PaperChem

This paper analyses the dynamic behaviour of centrifugal milk separator's bearing-rotor system equipped with vibration absorbers. It is shown that rotational milk motion inside the separator causes a centrifugal force that increases dynamic unbalance of the rotor and has a negative effect on performance of the bearings. Mathematical simulation of bearing-rotor system has shown that the rotor rotates at frequency that is outside the resonant frequency region and the amplitude resonances are associated with the bearings and the components of step-up gear. Investigations of vibration transmissibility of vibration damping system have shown that the resonant frequencies are outside the rotor resonance interval and damping system suppresses the effect of separator with milk on rotor bearings and housing. However, it distorts results of diagnostic measurements. Experimental studies confirmed the last statement and showed that results of indirect (through the housing) vibration measurements cannot be used to diagnose the state of damped bearing-rotor system.

The paper deals with the fault diagnostic system of centrifugal milk separator’s rotor bearings with vibration dampers. The diagnostic system consists of a number of accelerometers attached to the outer ring of the upper bearing of the rotor and the separator’s housing. Such a system allows measuring bearing outer ring vibrations directly and indirectly (through the housing) and at the same time it allows to evaluate the impact of bearing vibration dampers. Direct and indirect bearing vibration measurement results and the differences between them are presented in the paper as well as the relationship between the vibration acceleration and excitation force spectra.

The peculiarities of constructing a model of an individual vehicle moving along the urban street are investigated. The aim of the study is to construct a dynamic vehicle-environment-driver model, which enables to implement the situation' an individual vehicle moving along urban streets', taking into consideration a concrete type of a vehicle, its loading, driver's behavior, peculiarities of external characteristics of internal combustion engines run on traditional or alternative fuel as well as the use og hybrid power plants.