X90 mobile modules
262
X90 mobile system User's manual V 1.20 - Translation of the original manual
Belt damage
Belts often cause various problems during operation. A belt can be damaged if the tension is too low or too high
or if the belt is incorrectly aligned. If the damaged belt part rolls over the pulley, this causes impacts that can be
measured.
Flat belts and V-belts
With flat belts and V-belts, torque is transferred between the belt and the pulley through the contact surface. Belt
drives are not very sensitive with regard to alignment but nevertheless lead to vibration development and above
all to increased wear and energy consumption if the deviation is too high.
Failure mode
Frequency in raw
signal spectrum
Frequency in en-
velope spectrum
Comment
Defective belt
1 x fr, 2 x fr, 3 x fr ...
1 x fn1, 1 x fn2,
1 x fr
Belt frequencies usually occur in both spectra.
fr
... Belt speed
fn1
... Nominal speed of shaft 1
fn2
... Nominal speed of shaft 2
Poorly aligned or incorrectly tensioned belts can also cause severe stress on the bearing points. The increased
vibration also causes heavier wear on belts and pulleys.
The vibrations are clearly identifiable at the bearing points of the individual shafts.
Failure mode
Frequency in raw
signal spectrum
Frequency in en-
velope spectrum
Comment
Misalignment of belt
1 x fn, 2 x fn
1 x fr
1 x fn
If the belts strike against the pulley laterally, impacts can also
occur with speed and belt frequency.
fn
... Nominal speed
fr
... Belt speed
