Aligning Sheaves; Using A Straightedge; Using A String - Pace PAI Installation And Assembly Manual

PACE │ Installation & Assembly Manual
Thrust Restraint Replacement
Supply fan is attached to bulkhead (or bulkhead clip),
one thrust restraint on each side near top of fan.
1. Remove any existing thrust restraints.
2. If fan wall does not support thrust or brackets, in-
stall additional support from floor to roof and tie in
at top, bottom, and about 4-foot intervals.
3. If fan structure angle is not present or does not
line up, adjust thrust restraint mounting brackets
(or clips) furnished with thrust restraints. Attach to
each side of fan housing nearest top and toward
discharge.
4. Lock two nuts together on one end of threaded
rod.
5. Finally, add first flat steel washer, first flat rubber
washer, first steel cup retainer, spring, second
steel cup retainer, second flat rubber washer and
second flat steel washer.
6. Slide threaded rod through thrust restraint mount-
ing bracket on fan (or clip) toward bulkhead (or
bulkhead clip).
7. Add third flat steel washer and two nuts that lock
together in a later step.
The hardware in the preceding steps
goes to the fan end of threaded rod.
8. Next add one nut and one flat steel washer, and
slide threaded rod through bulkhead (or bulkhead
clip).
9. Add flat steel washer and one nut on the other
side of bulkhead (or bulkhead clip).
10. Push threaded rod through bulkhead (or bulkhead
clip) until spring parts are against thrust restraint
mounting bracket on fan (or clip).
11. Tighten nuts on both sides of bulkhead (or bulk-
head clip).
Thrust Restraint Adjustment
After installing thrust restraint, adjust as follows:
1. Ensure nuts are tight on both sides of bulkhead or
bulkhead clip.
Issue Date: 07/03/2018
SECTION 3 - HANDLING, STORAGE, AND INSTALLATION
2. Adjust third flat steel washer and second set of
double nuts hand-tight against thrust restraint
mounting bracket on fan.
3. Turn second set of double nuts four full turns to-
ward spring and lock in place.
4. Repeat this process for each thrust restraint.

ALIGNING SHEAVES

An incorrectly aligned sheave can sub-
stantially shorten belt life or overload
blower and motor bearings, shortening
their life expectancy. A belt tensioned
too tightly can overload the motor elec-
trically, causing nuisance tripping of the
motor overloads and/or motor failure
and/or shaft failure.
Sheave alignment and parallelism of shafts is very
important. Proper alignment helps equalize the load
across the entire belt width, thereby reducing wear and
extending belt life. Figure 99 on page 63 shows how
to align a synchronous drive properly using a straight-
edge or shows how to use a piece of string as shown
in Figure 100 on page 63.
After aligning the sheaves, check the rigidity of the
supporting framework. Shafts should be well support-
ed to prevent distortion and a resulting change in the
center distance under load. Do not use spring-loaded
or weighted idlers.

Using a Straightedge

Place a straightedge against the outer edge of the
sheaves. Figure 99 on page 63 shows the four points
where the straight edge should touch the sheaves. The
straight edge should cross the sheaves at the widest
possible part of the sheave.

Using a String

Tie a string around either shaft and pull it around and
across the outer edge of both sheaves as shown in
Figure 100 on page 63 shows how the string should
touch four points when the drive is properly aligned.
If alignment is different than described, refer to Belt
Replacement Tensioning and Sheave Alignment for
Top Mount on page 63 later in this section.
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Form PA102.20-N1