3
ACSC IO&M
B51002-002
shown in the table. When the pulleys
are not the same width, the allowable
gap must be adjusted by half of the dif-
ference in width.
Figure 3
illustrates
using a carpenter’s square to adjust
the position of the motor pulley until
the belt is parallel to the longer leg of
the square.
Operation
Pre-Start Checks
1. Lock out all the primary and secondary power sources.
2. Inspect and tighten fasteners and setscrews, particularly
fan mounting and bearing fasteners Refer to
Torque
chart.
3. Inspect belt tension and pulley alignment. Refer to
Belt and
Pulley Installation
.
4. Inspect motor wiring. Refer to
Wiring Installation
.
5. Ensure belt touches only the pulleys.
6. Rotate the wheel to ensure it rotates freely.
7. Ensure fan and ductwork are clean and free of debris.
8. Close and secure all access doors.
9. Restore power to fan.
Start-Up
Turn on the fan. In variable speed units, set fan to its low-
est speed and inspect for the following:
• Direction of rotation
• Excessive vibration
• Unusual noise
• Bearing noise
• Improper belt alignment or tension (listen for squealing)
• Improper motor amperage or voltage
NOTICE! If a problem is discovered, immediately shut
off the fan. Lock out all electrical power and check for
the cause of the trouble. Refer to Troubleshooting.
Inspection
Inspection of the fan should be conducted at the first
30
minute
,
8 hour
and
24 hour
intervals of satisfactory op-
eration. During the inspections, stop the fan and inspect
as per the
Conditions Chart
.
30 Minute Interval
Inspect bolts, setscrews and motor mounting bolts. Ad-
just and tighten as necessary.
8 Hour Interval
Inspect belt alignment and tension. Adjust and tighten
as necessary.
24 Hour Interval
Inspect belt tension. Adjust and tighten as necessary.
Recommended Torque for Setscrews/Bolts (IN-LB)
Setscrews
Hold Down Bolts
Size
Key Hex
Across
Flats
Recommended
Torque
Size
Recommended
Torque
Min.
Max.
#8
5/64”
15
21
3/8”-16
324
#10
3/32”
27
33
1/2”-13
780
1/4
1/8”
70
80
5/8”-11
1440
5/16
5/32”
140
160
3/4”-10
2400
3/8
3/16”
250
290
7/8”-9
1920
7/16
7/32”
355
405
1”-8
2700
1/2
1/4”
560
640
1-1/8”-7
4200
5/8
5/16”
1120
1280
1-1/4”-7
6000
3/4
3/8”
1680
1920
-
-
7/8
1/2”
4200
4800
-
-
1
9/16”
5600
6400
-
-
• Inspect bolts and setscrews for tightness. Tighten as
necessary. Refer to
Recommended Torque
chart.
• Inspect belt wear and alignment. Replace worn belts
with new belts and adjust alignment as needed. Refer to
Belt and Pulley Installation
.
• Bearings should be inspected as recommended in the
Conditions Chart
.
• Inspect for cleanliness. Clean exterior surfaces only.
Removing dust and grease on motor housing assures
proper motor cooling.
Belt and Pulley Installation
Belt tension is determined by the sound the belts make
when the fan is first started. Belts will produce a loud
squeal which dissipates after the fan is operating at full
capacity. If the belt tension is too tight or too loose, lost ef-
ficiency and possible damage can occur.
Do not change the pulley pitch diameter to change
tension. This will result in a different fan speed.
1. Loosen motor plate adjustment bolts and move motor
in order that the belts can easily slip into the grooves
on the pulleys. Never pry, roll or force the belts over
the rim of the pulley.
2. Slide the motor plate back until proper tension is
reached. For proper tension, a deflection of approxi
-
mately 1/4” per foot of center distance should be ob-
tained by firmly pressing the belt. Refer to
Figure 1
.
3. Lock the motor plate adjustment bolts in place.
4. Ensure pulleys are properly aligned. Refer to
Figure 2
.
Tolerance
Center
Distance
Max.
Gap
Up through 12” 1/16”
12” through 48” 1/8”
Over 48”
1/4”
Figure 2
OFFSET
ANGULAR
OFFSET/ANGULAR
A
W
X
Y
Z
B
CENTER
DISTANCE
(CD)
GAP
GAP
Pulley Alignment
Pulley alignment is adjusted by loosening the motor pulley
setscrew and by moving the motor pulley on the motor shaft.
Figure 2
indicates where to measure the allowable gap
for the drive alignment tolerance. All contact points (indi-
cated by WXYZ) are to have a gap less than the tolerance
1 foot
1/4 inch
Figure 1