Interroll Drum motor series i, S, S/A, D
Troubleshooting
100
Version 4.1 (06/2015) en-US 
Translation of original instruction manual
Fault Possible cause Remedy
Drum motor runs faster than 
specified.
Wrong motor speed ordered/
delivered
Check drum motor specifications and tolerances.
Replace drum motor or contact local Interroll dealer.
Wrong settings at frequency 
inverter
Check whether the frequency inverter settings meet the 
specifications of the drum motor and change them if necessary.
Use of a 50-Hz motor in a 60-
Hz supply system
Check whether motor specifications and tolerances correspond 
to the supply voltage/frequency.
Replace drum motor or contact local Interroll dealer.
Thickness of rubber coating 
increased the belt speed 
beyond the rated speed of the 
motor
Measure thickness of rubber coating and check whether this 
value was considered and calculated in the selection of the 
drum motor speed.
Reduce thickness of rubber coating or install a frequency 
inverter or install new drum motor with lower speed.
Motor winding: one phase 
failed
Failure/overload of winding 
insulation
Check continuity, current and resistance of phase winding.
Replace drum motor or contact local Interroll dealer.
Motor winding: two phases 
failed
Power failure at one phase 
which leads to overload at the 
other two phases / separating 
failure
Check power supply to all phases. Check continuity, current 
and resistance of phase winding.
Replace drum motor or contact local Interroll dealer.
Motor winding: all three 
phases failed
Motor overload / wrong 
current connection
Check whether the correct supply voltage is present.
Check continuity, current and resistance of phase winding.
Replace drum motor or contact local Interroll dealer.