19
6. Maintenance
Method of Belt Tensioning using
Fenner Belt Tension Indicator.
1. Calculate the deflection distance in
mm, on a basis of 16 mm per meter, of
centre distance (see Figure 20).
Centre distance (m) x 16 = deflection
(mm).
2. Set the lower marker ring at the
deflection distance required in mm on
the lower scale.
3. Set the upper marker ring against the
bottom edge of the top tube.
4. Place the belt tension indicator on the
top of the belt at the centre of the span.
Apply a force at right angles to the belt,
deflecting it to the point where the
lower marker ring is level with the top of
the adjacent belt.*
5. Read off the force value indicated by
the top edge of the upper marker ring.
6. Compare this force to the kgf value
shown in Table 2.
*NOTE:
For a single belt drive, a straight edge
should be placed across the two pulleys
to act as a datum for measuring the
amount of deflection.
Fenner is a registered trademark of J H Fenner & Co Ltd.
Taper Lock and P B (Precision Built) are registered trademarks of F P T Group.
Table 2 – Tensioning Forces (Force required to deflect belt 16 mm per metre of span)
Belt Section
SPZ
SPA
SPB
SPC
Z
A
B
C
Small Pull Diameter (mm)
56
100
80
140
112
236
224
375
56
80
125
200
to
to
to
to
to
to
to
to
to
to
to
to
95
130
132
200
224
315
355
560
100
140
200
400
Newton (N)
13
20
25
35
45
65
85
115
5
10
20
40
to
to
to
to
to
to
to
to
to
to
to
to
20
25
35
45
65
85
115
150
7.5
15
30
60
Kilogram-Force (kgf)
1-3
2-0
2-5
3-6
4-6
6-6
8-7
11-7
0-5
1-0
2-0
4-1
to
to
to
to
to
to
to
to
to
to
to
to
2-0
2-5
3-6
4-6
6-6
8-7
11-7
15-3
0-8
1-5
3-1
6-1
Deflection in mm
Deflection Force in kg
Reproduced with permission of F P T Group.
If the measurement force falls within the
values given, the drive should be
satisfactory. A measured force below the
lower value indicates undertensioning.
A new drive should be tensioned to a
higher value to allow for the normal drop
in tension during the running-in period.
After the drive has been running for 30
minutes, the tension should be checked
and readjusted to the higher value, if
necessary.
Figure 20
Fenner is a registered trademark of J H
Fenner & Co Ltd.
Taper Lock and P B (Precision Built) are
registered trademarks of F P T Group.
Reproduced with permission of F P T
Group.
Figure 20 Notes:
1. 1/2 Centres
2. Force
3. 16 mm deflection / 1 m of centre distance
4. Centre Distance
Damage to the motor and fan bearings
can result from the belt being
overtensioned.
In the event of the belt adjustment
being too slack, undue wear and
slippage may result.
1
2
3
4
IMPORTANT
CLCH-SVX05A-GB
