Propagation Characteristics of Partial Discharge Signals

2010 ◽  
Vol 11 (3) ◽  
Author(s):  
Cheng Pei ◽  
Xiuchen Jiang ◽  
Fang Song
Keyword(s):  
Theoretical Analysis ◽  
Partial Discharge ◽  
Signal Frequency ◽  
Test Results ◽  
Propagation Characteristics ◽  
Signal Attenuation ◽  
Xlpe Cable ◽  
Transmission Properties ◽  
Frequency Properties ◽  
Good Agreement

With the increased use of partial discharge tests to assess the conduction of shielded distribution cable, PD signal frequency properties of such cables have become increasingly important. It is desirable to detect and locate the PD in the cable before breakdown occurs. Understanding the propagation phenomena of the PD signal in XLPE cable is important to detect and locate the PD signal. In this paper, transmission properties of PD signal were measured and analyzed on a 30m length and 15m length of 11 kV XLPE cable in the laboratory . The experimental results show a good agreement with the theoretical analysis. The paper describes the test results and discusses the PD signal attenuation in time and frequency domain and discusses this with reference to practical PD detection.

Analysis of bearing failures in a typical high-power marine gearbox

2018 ◽  
Vol 70 (1) ◽  
pp. 33-41
Author(s):  
Haigang Gu ◽  
Guang Feng ◽  
Yonggang Lin ◽  
Chaozhu Wang
Keyword(s):  
Theoretical Analysis ◽  
Roller Bearing ◽  
Fretting Fatigue ◽  
Test Results ◽  
Content Type ◽  
Bearing Failures ◽  
Manufacturing Errors ◽  
Cylindrical Roller ◽  
Fatigue Failures ◽  
Good Agreement

Purpose This paper aims to analyze fatigue failures of a typical marine gearbox under harsh ocean conditions, and these failures are reasonably attributed to the bearing fretting fatigue damages. Design/methodology/approach Two typical FAG cylindrical roller bearings mounted on this marine gearbox are particularly used for analysis, as they are most vulnerable to these failures. A series of simulations have also been conducted to verify the analysis results and failure reasons by reproducing the fretting fatigue damages for the same shaft-bearing system under the same manufacturing error conditions. Findings The analysis results indicate that manufacturing errors are the most possible reasons for the bearing failures, and these errors have more effects on the FAG cylindrical roller bearing as compared to other bearings mounted on the same shaft system. The simulations results are in good agreement with the theoretical analysis results and test results and hence validate that manufacturing errors are the dominant reasons for bearing fretting fatigue damages in this typical marine gearbox. Originality/value Fatigue failures of a typical marine gearbox. Manufacturing errors are the most possible reasons for the bearing failures. A series of simulations have been conducted to verify the analysis results and failure reasons. The simulations results are in good agreement with the theoretical analysis results and test results.

An Investigation of Face Type Magnetic Couplers

1996 ◽  
Vol 210 (4) ◽  
pp. 263-272 ◽  
Author(s):  
R Waring ◽  
J Hall ◽  
K Pullen ◽  
M R Etemad
Keyword(s):  
Theoretical Analysis ◽  
Optimum Design ◽  
Experimental Test ◽  
Axial Load ◽  
Filling Factor ◽  
Theoretical Calculations ◽  
Test Results ◽  
Face Type ◽  
Design And Manufacture ◽  
Good Agreement

A theoretical analysis of magnetic couplers is recounted, leading to the design and manufacture of prototype disc type magnetic couplers. Design and development of experimental test rigs are also given. Test results are presented and compared with theoretical calculations. This shows very good agreement. The exception to the rule was the case of axial load measurements, which were not accurately evaluated by the computations. The geometries tested here showed the optimum design to consist of rotors with eight poles, magnet thickness of 10 mm and a filling factor of about 0.7.

Theoretical Analysis on Radial Gate Vibration

2006 ◽  
Author(s):  
Kunihiro Ogihara
Keyword(s):  
Theoretical Analysis ◽  
Model Test ◽  
Pressure Change ◽  
Test Results ◽  
New Approach ◽  
Water Gate ◽  
Pipe Line ◽  
Gate System ◽  
Radial Gate ◽  
Good Agreement

The instability analysis on vibration of radial gate has been done in 1999 under the research project In JPGA (Japan penstock and water gate association) and also the model test of gate vibration has been preceded. The almost theoretical results have been satisfied of the model test results, but there is one point not to be able to explain the relation of natural frequency of gate support system. The instable condition is given by the forth power of frequency of gate system in model test, and the fact that the region of instable becomes smaller as the gate opening larger, is same as the results of theoretical analysis. In this paper, author develop the new approach which is considering the pressure change by stopping the water flow same as water hummer in pipe line. And the unstable analysis on vibration equation of radial gate motion has been done and gotten good agreement on model test results.

