Effects of the Electromagnetic Forces on Vibrational Behavior of the Laminated Mechanical Structure of Stator Cores

1995 ◽  
Author(s):  
Cuneyt Ozturk
Keyword(s):  
Material Properties ◽  
Significant Contribution ◽  
Experimental Methods ◽  
Inertial Forces ◽  
Combined Effects ◽  
Electric Motors ◽  
Stator Core ◽  
Electromagnetic Forces ◽  
Mechanical Structure ◽  
Magnetostrictive Deformation

Abstract Stator laminations can have mutual excitation sources depending to the inertial forces that can excite the mechanical resonances and radial components of the electromagnetic forces that vary with the magnetic flux changes and the magnetostrictive forces. Magnetostrictive forces can appear depending to the material properties of the plates and have mechanical and magnetic causes Mechanical properties of the lamination plates can be determined both in numerical and experimental methods. Magnetostrictive effects of the laminations have significant contribution to the audible noise of electric motors. The combined effects of radial components of electromagnetic forces and magnetostrictive deformation can cause further amplification problems of noise. This study investigates the effects of magnetostrictive forces on the laminated mechanical structure of stator core by referring to the changes of the plate materials depending to applicable heat treatments, magnetic properties and silicon alloying that were all considered as factors to modify the effects of magnetostriction.

Experimental Identification of Material Properties of Piezoelectric Patch Transducer

2013 ◽  
Vol 486 ◽  
pp. 205-210
Author(s):  
Zuzana Lašová ◽  
Robert Zemcik
Keyword(s):  
Health Monitoring ◽  
Material Properties ◽  
Element Model ◽  
Experimental Methods ◽  
Optical Microscope ◽  
Piezoelectric Patch ◽  
Experimental Identification ◽  
Substrate Structure ◽  
Significant Difference ◽  
Voltage Signal

This work is focused on identification of material properties of piezoelectric patch transducers used e.g. for structural health monitoring before attaching to the substrate structure. Two experimental methods were concerned. At first two piezoelectric patches were supplied with a pair of collocated strain gauge rosettes. Both transducers were actuated with the same periodical signal. Significant difference in the results for two transducers was found, however it was claimed to be within tolerance by the producer. As an alternative method a measurement in an optical microscope was chosen. The patch was clamped at one side and actuated by a voltage signal. The displacement of the free end was captured by the microscope and processed in a graphical editor. Finally, a finite element model of the transducer was created and its material data were obtained by calibration with experimental data.

Tribological performance characterization of brake friction materials: What test? What coefficient of friction?

2018 ◽  
Vol 233 (1) ◽  
pp. 214-226 ◽  
Author(s):  
Mohamed Kchaou ◽  
Amira Sellami ◽  
Jamal Fajoui ◽  
Recai Kus ◽  
Riadh Elleuch ◽  
...  
Keyword(s):  
Material Properties ◽  
Experimental Methods ◽  
Tribological Performance ◽  
Small Sample ◽  
Large Field ◽  
Friction Materials ◽  
Braking Performance ◽  
Specific Protocol ◽  
Reduced Scale

This article describes and explains the tribological tests and methods for the evaluation of the performance of the brake friction materials. It starts by discussing the particularities of these materials and the variation of characterization tests, which can experimentally simulate many aspects of brake situation but with a large field of tribo-test, from standard to specific protocol. Examples of preparation, procedures, instrumentation, and analysis results for the tribological aspect testing ranging from the scale of vehicle braking performance (by methods including inertia dynamometers, Krauss testing, friction assessment screening test, and Chase testing) to simplified test using reduced-scale prototypes for small-sample friction, are explained. A particular attention is attributed to the discussion of the viability of the friction coefficient report in relation to the material properties and brake compound performance. At the end of this article, the guarantee of the performance output or ranking evaluated by such experimental methods is discussed.

An Organisational Approach to Analysis of Policy Innovation by Local Authorities in Britain: The Importance of the Concepts of Scrutiny, Conflict, and Centralisation

1988 ◽  
Vol 6 (2) ◽  
pp. 159-172 ◽  
Author(s):  
F J Burdett ◽  
M G Bradford
Keyword(s):  
Significant Contribution ◽  
New Technology ◽  
Policy Innovation ◽  
Combined Effects ◽  
Policy Outcome ◽  
Public Provision ◽  
Local Authorities ◽  
Organisation Theory ◽  
Adoption Of New Technology ◽  
Technology In Schools

In this paper an organisational approach is used to study the timing, duration, and outcome of the policymaking on public provision of local authorities. The organisation is considered as an intervening analytical level that bridges the gap between the effect of individual actors and that of the structure of society on the geography of public provision. Drawing on the literature of organisation theory, we analyse the effects of processes within organisations to help explain variation in public provision between authorities. The separate and combined effects of three major organisational concepts are examined: Scrutiny, conflict, and centralisation. These concepts are applied to policy innovation in four English local authorities, and specifically to their policies for the adoption of new technology in schools. Although the separate effects of the concepts help our understanding, it is their interaction which makes a significant contribution to the explanation of the timing and duration of policy innovation, as well as explaining the policy outcome, which was the aim of most previous work. Further understanding is gained when these concepts are set within the context of the overall structure and behaviour of the organisation.

