Principles of operation of synchronous machines klempner pdf download

Analyse, and test experimentally, the torque-speed and current-speed characteristics of induction machines. Perform no-load and blocked rotor tests in order to determine the equivalent circuit parameters of an induction machine. Explore various techniques to start an induction motor.

Identify the applications of the three-phase induction machines in industry and utility. Classify the insulations implemented in electrical machines windings and identify the factors affecting them. Investigate the performance, design, operation, and testing of the three-phase synchronous machine. Describe the construction of three-phase synchronous machines, particularly the rotor, stator windings and the rotor saliency.

Develop and manipulate an equivalent circuit model for the three-phase synchronous machine. Sketch the phasor diagram of a non-salient poles synchronous machine operating at various modes operation, such as no-load operation, motor operation, and generator operation. Investigate the influence of the rotor saliency on machine performance.

Perform open and short circuit tests in order to determine the equivalent circuit parameters of a synchronous machine. Identify the applications of the three-phase synchronous machines in industry and utility List and explain the conditions of parallel operation of a group of synchronous generators. Evaluate the performance of the synchronous condenser and describe the power flow control between a synchronous condenser and the utility in both modes: over and under excited.

Explain the principles of controlling the output voltage and frequency of a synchronous generator. An analytical approach to problems concerning electrical machines. Each section relates to one machine, and basic theory is followed by numerical and practical interpretation throughout. Features include coverage of: single-phase machines, and the increasing importance of small machines.

Author : Jan A. This book aims to offer a thorough study and reference textbook on electrical machines and drives. The basic idea is to start from the pure electromagnetic principles to derive the equivalent circuits and steady-state equations of the most common electrical machines in the first parts.

Although the book mainly concentrates on rotating field machines, the first two chapters are devoted to transformers and DC commutator machines. The chapter on transformers is included as an introduction to induction and synchronous machines, their electromagnetics and equivalent circuits. Unknown March 15, at AM.

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This book is not about circuit solutions; therefore the type of load connection will not be brought up herein. In this section three important laws of electromagnetism will be presented.

These laws, together with the law of energy conservation, constitute the basic theoretical bricks on which the operation of any electrical machine can be explained. A moving conductor cutting the lines of force flux of a constant magnetic field has a voltage induced in it. A changing magnetic flux inside a loop made from a conductor material will induce a voltage in the loop. In both instances the rate of change is the critical determinant of the result- ing differential of potential. The figure also shows one of the simple rules that can be used to determine the direction of the induced voltage in the moving conductor.

While Faraday predicts a voltage induced in a conductor moving across a magnetic field, the Ampere-Biot-Savart law establishes that a force is generated on a current- carrying conductor located in a magnetic field. The figure also shows the existing numerical rela- tionships, and a simple hand-rule to determine the direction of the resultant force. Here in a nutshell is the explanation for the generating and motoring modes of operation of an electric rotating machine!

This law explains why when a generator is loaded more current flows in its windings cutting the magnetic field in the gap between rotor and stator , more force is required from the driving turbine to counteract the induced larger forces and keep supplying the larger load.

Basic numerical relationships and a simple rule are used to determine the direction of the induced force. Basic numerical relationships and a simple rule are used to determine the direction of the induced forces and currents. A plus sign indicates energy going in; a minus indicates energy going out. In the case of the stored energy electrical and mechanical , a plus sign indicates an increase of stored energy, while a negative sign indicates a reduction in stored energy.

The balance between the various forms of energy in the machine will determine its efficiency and cooling requirements, both critical performance and construc- tion parameters in a large generator. Therefore it is the right time to introduce the basic configuration of the synchronous machine, which, as mentioned before, is the type of electric machine that all large turbine-driven generators belong to. On that day, the first large-scale demonstration of trans- mission of ac power was carried out.

The transmission extended from Lauffen, Germany, to Frankfurt, about miles away. The demonstration was carried out during an international electrical exhibition in Frankfurt. This demonstration was so convincing about the feasibility of transmitting ac power over long distances, that the city of Frankfurt adopted it for their first power plant, commissioned in This happened about one hundred and eight years before the writing of this book see Fig.

