Behaviour diagnostics of drive units on bucket wheel excavators

Dijagnostika ponašanja pogonskih grupa na rotornom bageru je sublimacija analitičkog preseka stanja, numeričkog modela preko metode konačnih elemenata i izmerenih vibracija na karakterističnim mestima pogonskih grupa, odnosno daje se metodološki pristup utvrđivanja ponašanja pogonskih grupa na rotornom bageru u cilju njihove dalje revitalizacije. Pristup rešavanju problema je koncepcijski strogo definisan – analitički segment kojim se ulazi u problem modeliranje problema kao smernica za donošenje inženjerskog stava, i eksperimentalni deo koji treba da potvrdi ispravnost i tačnost metodologije u funkciji otkrivanja uzroka anomalije i njenog preventivnog otklanjanja ili donošenja ispravne odluke.Behaviour diagnostics of drive units on the bucket wheel excavator represents sublimation of analytical state estimation, numerical model based on finite elements method and measured values of the vibrations at the drive units typical locations. Namely, methodological approach in the behavior determination process for bucket wheel excavators drive units is presented for the purpose of its further revitalization. Problem resolving approach is conceptually strictly defined – analytical segment for initial insight of the problem, problem modeling as the line for establishing the engineering position and finally experimental part designated for confirming the accuracy and precision of the methodology with the purpose of locating the causes of anomaly and preventive remediation, or making the right decision

Behaviour diagnostics of drive units on bucket wheel excavators

Dijagnostika ponašanja pogonskih grupa na rotornom bageru je sublimacija analitičkog preseka stanja, numeričkog modela preko metode konačnih elemenata i izmerenih vibracija na karakterističnim mestima pogonskih grupa, odnosno daje se metodološki pristup utvrđivanja ponašanja pogonskih grupa na rotornom bageru u cilju njihove dalje revitalizacije. Pristup rešavanju problema je koncepcijski strogo definisan – analitički segment kojim se ulazi u problem modeliranje problema kao smernica za donošenje inženjerskog stava, i eksperimentalni deo koji treba da potvrdi ispravnost i tačnost metodologije u funkciji otkrivanja uzroka anomalije i njenog preventivnog otklanjanja ili donošenja ispravne odluke.Behaviour diagnostics of drive units on the bucket wheel excavator represents sublimation of analytical state estimation, numerical model based on finite elements method and measured values of the vibrations at the drive units typical locations. Namely, methodological approach in the behavior determination process for bucket wheel excavators drive units is presented for the purpose of its further revitalization. Problem resolving approach is conceptually strictly defined – analytical segment for initial insight of the problem, problem modeling as the line for establishing the engineering position and finally experimental part designated for confirming the accuracy and precision of the methodology with the purpose of locating the causes of anomaly and preventive remediation, or making the right decision

Validation of bucket wheel drive component model through vibration monitoring: a torque arm key study

During excavation, the drive assembly of the bucket wheel of a bucket-wheel excavator is exposed to active and reactive forces. These forces often have adverse effects on the drive assembly, especially if the system has not been adequately sized (poor geometry) and if loads are not properly introduced into the supports (proper positioning of supports). The design of certain drive assemblies includes a torque arm, whose role is to protect the drive assembly from reactive forces. In other words, the torque arm needs to introduce reactive forces into a very stiff system via a support (in the present case the boom of the bucket wheel). Following installation of the new bucket wheel drive on excavator SRs1300.26/5+VR, vibrations were measured at characteristic points to validate the numerical model. Special attention was devoted to the dynamic performance of the torque arm because it is a potential source of failure. The optimization/validation of the bucket wheel torque arm of excavator, aimed at extending the life cycle of both the drive assembly and its components, is discussed in the paper

Redesigning components of power transmission according to numerical model and vibration diagnostics

This article presents derived methodological procedure of redesigning shaft, gear box, bucket wheel of bucket wheel excavator. Method of finite elements has been used for defining numerical model of shaft. As validation of the model, measurements of vibrations at characteristic points of gear box have been used. Obtained data in frequency domain proved correctness. This analysis is made for gear box of bucket wheel on bucket wheel excavator SRs2000 which operates at Kostolac coal basin in Serbia. On this basis, reconstruction of this structure has been performed

Reliability of rubber conveyor belts as a part of the overburden removal system - case study: tamnava-east field open cast mine

This paper identifies the rubber belt conveyers' reliability function, operating on machines (bucket-wheel excavator, beltwagon, spreader) removing overburden on the Tamnava - East Field Open Cast Mine, depending on the belt length and operating time. The proposed methodology used to analyse operating time until failure is the basis to identify the reliability function. The methodology is based on the fact that belt operating time until failure may be represented by the composition of exponential distribution (sudden failures) and normal distribution (gradual failure), as well as on the fact that there is linear dependence between the belt length and the mean operating time until gradual failures. The proposed methodology and reliability function may be applied to analyse operation of other open cast mines, with certain adjustments, to provide better downtime planning, spare rubber belts planning, as well as to reduce open cast mine operating costs, i.e. optimal maintenance strategy

Reliability of rubber conveyor belts as a part of the overburden removal system − case study: Tamnava-east field open cast mine

