First International Conference on MOLDAVIAN RISKS – FROM ...

<strong>First</strong> <strong>International</strong> <strong>Conference</strong> on MOLDAVIAN RISKS - FROM GLOBAL TO LOCAL SCALE
16-19 May 2012, Bacau, Romania
STUDY UPON THE ADVANTAGES OF PREDICTIVE
MAINTENANCE IN MONITORING OF ROLLING BEARINGS
Dumitru-Cristinel Nadabaica, Valentin Nedeff, Luminita Bibire, Gabriela
Andrioai
“Vasile Alecsandri” University of Bacau, Department of Environmental Engineering and
Mechanical Engineering
Corresponding author: Dumitru-Cristinel Nadabaica, nadabaica.dumitru@ub.ro
Abstract: This paper presents a theoretical study of the application of vibration envelope
technique in the diagnosis of rolling bearings with the purpose of estimating their
remaining lifetime and of determining the most advantageous time to perform the
replacement of rolling bearings in the maintenance activity. Rolling bearings are the most
common components of dynamic equipments and they are also the most sensitive to
stresses during operation. The increasing of level vibration contributes to the reduction of
the rolling bearings lifetime. The envelope is a technique of vibration signal processing
which is required for the extraction of the defect characteristic frequency from the
frequency spectrums. By using the envelope technique the premature wear of rolling
bearings can be monitored. Rolling bearings are predisposed to a premature wear due to
the execution and mounting quality, to the loading conditions during operation, to the very
numerous cycles of operation etc. The premature wear is manifested by:
1. the generation of noise (noise pollution);
2. the loss of lubricant (high consumption of raw materials, environmental pollution);
3. the failure of other components (leading to the out of use of the rolling bearing, in a
premature stage, which means both supplementary consumption of materials and energy
for producing new components, and indirectly for increasing the amount of waste);
4. extra energy consumption (one third of all energy is consumed to defeating of unwanted
friction).
This study also presents the benefits of the predictive maintenance application in direct
connection to the minimization of waste quantities and to the environmental pollution. In
the same time, by condition monitoring and diagnostic of process equipment, the
predictive maintenance has an important role about costs of maintenance activity because
one third of these costs are lost because the application of improper or unnecessary
maintenance. Damages made by an improper maintenance can cause disasters at a large
scale, having negative consequences for people and for the environment.
Keywords: predictive maintenance, enveloping technique of vibration, noise pollution, minimization
of waste quantities, consumption of materials and energy.
66