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SMALLEST SHEAVE
BELT STYLE
DIAMETER RANGE
3.0 - 3.6
A, AX
3.8 - 4.8
5.0 - 7.0
3.4 - 4.2
B, BX
4.4 - 5.6
5.8 - 8.6
7.0 - 9.0
C, CX
9.5 - 16.0
12.0 - 16.0
D
18.0 - 20.0
2.2 - 2.4
3V, 3VX
2.65 - 3.65
4.12 - 6.90
4.4 - 6.7
5V, 5VX
7.1 - 10.9
11.8 - 16.0
12.5 - 17.0
8V
18.0 - 22.4
EXAMPLE:
Given:
Belt Span
Belt Cross-Section A, Super Belt
Small Sheave PD
Small Sheave RPM:
Belt Condition:
Deflection =
Solution:
a. From Table 32, find that deflection force for a new
type A, super belt with 5-in. small sheave PD is 8 lb.
a. Deflection =
/
16
64
=
/
1
4
TENSION MEASUREMENT PROCEDURE
1.
Measure the belt span (see Fig. 56).
2.
Position bottom of the large o-ring on the span scale at the
measured belt span.
3.
Set the small o-ring on the deflection force scale to zero.
4.
Place the tension checker squarely on one belt at the center of
the belt span. Apply a force on the plunger and perpendicular
to the belt span until the bottom of the large o-ring is even
with the top of the adjacent (next) belt or with the bottom of a
Table 32 — Fan Belt Tension Data
SHEAVE DIAMETER (in.)
DEFLECTION FORCE (lb)
RPM RANGE
1000-2500
2501-4000
1000-2500
2501-4000
1000-2500
2501-4000
860-2500
2501-4000
860-2500
2501-4000
860-2500
2501-4000
500-1740
1741-3000
500-1740
1741-3000
200-850
851-1500
200-850
851-1500
1000-2500
2501-4000
1000-2500
2501-4000
1000-2500
2501-4000
500-1749
1750-3000
3001-4000
500-1749
1750-3000
3001-4000
500-1749
1750-3000
3001-4000
200-850
851-1500
200-850
851-1500
16 in.
5 in.
1530
New
Belt Span/64
or
in.
BELT DEFLECTION FORCE
SUPER GRIP BELTS AND UNNOTCHED
GRIPBANDS
USED BELT
NEW BELT
3.7
5.5
2.8
4.2
4.5
6.8
3.8
5.7
5.4
8.0
4.7
7.0
—
—
—
—
5.3
7.9
4.5
6.7
6.3
9.4
6.0
8.9
11.5
17.0
9.4
13.8
14.1
21.0
12.5
18.5
24.9
37.0
21.2
31.3
30.4
45.2
25.6
38.0
—
—
—
—
3.6
5.1
3.0
4.4
4.9
7.3
4.4
6.6
—
—
—
—
—
—
12.7
18.9
11.2
16.7
15.5
23.4
14.6
21.8
33.0
49.3
26.8
39.9
39.6
59.2
35.3
52.7
straight edge laid across the outside diameters of the v-belt
sheaves.
5.
Remove the tension checker and read the force applied from
the bottom of the small o-ring on the deflection force scale.
6.
Compare the force you have applied with the values given in
Table 32. The force should be between the "Used Belt" and
"New Belt" values shown. The maximum value is shown for
"New Belt" and new belts should be tensioned at this value to
allow for expected tension loss. "New Belt" tensions should
be used at initial installation and after job start or 1 to 3 min-
utes of operation. Used belts should be maintained at the
value as indicated in the chart. "Used Belt" tensions should
be used for the 8-hour and subsequent checks. If the belt span
was measured in centimeters, then use the kilograms of force
values for comparison.
NOTE: The ratio of deflection to belt span is 1:64 in either units of
measurements.
7.
Whenever possible, jog start for a few revolutions or prefera-
bly run drive for approximately 1 to 3 minutes and then re-
tension in accordance with Steps 1-6. Running the drive for a
few revolutions or minutes will help seat the belt(s) in the
groove(s). This relatively early re-tensioning may reduce or
minimize the amount of re-tensioning required in the first 24
hours of drive service.
119
GRIP NOTCH BELTS AND NOTCHED
GRIPBANDS
USED BELT
NEW BELT
4.1
6.1
3.4
5.0
5.0
7.4
4.3
6.4
5.7
8.4
5.1
7.6
4.9
7.2
4.2
6.2
7.1
10.5
6.1
9.1
8.5
12.6
7.3
10.9
14.7
21.8
11.9
17.5
15.9
23.5
14.6
21.6
—
—
—
—
—
—
—
—
3.3
4.9
2.9
4.3
4.2
6.2
3.8
5.6
5.3
7.9
4.9
7.3
10.2
15.2
8.8
13.2
5.6
8.5
14.8
22.1
13.7
20.1
17.1
25.5
16.8
25.0
—
—
—
—
—
—
—
—
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