U radu je određena funkcija pouzdanosti gumenih traka na transporterima, koji rade na strojevima (rotorni bager, transporter, odlagač) pri otkopavanju jalovine na površinskom kopu "Tamnava Istočno polje", u ovisnosti o duljini trake i vremenu rada. Osnovu za određivanje funkcije pouzdanosti predstavlja predložena metodologija analize vremena rada do otkaza gumenih traka koja se temelji na činjenici da se vrijeme rada trake do otkaza može predstaviti kompozicijom eksponencijalne raspodjele (vrijeme rada do naglih otkaza) i normalne raspodjele (vrijeme rada do postepenih otkaza) kao i činjenici da postoji linearna ovisnost između duljine trake i srednjeg vremena rada do postepenih otkaza. Predložena metodologija kao i funkcija pouzdanosti mogu se, uz odgovarajuća prilagođavanja, primijeniti pri analizi rada drugih površinskih kopova radi kvalitetnijeg planiranja zastoja, potrebe za rezervnim gumenim trakama kao i za smanjenje troškova u radu površinskog kopa, tj. mogu ukazati na primjenu kvalitetnije (optimalne) strategije u održavanju.This paper identifies the rubber belt conveyers’ reliability function, operating on machines (bucket-wheel excavator, beltwagon, spreader) removing overburden on the Tamnava – East Field Open Cast Mine, depending on the belt length and operating time. The proposed methodology used to analyse operating time until failure is the basis to identify the reliability function. The methodology is based on the fact that belt operating time until failure may be represented by the composition of exponential distribution (sudden failures) and normal distribution (gradual failure), as well as on the fact that there is linear dependence between the belt length and the mean operating time until gradual failures. The proposed methodology and reliability function may be applied to analyse operation of other open cast mines, with certain adjustments, to provide better downtime planning, spare rubber belts planning, as well as to reduce open cast mine operating costs, i.e. optimal maintenance strategy

Vibration as deciding parameter during revitalization process for replacing the bucket wheel drive

After years of excavator`s operation in adverse conditions, one can expect a ratio between the bucket wheel drive and bucket wheel boom which may lead to impairment of structural integrity. Finite elements method is defined as a diagnostic tool for the anomalies occurrence prevention during operation, and the measured acceleration as a proof of the model’s correctness i.e. revitalization procedure. New solution of the bucket wheel drive reconstruction and revitalization (drive group replacing) is derived on the basis of detailed stress analysis, calculation results and measured accelerations at characteristic points. Operation life of the bucket wheel excavator is directly dependent of the steel structure durability. It is shown in practice that timely replacement of an old, irregular bucket wheel drive has a positive effect on the behavior of tubular structures of the bucket wheel boom. Experimental acceleration measurements must provide support to the numerical model based on finite elements method, which is main diagnostic tool

Extensive vibrations of the belt conveyor drive electromotor of a bucket wheel excavator as a result of intensified wear-and-tear of its mount support

The results of vibration measurements at characteristic points on the belt conveyor drive of bucket wheel excavatorSRs400 manufactured by Takraf are presented in the paper. The operating processes (transport of material on the belt conveyor) belong to the category of impacts, such as fitting, acceleration, sudden loading, and the like, which are extremely pronounced in mining machinery. For monitoring purposes, measurement was undertaken in all three directions, upon overhaul and after 11,850 hours of operation. Movement, speed and acceleration of oscillations were plotted using measured data and the effect of the rear connection of the electromotor mount support on its proper performance was determined

Identification of modular firefighting superstructures’ dynamic behaviour

Specific functional requirements for firefighting vehicles have resulted in stricter exploitation regimes and frequent off-road use. Current practice appoints the problem of the strength of a superstructure’s modules, which are very different in terms of torsional rigidity. It is important to say here that there are no unambiguous manufacturer’s guidelines for bodybuilders to complete a firefighting vehicle. In such circumstances, the identification of the dynamic behaviour of modular firefighting superstructures further gains in importance. Developed numerical-experimental approach for identification, analysis and optimisation of the dynamic behaviour of modular firefighting vehicle superstructures is shown. Experimental part of this method is based on excitation of superstructure physical models with, for this purpose specially developed mechanical exciter. Also, natural frequencies of structures, important in terms of resonant zones, are obtained using bump test and FFT analysis. Finite elements method is defined as a diagnostic tool for the identification of structure behaviour, and the measured acceleration values at characteristic points as a proof of the model’s correctness i.e. correctness of the applied optimisation approach. The numerical analysis of influence of suspension characteristics and connections of superstructure modules on their dynamic behaviour (eigen-frequencies and amplitudes) are also presented. Comparative analysis of the experimental and numerical results verified the numerical model. Such a model can save the time and money by reducing the experiments needed in the modular firefighting vehicle superstructures optimisation

Extensive vibrations of the belt conveyor drive electromotor of a bucket wheel excavator as a result of intensified wear-and-tear of its mount support

The results of vibration measurements at characteristic points on the belt conveyor drive of bucket wheel excavatorSRs400 manufactured by Takraf are presented in the paper. The operating processes (transport of material on the belt conveyor) belong to the category of impacts, such as fitting, acceleration, sudden loading, and the like, which are extremely pronounced in mining machinery. For monitoring purposes, measurement was undertaken in all three directions, upon overhaul and after 11,850 hours of operation. Movement, speed and acceleration of oscillations were plotted using measured data and the effect of the rear connection of the electromotor mount support on its proper performance was determined