If this
maximum opening is not followed, there is a risk of early
breaking of the belt.
Screw "A"
Screw "B"
Screw "B"
Flat
surface
Flat
surface
Moving
sheave
Fixed
sheave