Modeling of airgap flux density for the study of stator core vibration in low speed synchronous machines

2020 ◽  
Vol 39 (4) ◽  
pp. 839-852
Author(s):  
Allan De Barros ◽  
Ivan Chabu
Keyword(s):  
Field Distribution ◽  
Stator Winding ◽  
Stator Core ◽  
Electromagnetic Forces ◽  
Content Type ◽  
Low Speed ◽  
Relative Evaluation ◽  
Tangential Forces ◽  
The Given ◽  
Damper Winding

Purpose This paper aims to develop models and simulations focused on the prediction of electromagnetic forces acting on the stator core of a synchronous machine. It contributes to the study of stator core vibrations. Design/methodology/approach An analytical model based on the rotating fields’ theory including the damper winding contribution was developed. Such model allows the comprehension of airgap magnetic field distribution and the consequent pressure distribution. Focus was given to the pressure sub-harmonics due to the usual fractional winding configuration of low speed machines. A comparative numerical model was also developed and applied to an example laboratory machine. Partial validation measurements were performed. Findings The paper provides the predicted electromagnetic forces and the relative influences of damper winding and teeth tangential forces on each pressure harmonic. It is shown by how much such effects can influence the amplitude of pressure sub-harmonics from a fractional stator winding. Research limitations/implications The performed validation measurements were based on the airgap field distribution, but the resulting core vibration at load was not measured. Therefore, researchers are encouraged to perform additional tests for improved validation. Practical implications The obtained models and results are of great importance for the design phase of new generators and for the diagnosis process of existing machines with core vibration problems. Originality/value As a contribution of this paper, the magnitude of indirect effect of tangential forces and the effect of damper winding are comparatively quantified for each pressure harmonic. The given approach contributes to the relative evaluation of these effects especially on the sub-harmonics from the fractional stator winding.

scholarly journals Evaluation of frame-induced compressive stress on the magnetic properties of stator cores using the excitation inner core method

2018 ◽  
Vol 69 (6) ◽  
pp. 477-480
Author(s):  
Mohachiro Oka ◽  
Masato Enokizono
Keyword(s):  
Magnetic Properties ◽  
Compressive Stress ◽  
Inner Core ◽  
Iron Loss ◽  
Electric Motors ◽  
Stator Core ◽  
Core Method

Abstract To improve the efficiency of electric motors, we developed the excitation inner core method to evaluate the magnetic properties such as the iron loss of the actual stator core. After preparing two stator cores with a frame, we examined the frames influence of compressive stress by applying the standard and small excitation inner core methods to evaluate the iron loss of both stator cores having a frame. After removing the frames of the two stator cores, we evaluated the iron loss of two stator cores without the frames again by applying both methods.

scholarly journals The Application of Experimental Methods to Improve Science Learning Outcomes for Fourth Grade Students at Elementary School

2020 ◽  
Vol 3 (4) ◽  
pp. 767
Author(s):  
Aman Sugianto
Keyword(s):  
Learning Outcomes ◽  
Material Properties ◽  
Science Learning ◽  
Fourth Grade ◽  
Experimental Methods ◽  
Student Learning Outcomes ◽  
Reflection Data ◽  
Fourth Grade Students ◽  
Post Test ◽  
Improve Student Learning

<p><em>The purpose of this research was to improve the learning outcomes of fourth grade students at SD Negeri Pabuaran 02 in science subjects through the application of experimental methods. The research that was conducted was Classroom Action Research (CAR) which was carried out in two cycles of action, each cycle consisting of two meetings. The stages for each cycle are planning, implementation, observation and reflection. Data was collected using observation techniques, documentation studies and tests. The results of the first cycle of research showed that students who completed the post-test were 63.6%. In the implementation of the second cycle of students who completed after carrying out the post test was 95.5%. These results indicate that the application of the experimental method can improve student learning outcomes in science subjects Class IV at SD Negeri Pabuaran 02, especially on the material properties of light.</em></p>

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