2 V-Belt Tension Method

00 ch
-9 n
71 ic
-7 alo
-2 I
27 nd
55 u
90 str
; F ia
ax l S
: 0 up
0- pl
97 y
1- LL
7- C
22
75
59
1
IMPORTANCE OF PROPER TENSIOING OF BELT DRIVES
T2e
SLACK SIDE
T2e
TIGHT SIDE
Driving
Pulley
H.P. =
T1e
T1e
2π N T
4500
OR
kW =
Driven
Pulley
NT
9550
H.P. Or kW = K N T, Where K = Constant
H.P. or kW α N T,
H.P. or kW α T, For a given drive as Revns./Min are fixed
Torque = Force x Distance.
For Belt Drives, Torque = Belt Tension x Pulley Radius
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Thus for a given set of pulleys and belts, Torque α Tension
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l:
Thus H.P. or kW transmitted will directly depend on the
Tension on the belts
1
1
00 ch
-9 n
71 ic
-7 alo
-2 I
27 nd
55 u
90 str
; F ia
ax l S
: 0 up
0- pl
97 y
1- LL
7- C
22
75
59
Belt Tension Indicator
10
20
30 40
mm
50
Deflection in mm
60 14 12 10 8 6 4
kg
2
Fenner
Deflection Force in kg
Belt Tension Indicator
applied to mid-span
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l:
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16mm deflection per metre of span
2
1
00 ch
-9 n
71 ic
-7 alo
-2 I
27 nd
55 u
90 str
; F ia
ax l S
: 0 up
0- pl
97 y
1- LL
7- C
22
75
59
As the high performance of Fenner premium Belts requires
correct tension, we recommend using the Belt Tension Indicator.
Method of Belt Tensioning
1. Measure the span length
2. Multiply the span length in metres by 16 to obtain the
deflection distance in mm.
3. Set the lower marker ring at the deflection distance required
in mm on the lower scale.
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l:
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4. Set the upper marker ring against the bottom edge of the top
tube.
3
1
00 ch
-9 n
71 ic
-7 alo
-2 I
27 nd
55 u
90 str
; F ia
ax l S
: 0 up
0- pl
97 y
1- LL
7- C
22
75
59
5. Place the belt tension indicator on top of the belt at the centre of
span, and apply a force at right angles to the belt deflecting it to
the point where the lower marker ring is level with top of the
adjacent belt.
6. Read off the force value indicated by the top edge of the upper
marker ring.
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l:
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7. Compare this force to the value shown in the table below.
4
1
00 ch
-9 n
71 ic
-7 alo
-2 I
27 nd
55 u
90 str
; F ia
ax l S
: 0 up
0- pl
97 y
1- LL
7- C
22
75
59
Belt
Section
SPZ
56
to
95
Newton
(N)
10
to
15
Kilogram
- force
(kgf)
1.0
to
1.5
SPB
SPC
Z
A
B
C
100
to
140
90
to
132
140
to
220
140
to
224
236
to
315
224
to
355
375
to
560
56
to
100
80
to
140
125
to
200
200
to
400
15
to
20
20
to
27
28
to
35
35
to
50
50
to
65
60
to
90
90
to
120
5
to
7.5
10
to
15
20
to
30
40
to
60
1.5
to
2.0
2.0
to
2.7
2.8
to
3.5
3.5
to
5.1
5.1
to
6.6
6.1
to
9.2
9.2
to
12.2
0.5
to
0.8
1.0
to
1.5
2.0
to
3.1
4.1
to
6.1
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l:
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Small
Pulley
Dia
(mm)
SPA
5
1
00 ch
-9 n
71 ic
-7 alo
-2 I
27 nd
55 u
90 str
; F ia
ax l S
: 0 up
0- pl
97 y
1- LL
7- C
22
75
59
If the measured force falls within the values given, the drive will be
satisfactory. A measured force below the lower value indicates
under- tensioning.
A new drive should be tensioned to the higher value to allow for the
normal drop in tension during the running-in period.
After the drive has been running for a few hours the tension should
be checked and re-adjusted to higher the value.
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l:
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Note: For single belt drives a straight edge should be placed across
the two pulleys to act as a datum for measuring the amount of
deflection.
6

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