Tag Archives: reliability

680–686 M. Forsman
The search for practical and reliable observational or technical risk assessment methods to be used in prevention of musculoskeletal disorders
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The search for practical and reliable observational or technical risk assessment methods to be used in prevention of musculoskeletal disorders

M. Forsman

Institute of Environmental Medicine, Karolinska Institutet, SE-171 77 Stockholm, Sweden
Correspondence: mikael.forsman@ki.se

Abstract:

Work-related musculoskeletal disorders (WRMSDs) are still frequent, inducing very large costs for companies and societies all over the world. Ergonomists work to prevent these disorders and to make organisations sustainable. In their work it is important to identify risks in a reliable way, to prioritise risks, and then to perform interventions (participatory interventions have shown to more often be successful), so that the risks and the disorders may be reduced. Risks are most often assessed by observation. Two projects are described. In the first project the interobserver reliability of six observational methods was found to be low in risk assessments concerning repetition, movements and postures. Also the inter-method reliability was often low, i.e. when the same work is assessed with different methods different risk estimates are often obtained. In the second described project, easy-to-use methods for measurements of postures and movements were developed and validated. Hence, there are now validated technical methods that are easy to use. But, today’s inexpensive electronic devices should be utilized to a higher degree, in developing tools, together with practitioners, that are attractive, easy and time efficient to use, and which should increase the reliability in risk assessments of work tasks and jobs.

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817–829 M. Prístavka, K. Krištof, and P. Findura
Reliability monitoring of grain harvester
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Reliability monitoring of grain harvester

M. Prístavka¹, K. Krištof²,* and P. Findura²

¹ Slovak University of Agriculture in Nitra, Faculty of Engineering, Department of Quality and Engineering Technologies, Tr. A. Hlinku 2, SK949 76 Nitra, Slovak Republic
² Slovak University of Agriculture in Nitra, Faculty of Engineering, Department of Machines and Production Biosystems, Tr. A. Hlinku 2, SK949 76 Nitra, Slovak Republic
*Correspondence: koloman.kristof@uniag.sk

Abstract:

This paper is focused on evaluation of operating reliability of grain harvesters. The aim of research is to improve the efficiency of combine harvesters by calculations which indicate a minimum annual performance and try to move in profit despite the high annual costs. Methods of paper containing all conditions of monitoring and evaluating of responsibility of grain harvesters. Those harvesters worked in real operating conditions. During three years of monitoring all important and other facilities and conditions of watching were recorded. After accumulation of information, their following working was set out according to the given literary sources and according to the own discretion based on experience during monitoring. The last part is focused on evaluating results and personal proposals how to make individual components work more effective. The most important results was recorded in case of turning point calculation where in years 2013, 2014 and 2015 at values 157.93, 156.19 and 166.86 ha year-1, respectively. However, real annual performance was recorded at values 760.5, 604.6 and 905.5 ha year-1. Thus, in all years of observation the grain harvester finished in profits.

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1161–1168 A. Gedzurs
Operation reliability of induction motors at egg processing plant ‘Balticovo’
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Operation reliability of induction motors at egg processing plant ‘Balticovo’

A. Gedzurs

Latvia University of Agriculture, Faculty of Engineering, Institute of Energetics, J. Cakstes blvd. 5, LV-3001 Jelgava, Latvia; e-mail: aleksejs.gedzurs@llu.lv

Abstract:

In hen houses air quality plays an important role in egg production volume. However, failure of fan induction motors often occurs and it is important to improve reliability of these. A motor reliability study was conducted in the egg processing plant ‘Balticovo’ in Iecava. Results show that 86% of failed number from 2010–2015 occur in hen houses and more than 50% of them were failures of motors which drive the fan. Annual failure rate of fan induction motors each year was increasing and in 2015 it was 6%. Investigations of the faulty motors showed the following defects – stator turn to turn failure of stator winding insulation leadwire and stator winding insulation thermal stress and mechanical damage of stator core resulting in the damaged stator winding leading to a short circuit. Results show that conditions that could contribute to such defects are excessive heating and vibrations.

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