PHOTOINDUCED NONLINEAR OCTUPOLAR POLARIZATION: TRANSIENT AND PERMANENT REGIMES

1996 ◽  
Vol 05 (04) ◽  
pp. 653-670 ◽  
Author(s):  
CÉLINE FIORINI ◽  
JEAN-MICHEL NUNZI ◽  
FABRICE CHARRA ◽  
IFOR D.W. SAMUEL ◽  
JOSEPH ZYSS
Keyword(s):  
Theoretical Analysis ◽  
Second Harmonic ◽  
Experimental Results ◽  
Polar Field ◽  
Rotational Spectrum ◽  
Dual Frequency ◽  
One Dimensional ◽  
Ethyl Violet ◽  
Disperse Red 1 ◽  
Good Agreement

An original poling method using purely optical means and based on a dual-frequency interference process is presented. We show that the coherent superposition of two beams at fundamental and second-harmonic frequencies results in a polar field with an irreducible rotational spectrum containing both a vector and an octupolar component. This enables the method to be applied even to molecules without a permanent dipole such as octupolar molecules. After a theoretical analysis of the process, we describe different experiments aiming at light-induced noncentrosymmetry performed respectively on one-dimensional Disperse Red 1 and octupolar Ethyl Violet molecules. Macroscopic octupolar patterning of the induced order is demonstrated in both transient and permanent regimes. Experimental results show good agreement with theory.

scholarly journals Spine Examination during COVID-19 Pandemic via Video Consultation

2021 ◽  
Author(s):  
Tom Jansen ◽  
Martin Gathen ◽  
Amadeo Touet ◽  
Hans Goost ◽  
Dieter Christian Wirtz ◽  
...  
Keyword(s):  
Pain Intensity ◽  
Range Of Motion ◽  
Test Results ◽  
Risk Of Infection ◽  
Face To Face ◽  
Reliable Tool ◽  
Provocation Tests ◽  
Active Range Of Motion ◽  
Video Consultation ◽  
Good Agreement

Abstract Introduction During the current COVID-19 pandemic video consultations are increasingly common in order to minimize the risk of infection for staff and patients. The aim of this study was to evaluate the feasibility of a spine examination via video. Methods A total of 43 patients were recruited. Each participant underwent a video-based (VB) and a conventional face-to-face (FTF) spine examination. Pain intensity, active range of motion, inspection, a neurophysiologic basic exam and provocations tests were evaluated using video-based and face-to-face methods. Results The intra-rater reliability (IRR) was measured between both examinations. Good to very good IRR values were obtained in inspection (Kappa between 0,752 und 0,944), active range of motion and basic neurophysiological examination (Kappa between 0,659 und 0,969). Only moderate matches were found in specific provocation tests (Kappa between 0,407 und 0,938). A video-based spine examination is a reliable tool for measuring pain intensity, active range of motion and a basic neurophysiologic exam. Conclusion A basic spine examination during a video consultation is possible. A good agreement of the test results between video-based and face-to-face examination could be found.

Design of combined brake system for light weight scooters

2021 ◽  
pp. 095440702110240
Author(s):  
Yuan-Ting Lin ◽  
Chyuan-Yow Tseng ◽  
Jao-Hwa Kuang ◽  
Yeong-Maw Hwang
Keyword(s):  
Ride Comfort ◽  
Brake System ◽  
Force Distribution ◽  
Test Results ◽  
Systematic Method ◽  
Braking Performance ◽  
Evaluation Indexes ◽  
Low Costs ◽  
Braking Force ◽  
Good Agreement

The combined brake system (CBS) is a mechanism that links the front and rear brakes for scooters. For two-wheeled scooters, a CBS with appropriate braking force distribution can reduce the risk of crashing accidents due to insufficient driving proficiency. The design of the braking force distribution for a CBS is challenging to the designer because it has to fulfill many requirements such as braking performance, ride comfort, reliability, and low costs. This paper proposes a systematic method to optimize the parameters of CBS. The evaluation indexes for the design are first discussed. The steps to determine the critical parameter to meet the indexes and a method to predict braking performance are developed. Finally, driving tests are carried out to verify the effectiveness of the proposed method. Experimental results showed that the deceleration of the tested scooter equipped with the designed CBS achieves an average mean fully developed deceleration (MFDD) of 5.246 m/s2, higher than the homologation requirement. Furthermore, the proposed method’s prediction of braking performance is in good agreement with the test results, with errors <1%.

Study on the stiffness degradation in concrete continuous beam with externally prestressed CFRP tendons under fatigue loading

2021 ◽  
pp. 136943322199249
Author(s):  
Xing Li ◽  
Jiwen Zhang ◽  
Jun Cheng
Keyword(s):  
Fatigue Life ◽  
Fatigue Loading ◽  
Load Level ◽  
Fiber Reinforced Polymer ◽  
Stiffness Degradation ◽  
Test Results ◽  
Reinforced Polymer ◽  
Continuous Beams ◽  
Practical Engineering ◽  
Good Agreement

This paper presents fatigue behaviors and the stiffness degradation law of concrete continuous beams with external prestressed carbon fiber-reinforced polymer (CFRP) tendons. Three specimens were tested under fatigue loading, and the influence of different load levels on the stiffness degradation and fatigue life were studied, and it was found that the stiffness degradation of three test specimens exhibited a three-stage change rule, namely rapid decrease, stable degradation, and sharp decline, but there are obvious differences in the rate and amplitude of stiffness degradation. The load level has a significant influence on the fatigue life of the test specimens. An analytical model with load level considered was proposed to calculate the residual stiffness and predict the stiffness degradation, which is in good agreement with the test results. The model of stiffness degradation presents a possible solution for practical engineering applications of concrete continuous beams with externally prestressed CFRP tendons subjected to different fatigue loadings.

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