11
If no measurement results are displayed despite careful preparations, this may be due to
one of the following two reasons:
1. The drive belt oscillates below the minimum measurement limit of 10 Hz.
Remedy
Tighten the belt or, if the strand length is very long and open, support the belt in order
to shorten the strand length. Enter the new belt length before repeating measurement.
2. Either no or low measurement values are displayed despite the drive belt being
correctly tensioned.
Remedy
It may be the case that the light from the measuring probe is not sufficiently reflected.
To improve reflection, affix a piece of light-colored adhesive tape to the belt or slightly
moisten the belt at the measuring point.
3.5.3 Measurement Errors
In case you have no data from the machine producer about the set point of the strand
force, you can calculate the approximate strand force with the following formula.
Where:
P
= motor power (kW)
z
= number of belts
v
= belt speed = D x n/19100
D
= effective diameter of the small wheel (mm)
n
= speed of the small wheel (rpm)
m x v
2
= centrifugal force (relevant for speed
> 800 rpm
)
m
= weight of one belt (kg/m), as specified in the table
Besides the best strand force “F” consider the permissible axial load
of the bearings: AXIAL LOAD F
A
= 2 x strand force
3.6 Calculation of the Strand Force Set Point in Newtons for V-Belts
540 x P x 1,3
z
x
v
F =
+ m x v
2
