PT SARANA TEKNIK
belts are Precision Built to ensure inherent
length stability and matching during storage and on the drive.
Over many years, the principle of "one-shot" tensioning has
been verified by successful drives the world over.
Install the belts to be a snug fit around the
Spin the pulleys 3-4 revolutions to bed belts into
the pulley grooves.
(Note: if done manually, beware of finger entrap-
ment between belts and pulleys)
Tension the belts to the 1.25x setting forces
from the table.
Run the drive under load for 15-20 minutes.
Stop the drive, check tension & reset to the basic
value (standard V and wedge belts) if necessary.
CRE PLUS & Quattro PLUS belts should be reset
to the 1.25x value.
With a drive that is properly designed for the application
there should be no need for further attention during the
life of the belts.
For short centre distance drives where the deflection of the
belt is too small to measure accurately it is recommended
that both deflection and setting force be doubled.
Method of belt tensioning using Fenner Belt
Calculate the deflection in mm on a basis of 16mm
per metre of centre distance. Centre distance (metres)
x 16 = deflection (mm).
Set the lower marker ring at the deflection distance
required in mm on the lower scale.
Set the upper marker ring against the bottom edge
of the top tube.
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 the top of an adjacent belt.
Read off the setting force value indicated by the top
edge of the upper marker ring.
Compare this force to the kgf value shown in the
If a Fenner Belt Tension Indicator is not available, a
spring balance and rule will suffice.
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.
If the measured force falls within the values given,
the drive should be satisfactory. A measured force
below the basic value indicates under-tensioning.
A new drive should be tensioned to the 1.25x value
to allow for the normal drop in tension during the
After the drive has been running for 15–20 minutes,
under load the tension should be checked and re-
adjusted, if necessary.
Small radial cracks on belt side and base
Generally caused by slippage due to insufficient belt
tension, but excessive heat and/or chemical fumes
can also cause the same problem.
Belt swelling or softening
Caused by excessive contamination by oil, certain cutting
fluids, water or rubber solvent.
Whip during running
Often caused by incorrect tensioning, particularly
on long centre drives. If a slightly higher (or lower)
tension does not cure the problem there may be
a critical vibration frequency in the system which
requires re-design or use of banded belts. Consult
your local Authorised Distributor Technical Services.
Pulley groove wear can cause rapid belt failure.
Check grooves for