Forced vibrations in twin-engines synchronous drives of rattlers
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- Category: Geotechnical and mining mechanical engineering, machine building
- Last Updated on 25 December 2013
- Published on 19 December 2012
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Authors:
B.V. Vinogradov, Dr. Sci. (Tech.), Professor, State Higher Educational Institution “Ukrainian State University of Chemical Technology”, Head of the Department of Theoretical Mechanics and Resistance of Materials, Dnepropetrovsk, Ukraine
A.V. Khristenko, State Higher Educational Institution “Ukrainian State University of Chemical Technology”, Dnepropetrovsk, Ukraine
Abstract:
Purpose. To develop the technique for calculation of the dynamics of electromechanical systems of two-motor synchronous drives of tumbling mills and substantiate their rational dynamical parameters.
Methodology. The dynamic model of twin-engine synchronous drive is presented by three-mass system. The electromagnetic system of synchronous engine is considered to be an equivalent mechanical model. It is shown, that the forced vibrations in the drive appear as a result of kinematic disturbance, caused by the accumulated error of the gearing step. Experimental dependence of the opened gearing accumulated step error is presented by Fourier series, which allows us to estimate amplitudes of each harmonic kinematic disturbance.
Forced vibrations of the system are described by three linear differential equations. A drive with power of 8000 kW is considered as an example. For each line of transmission the drive of MSHC 55x65 mill with an engine with power of 4000 kW is taken as a standard.
The drive dynamic loading is characterized by dynamic coefficient, showing, how many times the maximal dynamic loading in a drive exceeds amplitudes of kinematic disturbance in every line of transmissions. For the estimation of the dynamic loadings values the gain-frequency characteristics of the engine and mechanical transmissions electromagnetic system is presented for the most loaded branch at the different values of inflexibility of resilient muffs and their antivibration ability. To ensure the clearness of the obtained results the calculated dependencies of twisting moment values on time are given.
Findings. The results of the research show that on fundamental frequency of kinematic disturbance (р1 = 1,5с-1
) the dynamic coefficient does not exceed the value of 1. It means that the maximal dynamic loading in the drive is equal Мдмах = 0,5сеΔk1 
.Limitation of dynamic loadings and uniform distribution of twisting moment static constituent is possible by declining of mechanical transmissions inflexibility. The presence of the kinematic indignation ultraharmonic results in the increase of twisting moment dynamic constituent, especially in cases when one of frequencies corresponds to the resonance. Application of special resilient muffs possessing high antivibration ability allows us to limit the dynamic loadings in the drive and approach them to the value of 
Мдмах = 0,5сеΔk1
Originality. The regularities of dynamic loads formation in the two-motor drives of tumbling mills has been determined.
Practical value. The method of dynamic calculation of twin-engine synchronous drive of tumbling mills, allowing us to choose their rational parameters, has been developed.
 2012_6_vinogradov
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