This chapter include contents: Introduction to Polyphase Induction Machines, currents and fluxes in Polyphase Induction Machines, induction – motor equivalent circuit, analysis of the equivalent circuit, torque and power by use of Thevenin’s theorem, parameter determination from no – load and blocked – rotor tests, effects of rotor resistance.
Introduction to AC machine, synchronous generators, synchronous motors, three phase Induction machines, three phase induction motors, induction generators, induction regulators As the main contents of the document "Electrical machines 2". Invite you to consult the text book for more documents serving the academic needs and research.
Construction and operating principles of induction motors are presented in this chapter. The generation of a revolving magnetic field in the stator and torque production in the rotor are described. The per-phase equivalent circuit is introduced for determination of steady-state characteristics of the motor. Operation of the induction machine as a generator is explained.
The purpose of these notes is be used to introduce Electrical Engineering students to Electrical
Machines, Power Electronics and Electrical Drives. They are primarily to serve our students at
MSU: they come to the course on Energy Conversion and Power Electronics with a solid background
in Electric Circuits and Electromagnetics, and many want to acquire a basic working knowledge
of the material, but plan a career in a different area (venturing as far as computer or mechanical
Motivated by the need of energy-efficiency improvements, process optimization, soft-start capability and numerous other environmental benefits, it may be desirable to operate induction motors for many applications at continuously adjustable speeds. The induction motor drives can provide high productivity with energy efficiency in different industrial applications and are the basis for modern automation. This book provides an account of this developing subject through such topics as modelling, noise, control techniques used for high-performance applications and diagnostics....
(BQ) he objective of Ebook Electrical machine is to study the devices used in the interconversion of electric and mechanical energy. Emphasis is placed on electromagnetic t rotating machinery, by means of which the bulk of this energy conversion takes place.
Flux and Voltage Induction Machines 6.1 Description 6.2 Concept of Operation 6.3 Torque Development 6.4 Operation of the Induction Machine near Synchronous Speed 6.5 Leakage Inductances and their Effects 6.6 Operating characteristics 6.7 Starting of Induction Motors 6.8 Multiple pole pairs Synchronous Machines and Drives 7.1 Design and Principle of Operation 7.1.1 Wound Rotor Carrying DC 7.1.2 Permanent Magnet Rotor 7.2 Equivalent Circuit 7.3 Operation of the Machine Connected to a Bus of Constant Voltage and Frequency 7.4 Operation from a Source of Variable Frequency and Voltage...
Aims doctoral thesis: The application of doubly - fed induction machine on power-station on shipboard ensures that the two work modes working in parallel with the grid of shipboard and work independently when requiring.
Electric machines have dangerous live and rotaling parts and may hot surfaces. All operations serving transport, storage, installation, connection, commissioning. operation and mailntenance shall be canied uot by responsible skilled persons.
The use of a combustion engine to motivate a car has been questioned in recent times due
to the increasing concern of warming. As a result of this, the concept of driving
a car with an electric engine has become of particular interest. Dr. Geoff Walker and his
PhD students are working on the creation of the Universitys own electric car.
This thesis project is focused on deriving a control scheme to drive an induction machine
that could be applied to the electric car.
Consider an electric machine with six windings. Stator and rotor are of cylindrical cross-section and three windings are situated on stator while the remaining three windings are on the rotor, as shown in Fig. 1. Both stator and rotor windings are displaced in space for 120 degrees electrical. In this electromechanical converter a continual electromechanical energy conversion may take place provided that, if angular frequency of stator currents is ωs and angular frequency of rotor currents is ωr, rotor speed is ω = ω s − ω r .
The speed of the rotating magnetic field 2πf1 ωsyn = P/2 60f1 nsyn = P/2 (rad/s) (rev/min)
where f1 is the frequency of the stator current, and P the number of poles. 2. The rotor speed of an induction machine is generally different from the speed of the rotating magnetic field. The percentage difference of speed, known as slip, is defined as s= ωsyn-ωm nsyn-n = n ωsyn syn
where ωm and n are the speed of the rotor in rad/s and rev/min, respectively. 3. The induced emf in one phase of the stator winding is E1 = 4.44f1N1kw1Φm and...
Electric Drives Ion Boldea and Syed Nasar Linear Synchronous Motors: Transportation and Automation Systems Jacek Gieras and Jerry Piech Electromechanical Systems, Electric Machines, and Applied Mechatronics Sergey E. Lyshevski Electrical Energy Systems Mohamed E. El-Hawary Distribution System Modeling and Analysis William H. Kersting The Induction Machine Handbook Ion Boldea and Syed Nasar Power Quality C. Sankaran Power System Operations and Electricity Markets Fred I. Denny and David E.
The dominant practice of statistical machine translation (SMT) uses the same Chinese word segmentation specification in both alignment and translation rule induction steps in building Chinese-English SMT system, which may suffer from a suboptimal problem that word segmentation better for alignment is not necessarily better for translation.
In this work we propose methods to label probabilistic synchronous context-free grammar (PSCFG) rules using only word tags, generated by either part-of-speech analysis or unsupervised word class induction. The proposals range from simple tag-combination schemes to a phrase clustering model that can incorporate an arbitrary number of features. Our models improve translation quality over the single generic label approach of Chiang (2005) and perform on par with the syntactically motivated approach from Zollmann and Venugopal (2006) on the NIST large Chineseto-English translation task. ...
This paper extends the training and tuning regime for phrase-based statistical machine translation to obtain ﬂuent translations into morphologically complex languages (we build an English to Finnish translation system). Our methods use unsupervised morphology induction. Unlike previous work we focus on morphologically productive phrase pairs – our decoder can combine morphemes across phrase boundaries. Morphemes in the target language may not have a corresponding morpheme or word in the source language.
This paper reports a pilot study, in which Constraint G r a m m a r inspired rules were learnt using the Progol machine-learning system. Rules discarding faulty readings of ambiguously tagged words were learnt for the part of speech tags of the Stockholm-Ume£ Corpus. Several thousand disambiguation rules were induced. When tested on unseen data, 98% of the words retained the correct reading after tagging. However, there were ambiguities pending after tagging, on an average 1.13 tags per word.
We estimate the parameters of a phrasebased statistical machine translation system from monolingual corpora instead of a bilingual parallel corpus. We extend existing research on bilingual lexicon induction to estimate both lexical and phrasal translation probabilities for MT-scale phrasetables. We propose a novel algorithm to estimate reordering probabilities from monolingual data. We report translation results for an end-to-end translation system using these monolingual features alone.
Chinese abbreviations are widely used in modern Chinese texts. Compared with English abbreviations (which are mostly acronyms and truncations), the formation of Chinese abbreviations is much more complex. Due to the richness of Chinese abbreviations, many of them may not appear in available parallel corpora, in which case current machine translation systems simply treat them as unknown words and leave them untranslated.
This chapter include all of the following content: Introduction to polyphase synchronous machines, synchronous – machine inductances and equivalent circuits, performance characteristics, effects of salient poles, power – angle characteristics of salient – pole machines, permanent – magnet ac motors.