Experimental verification of resonant frequencies and vibration behaviour of stators of electrical machines. Part 2: Experimental investigations and results

1981 ◽  
Vol 128 (1) ◽  
pp. 22 ◽  
Author(s):  
S.P. Verma ◽  
R.S. Girgis
Keyword(s):  
Experimental Verification ◽  
Electrical Machines ◽  
Experimental Investigations ◽  
Resonant Frequencies

scholarly journals A New Concept for Deeper Integration of Converters and Drives in Electrical Machines: Simulation and Experimental Investigations

Open Physics ◽  
2019 ◽  
Vol 17 (1) ◽  
pp. 809-815
Author(s):  
Hossam Al Ghossini ◽  
Thu Thuy Dang ◽  
Stéphane Duchesne
Keyword(s):  
Motor Drives ◽  
Electrical Machines ◽  
Experimental Investigations ◽  
Power Switching ◽  
Switched Reluctance ◽  
High Frequencies ◽  
Reluctance Motor ◽  
Switching Structure ◽  
Very High Frequencies

AbstractThis paper introduces a new concept for integrated electrical motor drives (IEMD) with the aim of minimizing the number of inverter’s power switching components. The latter is switched reluctance motor (SRM) based. The control strategy is jointly designed, inspired by Flyback power supplies operating at very high frequencies. A simple case study on an 8/6 SRM has been carried out. The study enables to highlight most challenging problems that have to be overcome in future works: overvoltages during switching due to the flux leakage, and the efficiency of the magnetic material constituting the machine at high switching frequencies. This concept turns out to be an interesting basis for a very advanced integration of the switching structure within electrical machines.

scholarly journals Modeling of Pressure Drop During Refrigerant Condensation in Pipe Minichannels

2017 ◽  
Vol 38 (4) ◽  
pp. 15-28 ◽  
Author(s):  
Małgorzata Sikora ◽  
Tadeusz Bohdal
Keyword(s):  
Mathematical Model ◽  
Pressure Drop ◽  
Computer Modeling ◽  
Experimental Verification ◽  
Flow Resistance ◽  
Experimental Results ◽  
Experimental Investigations ◽  
Flow Conditions ◽  
Conservation Equations ◽  
Mathematical And Computer Modeling

Abstract Investigations of refrigerant condensation in pipe minichannels are very challenging and complicated issue. Due to the multitude of influences very important is mathematical and computer modeling. Its allows for performing calculations for many different refrigerants under different flow conditions. A large number of experimental results published in the literature allows for experimental verification of correctness of the models. In this work is presented a mathematical model for calculation of flow resistance during condensation of refrigerants in the pipe minichannel. The model was developed in environment based on conservation equations. The results of calculations were verified by authors own experimental investigations results.

scholarly journals Reinvestigation on Assessing the Stability of Mullagulov Tested Steel Rods under Follower Forces

2022 ◽  
Vol 30 (1) ◽  
pp. 801-811
Author(s):  
Jakkana Peter Praveen ◽  
Boggarapu Nageswara Rao
Keyword(s):  
Experimental Verification ◽  
Material Properties ◽  
Dynamic Instability ◽  
Experimental Investigations ◽  
Practical Realization ◽  
Elastic Structures ◽  
The Subject ◽  
Follower Forces ◽  
The Stability ◽  
Critical Overview

Dynamic instability is an interesting topic in the mechanics of elastic structures. Though the subject has been formed by many analytical, numerical, and experimental investigations, it has many issues, as evidenced from the critical overview of Elishakoff. Furthermore, the controversial articles of Koiter and Sugiyama on unrealistic and realistic follower forces demand experimental verification. Mullagulov has proposed a device for creating the follower forces and tested steel rods under compression. This paper highlights the experimentation of Mullagulov and his observations briefly to examine the influence of material properties on the stability load estimations and to confirm the practical realization of follower forces.

A Theoretical and Experimental Study of Vibrations of Thick Circular Cylindrical Shells and Rings

1988 ◽  
Vol 110 (4) ◽  
pp. 533-537 ◽  
Author(s):  
R. K. Singal ◽  
K. Williams
Keyword(s):  
Cylindrical Shells ◽  
Three Dimensional ◽  
Free Vibrations ◽  
Theory Of Elasticity ◽  
Frequency Equation ◽  
Experimental Investigations ◽  
Resonant Frequencies ◽  
Modes Of Vibration ◽  
Circular Cylindrical Shells ◽  
Experimental Values

The free vibrations of thick circular cylindrical shells and rings are discussed in this paper. The well-known energy method, which is based on the three-dimensional theory of elasticity, is used in the derivation of the frequency equation of the shell. The frequency equation yields resonant frequencies for all the circumferential modes of vibration, including the breathing and beam-type modes. Experimental investigations were carried out on several models in order to assess the validity of the analysis. This paper first describes briefly the method of analysis. In the end, the calculated frequencies are compared with the experimental values. A very close agreement between the theoretical and experimental values of the resonant frequencies for all the models was obtained and this validates the method of analysis.

