Interroll Drum motor series i, S, S/A, D
Assembly and installation
82
Version 4.1 (06/2015) en-US 
Translation of original instruction manual
 
The belt elongation can very easily be determined using a measuring tape.
4
  Mark the untensioned belt at two points in the center where the outer diameter of the drum 
motor and the idler pulley are the largest due to the camber.
4
  Measure the distance between the two markings parallel to the belt edge (Be0). The greater 
the distance between the two markings, the more precise the belt elongation can be 
measured.
4
  Tension and align the belt.
4  Measure the distance between the markings (Be) again.
    The belt elongation increases the distance.
Be [mm]
BeO [mm]
Measuring the belt elongation
 
The belt elongation can be calculated in % with the determined measure of the belt elongation.
e%
=
B
e
100%
B
Formula for calculating the belt elongation in %
Calculating the belt elongation requires the following values:
  •  Belt width in mm (BW)
  •  Static force per mm belt width with 1 % elongation in N/mm (k1 %). The value is recorded 
on the data sheet for the belt or can be obtained from the belt supplier.
E
[static]
=
BW
k1%
B
e%
Formula for calculating the static belt tensioning force in N
Measuring the 
belt elongation
Calculating the 
belt elongation