The Niagara Falls power plant became operational in For all practical purposes the great dc versus ac duel was over. Located in San Bernardino County, California, its first units went into operation on September 7, , placing it almost two years ahead of the Niagara Falls project. One of those earlier units is still preserved and displayed at the plant. It is interesting to note that although tremendous development in machine rat- ings, insulation components, and design procedures has occurred now for over one hundred years, the basic constituents of the machine have remained practi- cally unchanged.

The concept that a synchronous generator can be used as a motor followed suit. The world today is divided between countries generating their power at 50 Hz and others e. Additional frequencies e. Synchronous generators have continuously grown in size over the years see Fig. Thus it is not uncommon to see machines with ratings reaching up to MVA, with the largest normally used in nuclear power stations. Interestingly enough, the present ongoing shift from large steam turbines as prime movers to more efficient gas turbines is resulting in a reverse of the trend toward larger and larger gen- erators, at least for the time being.

Transmission system stability considerations also place an upper limit on the rating of a single generator. This section is limited to the presentation of the basic components comprising a synchronous machine, with the purpose of describing its basic operating theory.

Synchronous machines come in all sizes and shapes, from the miniature permanent magnet synchronous motor in wall-clocks, to the largest steam-turbine- driven generators of up to about MVA. Synchronous machines are one of two types: the stationary field or the rotating dc magnetic field.

The stationary field synchronous machine has salient poles mounted on the stator—the stationary member. The poles are magnetized either by permanent magnets or by a dc current.

The armature, normally containing a three-phase winding, is mounted on the shaft. The armature winding is fed through three sliprings collectors and a set of brushes sliding on them. This arrangement can be found in machines up to about 5 kVA in rating. For larger machines—all those covered in this book—the typical arrangement used is the rotating magnetic field.

The rotating magnetic field also known as revolving-field synchronous machine has the field-winding wound on the rotating member the rotor , and the armature wound on the stationary member the stator. A dc current, creating a magnetic field that must be rotated at synchronous speed, energizes the rotating field-winding.

The rotating field winding can be energized through a set of slip rings and brushes external excitation , or from a diode-bridge mounted on the rotor self-excited. The rectifier-bridge is fed from a shaft-mounted alternator, which is itself excited by the pilot exciter. In externally fed fields, the source can be a shaft-driven dc generator, a separately excited dc generator, or a solid-state rectifier.

Several variations to these arrangements exist. The stator core is made of insulated steel laminations. The thickness of the lam- inations and the type of steel are chosen to minimize eddy current and hysteresis losses, while maintaining required effective core length and minimizing costs.

The core is mounted directly onto the frame or in large two-pole machines through spring bars. The core is slotted normally open slots , and the coils making the winding are placed in the slots. There are several types of armature windings, such as concentric windings of several types, cranked coils, split windings of various types, wave windings, and lap windings of various types. Modern large machines typically are wound with double-layer lap windings more about these winding types in Chapter 2.

Non-salient-pole cylindrical rotors are utilized in two- or four-pole machines, and, very seldom, in six-pole machines. These are typically driven by steam or combustion turbines. The vast majority of salient-pole machines have six or more poles. They include all synchronous hydrogenerators, almost every synchronous condenser, and the overwhelming majority of synchronous motors. Non-salient-pole rotors are typically machined out of a solid steel forging.

The winding is placed in slots machined out of the rotor body and retained against the large centrifugal forces by metallic wedges, normally made of aluminum or steel. The retaining rings restrain the end part of the windings end-windings. In the case of large machines, the retaining rings are made out of steel. Large salient-pole rotors are made of laminated poles retaining the winding under the pole head.

The poles are keyed onto the shaft or spider-and-wheel Fig. Schematic cross section of a salient-pole synchronous machine. In a large generator, the rotor is magnetized by a coil wrapped around it. The figure shows a two-pole rotor. Some features of the site may not work correctly. DOI: Klempner , I. Kerszenbaum Published 9 September Engineering Preface. Principles of Operation of Synchronous Machines. Generator Design and Construction.

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