Correlation between
Belt Natural Frequencies and Vibration Spectra
Lin Liu, Suri Ganeriwala
SpectraQuest Inc., 8201 Hermitage Road, Richmond, VA 23228
Published: May 2005
Abstract
In this tech-note, we study the
following: how the natural frequencies get excited
for belts in differing lengths, correlation
between machine operating speed and natural frequency excitement, whether
natural frequencies show up in the vibration spectra, belt dynamic stiffness versus static
stiffness, and belt length effect on excitation and
RPM.
Full Text (PDF)
Introduction
All tests were done
on SpectraQuest’s Machinery Fault Simulator (MFS) using two A30 (30
inches long) and two A42 (42 inches long) belts. Data was acquired
using SpectraQuest’s SpectraPad portable data acquisition system, and
analysis was performed with VibraQuest software. Two single axis
accelerometers and one tri-axial accelerometer made by IMI, and one
Monarch strobe light were also used during the test. In order to
eliminate effects of gearing mechanism, the belts were mounted
directly on a block which was mounted on a sliding platform. The
platform could be easily moved to adjust the belt tension.
To excite resonances in the belts, we tried to put
tape on the upper sheave, and a metal ball was taped to each belt. But
it did not excite the belt resonance frequency up to 5000 RPM. In the
end, we had to tape two metal balls on the belts to excite the
resonance within the speed range of operation.
Fig 1:
Comparison for MFS Speed, Belt Speed and
Resonance Frequency, 42-inch Inner Belt
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