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Squirrel cage induction motors with idle bars

Jakub Bernatt
Archives of Electrical Engineering | 2010 | vol. 59 | No 1 - 2 September | 79-86 | DOI: 10.2478/s10171-010-0006-z
Keywords induction motor squirrel cage idle bar hard working conditions
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Abstract

The paper describes high output induction motors driving large applications of heavy starting conditions. Heavy start is characterised by long accelerating time and occures in drives of hudge inertia torque, esspecially when performed at full load. The reliable operation of the motors depends on proper design and quality of rotor's cage. The aspects of thermal behaviour and electrodynamic forces have to be considered during the design of the motor for hard working conditions. In the paper the rotor with idle bars is investigated.

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Authors and Affiliations

Jakub Bernatt

Comparative study of cooling of automobile LED headlights without and with fins and finding comfortable operating conditions

Manbodh Kumar Mishra V.P. Chandramohan Karthik Balasubramanian
Archive of Mechanical Engineering | 2019 | vol. 66 | No 3 | 295-314 | DOI: 10.24425/ame.2019.129677
Keywords LED lights automobile headlight finite element method junction temperature safe working conditions
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Abstract

LED light must be cooled to avoid reaching a certain temperature. Two different 3D practical domains of LED light are modelled, (i) square aluminium plate with a cylindrical plate and an LED module (model I), (ii) the same provision of model I with 25 fins (model II). ANSYS 16.0 is used for solving the problem. Temperature distribution, junction temperature (Tj) and heat flux are estimated. Analyses are carried out for various ambient temperatures (Ta) and for different LED power dissipations (Q) to identify the safe operating conditions. In model I, it is found that 38% of working conditions go beyond the critical limit of Tj and it is reduced to 21.4% in model II. In model II, for low Ta of 30 and 40ºC with all Q considered in this analysis are safer. If Ta is between 30 and 80ºC, then Q must be maintained at 0.5 to 1.25 W. Beyond this, conditions are not safe.

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Authors and Affiliations

Manbodh Kumar Mishra
1
V.P. Chandramohan
1
Karthik Balasubramanian
1
  1. Department of Mechanical Engineering, National Institute of Technology Warangal, Telangana, India.

Testing surveillance thermal imagers under simulated real work conditions

Krzysztof Chrzanowski
Opto-Electronics Review | 2023 | 31 | 1 | e145327 | DOI: 10.24425/opelre.2023.145327
Keywords thermal imagers variable work conditions extreme conditions thermal imaging metrology
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Abstract

Thermal imagers often work in extreme conditions but are typically tested under laboratory conditions. This paper presents the concept, design rules, experimental verification, and example applications of a new system able to carry out measurements of performance parameters of thermal imagers working under precisely simulated real working conditions. High accuracy of simulation has been achieved by enabling regulation of two critical parameters that define working conditions of thermal imagers: imager ambient temperature and background temperature of target of interest. The use of the new test system in the evaluation process of surveillance thermal imagers can bring about a revolution in thermal imaging metrology by allowing thermal imagers to be evaluated under simulated, real working conditions.
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Authors and Affiliations

Krzysztof Chrzanowski
1 2
ORCID: ORCID
  1.   Institute of Optoelectronics, Military University of Technology, gen. Sylwestra Kaliskiego 2, 00-908 Warsaw, Poland
  2. INFRAMET, Bugaj 29a, Koczargi Nowe, 05-082 Stare Babice, Poland

Precarious Work? Migrants’ Narratives of Coping with Working Conditions in the Danish Labour Market

Doris Pljevaljcic Simkunas Trine Lund Thomsen
Central and Eastern European Migration Review | 2018 | Vol. 7 | No 2 | 35-51
Keywords biographical narratives cultural and social capital labour security migrant workers precarious working conditions
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Abstract

This article deals with migrants’ experiences of precarious working conditions in the cleaning and con-struction industries in the Danish labour market as seen from their perspective. The experiences are retained through biographical narrative interviews with migrant workers from Central and Eastern Europe and are used to gain an understanding of the concrete strategies they apply when coping with their short-term contracts, demanding working hours, risk of unemployment and other insecurities. Mi-grants’ experiences of precarity and insecurity in their work is confirmed, to some degree, in numerous research studies. However, the resistance and strategies expressed by the migrant workers in their nar-ratives show that they have also developed specific ways to cope with this precarity. The article con-tributes to a new understanding of migrants’ responses to precarity in which they engage their social and cultural resources to cope with the labour market conditions they face in Denmark.

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Authors and Affiliations

Doris Pljevaljcic Simkunas
Trine Lund Thomsen

Study of the Social Responsibility of Ukrainian Employers for the Health of Employees on the Example of Enterprises of the Machine-Building Industry in the Kharkiv Region

Ganna Oganezova
Management and Production Engineering Review | 2024 | Vol. 15 | No 2 | DOI: 10.24425/mper.2024.151137
Keywords Employee health The level of social responsibility of the employer Working conditions workplace Industrial health
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Abstract

The work aims to develop a methodical approach to assessing the employer’s level of social responsibility for employee health. Methods of statistical analysis, expert assessments, and content analysis were used. Developed a methodological approach to determining the level of social responsibility of the employer for maintaining the health of workers, which was tested in a sample of 18 enterprises of the machine-building industry of Kharkiv and Kharkiv region; it is determined by calculating an integrated indicator that combines quantitative and qualitative characteristics of the working environment in three planes (sections), which characterize the factors influencing human health: social conditions and lifestyle, the level of ecology of the working space, and the level of medical care at the enterprise. The results of the employer’s efforts to preserve the health of the employee are transformed into the health of the employee, which is analyzed through the indicator “Health Index”.
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Authors and Affiliations

Ganna Oganezova

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