Computational Model for Investigating the Influence of Unbalanced Magnetic Pull on the Radial Vibration of Large Hydro-Turbine Generators

2012 ◽  
Vol 134 (5) ◽  
Author(s):  
Yong Xu ◽  
Zhaohui Li
Keyword(s):  
Computational Model ◽  
Analytical Method ◽  
Analytical Methods ◽  
Electrical Machine ◽  
Radial Vibration ◽  
Turbine Generator ◽  
Hydro Turbine ◽  
Unbalanced Magnetic Pull ◽  
Turbine Generators ◽  
Rotor Model

A radial unbalanced magnetic pull (UMP) can be produced by an eccentric rotor and leads vibrations in large hydro-turbine generators. The influence of nonlinear UMP on the radial vibration of a large hydro-turbine generator is analyzed in this paper. The UMP is determined as a function of eccentricities and field currents by means of a simple analytical method instead of the finite element (FE) method. The analytical method employs the no-load characteristic curve of an electrical machine and saturation effects of the ferromagnetic materials are taken into consideration. FE rotor model of a large hydro-turbine generator unit, taking account of guide bearings, thrust bearing and periodic forces, is developed to investigate the influence of UMP on radial vibrations. The FE rotor model and the analytical method for UMP constitute the computational model. UMP is calculated under different rotor eccentricities and field currents by the proposed method. Comparing with other analytical methods, the effectiveness of the proposed method is verified. Dynamic responses of the FE model under different analytical methods for UMP are calculated to investigate the difference in vibration between different analytical methods. A simulated excitation test is performed and a comparative analysis between the calculated results and the field data is provided. The computational model is proved to be reasonable according to the analysis.

scholarly journals Dynamic Model for Hydro-Turbine Generator Units Based on a Database Method for Guide Bearings

2013 ◽  
Vol 20 (3) ◽  
pp. 411-421 ◽  
Author(s):  
Yong Xu ◽  
Zhaohui Li ◽  
Xide Lai
Keyword(s):  
Dynamic Model ◽  
Power Plants ◽  
Operating Conditions ◽  
Radial Vibration ◽  
Turbine Generator ◽  
Hydro Power ◽  
Rotating Speed ◽  
Hydro Turbine ◽  
Machine Health Monitoring ◽  
Fault Mechanism

A suitable dynamic model of rotor system is of great significance not only for supplying knowledge of the fault mechanism, but also for assisting in machine health monitoring research. Many techniques have been developed for properly modeling the radial vibration of large hydro-turbine generator units. However, an applicable dynamic model has not yet been reported in literature due to the complexity of the boundary conditions and exciting forces. In this paper, a finite element (FE) rotor dynamic model of radial vibration taking account of operating conditions is proposed. A brief and practical database method is employed to model the guide bearing. Taking advantage of the method, rotating speed and bearing clearance can be considered in the model. A novel algorithm, which can take account of both transient and steady-state analysis, is proposed to solve the model. Dynamic response for rotor model of 125 MW hydro-turbine generator units in Gezhouba Power Station is simulated. Field data from Optimal Maintenance Information System for Hydro power plants (HOMIS) are analyzed compared with the simulation. Results illustrate the application value of the model in providing knowledge of the fault mechanism and in failure diagnosis.

Dynamic modeling and vibration response analysis of a synchronous motorized spindle with inclined eccentricity

2021 ◽  
pp. 107754632110233
Author(s):  
Wei Feng ◽  
Kun Zhang ◽  
Baoguo Liu ◽  
Weifang Sun ◽  
Sijie Cai
Keyword(s):  
Analytical Method ◽  
Vibration Response ◽  
Mass Force ◽  
Motorized Spindle ◽  
Dynamic Displacement ◽  
Unbalanced Mass ◽  
Unbalanced Magnetic Pull ◽  
Spindle Bearing ◽  
Mass Eccentricity ◽  
Bearing System

The air-gap eccentricity will produce unbalanced magnetic pull and cause vibrations and noises in a motor. In this study, the dynamic behavior of a synchronous motorized spindle with inclined eccentricity is investigated. A semi-analytical method is proposed to model the unbalanced magnetic pull and the electromagnetic torque of a rotor with inclined eccentricity, and the semi-analytical method is verified by the finite element method. The dynamic model of a spindle-bearing system is built by taking the centrifugal force and gyroscopic effects into account. Then, the vibration response of dynamic displacement eccentricity, inclined eccentricity including displacement eccentricity and angle eccentricity, rotating speed, and unbalanced mass eccentricity in both time domain and frequency domain are simulated and analyzed. The results show that the eccentricities can lead to fluctuations in amplitudes of the dynamic displacement response and the angle response. The frequency components of the dynamic responses are the combination of rotating frequency, VC frequency, and power frequency. It is indicated that the coupling interactions of bearing forces, unbalanced mass force, and unbalanced magnetic pull have an obvious effect on the spindle-bearing system.