Experimental Verification of Slipper Spinning Motion in Axial Piston Pumps

2017 ◽  
Author(s):  
Qun Chao ◽  
Junhui Zhang ◽  
Qiannan Wang ◽  
Bing Xu ◽  
Yuan Chen
Keyword(s):  
Experimental Verification ◽  
Experimental Investigations ◽  
Test Rig ◽  
Plate Interface ◽  
Pump Operation ◽  
Axial Piston Pumps ◽  
Swash Plate ◽  
Lubrication Characteristics ◽  
Spinning Speed ◽  
Axial Piston

As one of the micro motions of slipper in axial piston pumps, the slipper spinning motion has a significant effect on the lubrication characteristics of slipper/swash plate interface. However, no experimental investigations on the slipper spin were available in previous studies. The aim of this work is to design a novel test rig to measure the slipper spinning speed. A detailed description of this test rig will be given followed by a sample result of the slipper spinning motion. Also, a simulation model considering the slipper spin will be developed to investigate the effects of the spinning motion on the slipper performance. It can be concluded that the slipper spinning motion does exist during pump operation, which is helpful to prevent the slipper from further tilting motion.

scholarly journals Development and Experimental Verification of a Generative CAD/FEM Model of an External Fixation Device

2020 ◽  
Vol 14 (1) ◽  
pp. 1-6
Author(s):  
Elmedin Mešić ◽  
Adil Muminović ◽  
Mirsad Čolić ◽  
Marin Petrović ◽  
Nedim Pervan
Keyword(s):  
Experimental Verification ◽  
Testing Machine ◽  
Parametric Modeling ◽  
Experimental Investigations ◽  
Fixation Device ◽  
Connecting Rod ◽  
Principal Stresses ◽  
Fem Model ◽  
Cad Cam ◽  
Von Mises

This paper presents the development and experimental verification of a generative CAD/FEM model of an external bone fixation device. The generative CAD model is based on the development of a parameterized skeleton algorithm and sub-algorithms for parametric modeling and positioning of components within a fixator assembly using the CATIA CAD/CAM/CAE system. After a structural analysis performed in the same system, the FEM model was used to follow interfragmentary fracture displacements, axial displacements at the loading site, as well as principal and Von Mises stresses at the fixator connecting rod. The experimental analysis verified the results of the CAD/FEM model from an aspect of axial displacement at the load site using a material testing machine (deviation of 3.9 %) and the principal stresses in the middle of the fixator connecting rod using tensometric measurements (deviation of 3.5 %).The developed model allows a reduction of the scope of preclinical experimental investigations, prediction of the behavior of the fixator during the postoperative fracture treatment period and creation of preconditions for subsequent structural optimization of the external fixator.

scholarly journals Investigation of the opportunities for experimental research of gear trains vibrations

2019 ◽  
Vol 287 ◽  
pp. 03001
Author(s):  
Svetlin Stoyanov ◽  
Vasko Dobrev ◽  
Antoaneta Dobreva
Keyword(s):  
Dynamic Behaviour ◽  
Gear Train ◽  
Machine Design ◽  
Experimental Investigations ◽  
Test Device ◽  
Resonant Frequencies ◽  
Linear Character ◽  
Resonance Zone ◽  
Gear Trains ◽  
Loss Of Contact

The improvement of the dynamic and exploitation characteristics of power transmissions is a significant and important problem. The solution of this problem becomes possible through improving the methods in the area of machine design and the existing approaches in experimental investigations. The vibrations in different technical systems including driving systems and power transmissions increase the noise level and the dynamic load. Therefore, the frequency analysis of these systems is especially important. The theoretical analysis of the dynamic behaviour of gear trains indicates that the vibrations in the area of the resonance zone display non-linear character as a result of partial or complete loss of contact in the meshing. The objective of the research presented is to investigate the dynamic behaviour of gear trains. An experimental test device for measuring, processing and analysis of the gear train vibrations has been deigned. The opportunities for data processing in an environment of LabVIEW and/or MATLAB aiming to obtain in an experimental way relationships demonstrating acceleration and resonant frequencies. Conclusions and recommendations have been summarized.

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