38
B.
BELT TENSION
When your radiator is supplied with a V-belt driven fan, the belt tension will need to be
checked frequently. Proper belt tension is necessary for normal belt and bearing life and
to provide the required radiator cooling performance.
See Section III. H. for installation of fan drive components (including V-belts) to be
installed by the customer. On remote radiators, the belts and sheaves are initially
installed and properly tensioned by Rocore.
In either case, the V-belts should be tensioned to the deflection forces as shown in
Table 4.
Table 4: Deflection force for belt tension with supergrip belts and gripnotch belts
BELT
CROSS
SECTION
SMALLEST
SHEAVE
DIAMETER
RANGE
BELT DEFLECTION FORCE – LBS
SUPERGRIP
BELTS
GRIPNOTCH
BELTS
USED
BELT
NEW
BELT
USED
BELT
NEW
BELT
B
5.8 – 8.6
6.3
9.4
8.5
12.6
C
7.0 – 9.0
9.5 – 16.0
11.5
14.1
17.0
21.0
14.7
15.9
21.8
23.5
5V
7.1 – 10.9
11.8 – 16.0
12.7
15.5
18.9
23.4
13.7
17.1
22.1
25.5
The deflection force in the above table should be measured at the midpoint of the belt
span (distance between two sheave centerlines) with a belt tension checker. For more
detailed instructions, follow the belt tension checker’s instructions.
New drives should be tensioned close to the maximum recommended deflection force.
Check the tension frequently during the first 24 to 48 hours of operation. The ideal
tension is the lowest tension at which the belts will not slip under peak load conditions.
WARNING! Over-tensioning belts shortens belt and bearing life.
WARNING! Under-tensioning belts can cause the following:
-
Premature belt wear
-
Reduced radiator cooling performance as a result of slower fan speed
-
Fan failure. Some types of fans may have critical or resonant
frequencies that must be avoided.
Use of a tachometer to check for proper fan speed can assist in checking belt tension.
Check the belt tension or fan speed regularly and re-tension if required.
CAUTION! Never apply belt dressing, as this will damage belts and cause early
failure.
