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Abstract

Designing touch-down bearings (TDB) for outer rotor flywheels operated under high vacuum conditions constitutes a challenging task. Due to their large diameters, conventional TDB cannot suited well, and a planetary design is applied, consisting of a number of small rolling elements distributed around the stator. Since the amplitude of the peak loads during a drop-down lies close to the static load rating of the bearings, it is expected that their service life can be increased by reducing the maximum forces. Therefore, this paper investigates the influence of elastomer rings around the outer rings in the TDB using simulations. For this purpose, the structure and the models used for contact force calculation in the ANEAS simulation software are presented, especially the modelling of the elastomers. Based on the requirements for a TDB in a flywheel application, three different elastomers (FKM, VMQ, EPDM) are selected for the investigation. The results of the simulations show that stiffness and the type of material strongly influence the maximum force. The best results are obtained using FKM, leading to a reduction of the force amplitude in a wide stiffness range.
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Bibliography

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  2.  L. Quurck, D. Franz, B. Schüßler, and S. Rinderknecht, “Planetary backup bearings for high speed applications and service life estimation methodology,” Mech. Eng. J., vol. 4, no. 5, 2017, doi: 10.1299/mej.17-00010.
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Authors and Affiliations

Benedikt Schüßler
1
ORCID: ORCID
Timo Hopf
1
ORCID: ORCID
Stephan Rinderknecht
1
ORCID: ORCID

  1. Technical University of Darmstadt, Institute for Mechatronic Systems, Germany
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Abstract

The article presents the analysis results of the effectiveness limitation of the step voltage by forming an electric field on the ground surface. For shaping the electric field, a method consisting of screens placed around the point of the earth current flow was used. The analysis was performed using an example of an MV/LV substation grounding system. This research was conducted applying a mathematical model of the grounding system and screens by means of the finite element method. The influence of metal, insulating screens and surface material on the step/touch voltage values for the considered grounding system was estimated. Most of the methods described can be applied in practice. In the opinion of the authors, the method of using screens made of insulating and conductive materials has not been sufficiently described in the literature. Moreover, in the available literature there is no in-depth analysis of the described electric field shaping methods.
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Bibliography

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Authors and Affiliations

Roman Sikora
1
ORCID: ORCID
Przemysław Markiewicz
1
ORCID: ORCID

  1. Institute of Electrical Power Engineering, Lodz University of Technology, Stefanowski str. 18/22, 90-924 Lodz, Poland
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Abstract

The paper offers a reappraisal of the Puławy collection’s display through a detailed analysis of Virgilian evocations within the complex. The choice of inscriptions and ancient imagery framing the exposition’s narrative, as well as the surviving reception testimonies towards such strategies within Pulavian pavilions, demonstrate an ongoing questioning of chronological sequences, the primacy of authenticity, and aestheticising exhibits. Such anachronic distancing from a historicizing temporality would take place in favour of an intimate experience of familial-cum-national memorabilia, in accordance with the contemporaneously emerging category of the fetish.
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Authors and Affiliations

Aleksander Musiał
1
ORCID: ORCID

  1. Princeton University
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Abstract

The touch trigger probe plays an important role in modern metrology because of its robust and compact design with crash protection, long life and excellent repeatability. Aside from coordinate measuring machines (CMM), touch trigger probes are used for workpiece location on a machine tool and for the accuracy assessment of the machine tools. As a result, the accuracy of the measurement is a matter of interest to the users. The touch trigger probe itself as well as the measuring surface, the machine tool, measuring environment etc. contribute to measurement inaccuracies. The paper presents the effect of surface irregularities, surface wetness due to cutting fluid and probing direction on probing accuracy on a machine tool.

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Authors and Affiliations

Md. Mizanur Rahman
J.R.R. Mayer
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Abstract

The article provides a theoretical basis for a method allowing to calculate probability of effects of electric shock, as well as a method for determining probabilistic characteristics of random touch current values and of human body impedance in a person who suffered from specific effects of electric shock. Results of example calculations are presented, including probabilities of occurrence of sensory symptoms, exceeding the letgo threshold, and development of ventricular fibrillation, as well as probabilistic characteristics of random touch current values and of impedance of human body in people who experienced specific effects of electric shock.

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Authors and Affiliations

Włodzimierz Korniluk
Dariusz Sajewicz
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Abstract

The article describes a shock safety modeling method for low-voltage electric devices, based on using a Bayesian network. This method allows for taking into account all possible combinations of the reliability and unreliability states for the shock protection elements under concern. The developed method allows for investigating electric shock incidents, analysing and assessing shock risks, as well as for determining criteria of dimensioning shock protection means, also with respect to reliability of the particular shock protection elements. Dependencies for determining and analysing the probability of appearance of reliability states of protection as well as an electric shock risk are presented in the article.
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Authors and Affiliations

Włodzimierz Korniluk
Dariusz Sajewicz
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Abstract

The article presents a shock safety model of an indirect contact with a low-voltage electric device. This model was used for computations and analyses concerning the following: the probabilities of appearance of the particular shock protection unreliability states, electric shock states (ventricular fibrillation), contributions of the unreliability of different shock protection elements to the probability of occurrence of these states, as well as the risk of electric shock (and the shock safety), and contributions of the intensity of occurrence of damages to different shock protection elements to this risk. An example of a possibility to reduce the risk of an electric shock through changing the intensity of occurrence of damages to the selected protection elements was provided.

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Authors and Affiliations

Włodzimierz Korniluk
Dariusz Sajewicz

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