MVA 02 rev 5 - December 2017
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8.4
Adjusting drive belt tension and cleaning belts
A simplified method for setting the correct tension of V-belts is as follows: Chart 8-5 can be used to obtain
the value P of the load for each belt for the profile type and the diameter of the smaller pulley. The value L
can also be obtained from the same chart.
Use this formula:
100
LxI
L
e
to calculate the value L
e
,
where:
L
e
= deflection [in mm] of the section at the centre point of distance I between pulley centres
L= deflection for distance between centres of 100 mm
I = distance between centres [in mm]
Applying load P perpendicularly to the section (Fig. 8-3) the transmission must be tightened until the
calculated deflection L
e
is reached.
Fig. 8-3 Checking drive belt tension
Profile
Load on belt P
[N]
Diameter of smaller pulley d
[mm]
Deflection for distance
between centres of 100 mm L
SPZ
25
from 63 to 71
from 75 to 90
from 95 to 125
over 125
2.45
2.20
2.05
1.90
SPA
50
from 100 to 140
from 150 to 200
over 200
2.75
2.55
2.45
SPB
75
from 160 to 224
from 236 to 355
over 355
2.55
2.22
2.10
SPC
125
from 224 to 250
from 265 to 355
from 400 to 560
over 560
2.55
2.20
2.00
1.90
Chart 8-5 Setting drive belt tension: test load and deflection
L
e
I
I/2