Developments in mycotoxin analysis: an update for 2010-2011

2012 ◽  
Vol 5 (1) ◽  
pp. 3-30 ◽  
Author(s):  
G. Shephard ◽  
F. Berthiller ◽  
P. Burdaspal ◽  
C. Crews ◽  
M. Jonker ◽  
...  
Keyword(s):  
Analytical Method ◽  
Analytical Methods ◽  
Method Development ◽  
Rapid Development ◽  
Ergot Alkaloids ◽  
Alternaria Toxins ◽  
Research Publications ◽  
Mycotoxin Analysis ◽  
The Subject ◽  
Conventional Methods

This review highlights developments in mycotoxin analysis and sampling over a period between mid-2010 and mid-2011. It covers the major mycotoxins: aflatoxins, Alternaria toxins, ergot alkaloids, fumonisins, ochratoxin, patulin, trichothecenes, and zearalenone. Analytical methods for mycotoxins continue to be developed and published. Despite much interest in immunochemical methods and in the rapid development of LC-MS methodology, more conventional methods, sometimes linked to novel clean-up protocols, have also been the subject of research publications over the above period. Occurrence of mycotoxins falls outside the main focus of this review; however, where relevant to analytical method development, this has been mentioned.

A Review: Method Development Validation and Degradation Studies of some Anticancer Drugs

2021 ◽  
pp. 5443-5448
Author(s):  
Punna Venkateshwarlu ◽  
Mehul M. Patel
Keyword(s):  
Liquid Chromatography ◽  
Anticancer Drugs ◽  
Analytical Method ◽  
Analytical Methods ◽  
Bioanalytical Methods ◽  
Method Development ◽  
Estimation Methods ◽  
Simultaneous Estimation ◽  
Pharmaceutical Dosage Forms ◽  
Stability Indicating

This article reviews the various analytical methods reported so far in the literature for the determination of stability and impurity profile the lenalidomide and palbociclib anti cancer drugs in single or combination with other drugs in bulk, pharmaceutical dosage forms, biological fluids, stability indicating and impurity profiling methods. The analytical methods used for the estimation of lenalidomide and palbociclib anticancer drugs reviewed in this paper includes ultraviolet spectrophotometry,high performance liquid chromatography (HPLC) ,ultra performance liquid chromatography (UPLC) ,liquid chromatography-mass spectrometry (LC-MS) and electrophoresis. This review focus on the effect of all chromatographic parameters so as to provide as fast, reliable and cost effective methodology of testing. Method development is the process of proving that analytical method is acceptable for use to measure the concentration of active pharmaceutical ingredient in a specific compound dosage form which must be validated to provide reliable data for regulatory submissions. This reviewed is mainly on analytical method development and validation, stability indicating methods, simultaneous estimation methods and bioanalytical methods. The review covers the time period from 2007 to 2019 during which analytical methods including all types of spectrophotometric and chromatographic techniques were reported. The Review covers lenalidomide and palbociclib API and formulation analytical and bioanalytical methods.

Sir Charles Parsons and Electrical Power Generation—a Turbine Designer's Perspective

1994 ◽  
Vol 208 (3) ◽  
pp. 159-176 ◽  
Author(s):  
J R Bolter
Keyword(s):  
Power Generation ◽  
Steam Turbine ◽  
Gas Turbine ◽  
Electrical Power Generation ◽  
Analytical Methods ◽  
State Of The Art ◽  
Electrical Power ◽  
Turbine Generator ◽  
Current State ◽  
The World

Sir Charles Parsons died some three years after the author was born. In this paper the author looks back at the pioneering work of Parsons in the field of power generation. It shows how he was able to increase output of the steam turbine generator from 7.5 kW in 1884 to 50000 kW in 1930 while increasing efficiency from 1.6 to 36 per cent, and relates these achievements to the current state of the art. Blading design, rotor construction and other aspects of turbine engineering are considered. The conclusion is that Parsons and his associates charted the course which manufacturers and utilities throughout the world have continued to follow, although increasingly sophisticated design and analytical methods have succeeded the intuitive approach of Parsons. His constant search for improved efficiency was and is highly relevant to today's concern for the environment. Finally, although it did not become a practical proposition in his lifetime, the paper reviews Parsons' vision of, and continuing interest in, the gas turbine, first mentioned in his 1884 patents.

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