What are the advantages of salient pole type construction. Its intensity and direction determine the forces of attraction or repulsion existing between the two magnets. Most synchronous generator or alternators have rotating field and stationary armature. It is also known as operating charts or capability charts. Methods of finding voltage regulation in synchronous generator. It is a test done in alternator to measure the value of direct axis synchronous reactancexd and quadrature axis synchronous reactancexq. Also calculate the regulation if the same alternator is loaded to rated current at 0. In salient pole type of rotor consist of large number of projected poles salient poles mounted on a magnetic wheel. Why the bmw alternator is failed to charge there are certain components in your bmw that play a crucial role in the smooth running and better performance of the car. Directaxis and quadratureaxis synchronous reactances. Blondel two reaction theory salient pole alternators theory. The two main types of synchronous machine are cylindrical rotor and salient pole. A 6ploe, 50hz starconnected alternator has a flux per pole of 0.
The projected poles are made up from laminations of steel. Similar to the case of dc generator, the behaviour of a synchronous generator connected to an external load is different than that at noload. The shaft and pole bodies are of integral construction, produced from a single normalized carbon steel forging. The non salient pole types are used for high speed alternators called turbo alternators with speeds ranging from 1500 to 3000 r.
Blondels two reaction theory, phasor diagram, direct axis and quadrature axis synchronous reactances, power angle characteristics, slip. To find xd and xq of a salient pole rotor type synchronous machine by slip test apparatus. D7escribe a method of determining direct and quadrature axis reactance of salient pole alternator. The rotor is a moving component of an electromagnetic system in the electric motor, electric generator, or alternator. Synchronous machines notes part2 electric equipment. Alternator generator mcqs with explanatory answers. The prime movers used for salient pole alternators are water wheels like kaplan turbine, francis turbine, pelton wheel etc. Around each of the rotors laminated salient poles are directionally wound coils.
Large scr result in a good regulation, good stability and large i sc 7. Regulation in a generator indicates how the terminal voltage of the machine. Salient pole alternators and blondels two reaction theory. Synchronous machines notes introduction synchronous machines are principally used as alternating current generators. There are mainly two types of synchronous generator from rotor construction point of view. Salient pole machine, or effect of salient poles, or two reaction theory 2. Pdf this thesis includes the redesign and construction details of a salient pole rotor for an existing aircraft alternator.
Salient pole machines have more diameter and less axial length. There are some disturbing factors in salient pole alternators which are analysed below. Phasor diagrams regulation of salient pole alternators. The theory which gives the method of analysis of the disturbing effects caused by salient pole construction is called two reaction theory. It has a large number of projecting salient poles, having their cores bolted or dovetailed onto a heavy magnetic wheel of castiron, or steel of good magnetic quality fig. Capability curve of a synchronous generator circuit globe. Explain the constructional details of alternator in. Nonsalient or cylindrical pole type salient pole type. Salientpole rotors may be used in alternators driven by what types of prime. The rotor winding is provided on these poles and it is supported by pole. Synchronising method, effect of wrong synchronising, load sharing between alternators in parallel. Solid salient pole motor synchronousmotor ge power. However, north and south poles always attract each other.
Apply 2 12 the stator of a 3phase, 24 pole alternator has 120 slots and there are. Determination of x d and x q direct axis and quadrature axis reactances 4. To pre determine the regulation of an alternator at full load at different power factors. Ventilation or cooling of an alternator the slow speed salient pole alternators are ventilated by the fan action of the salient poles which provide circulating air. The power output of a synchronous generator is the sum of the power due to the directaxis current d and the power due to the quadratureaxis current. Novdec 2016 salient pole types are used for low speed alternators with speeds ranging from 125 to 500 r. Ee8401 question paper electrical machines 2 regulation 2017. The details of synchronous generators developed so far is applicable to only round rotor or non salient pole alternators. Cylindrical rotor alternators are usually long, and the problem of air f low requires very special attention.
For the slip test, the alternator should be driven at a speed, slightly less than the. Now, with this background, let us discuss principle first. Pdf analysis of nonsalient pole synchronous generator using. The phasor diagram of a salientpole synchronous generator.
Power equation derivation of a salient pole synchronous machine. The electrical machines 3 notes pdf em iii notes pdf book starts with the topics covering constructional features of round rotor and salient pole machines, suppression of harmonics, regulation by synchronous impedance method, parallel operation of synchronous generator synchronizing alternators with infinite bus bars, theory of operation. The individual field pole windings are connected in series in such a way that when the field winding is energized by the d. Ig is the ignition input that turns on the alternator regulator assembly. There are mainly two types of rotors used in construction of alternator. Salient pole generator description the salient pole generator explores the principles and characteristics of salient pole generators. Blondels two reaction theory, phasor diagram, direct axis and quadrature axis synchronous reactances, power angle characteristics, slip test.
Parallel operation of two alternators mcqs with answers. As it will be shown later, alternators operate with both alternating ac and directcurrent dc electric power. It contains everything needed for salient pole generator experiments including resistive, capacitive and inductive load banks. Regulation of alternator at full load is found to be. Salient pole type rotors are designed for alternators with many number of poles and cylindrical rotors are designed for alternators with. Now let us discuss about construction of alternator or synchronous machine. In such machines the air gap is uniform throughout and hence the effect of mmf will be same whether it acts along the pole axis or the inter polar axis. Thus a salient pole rotor consists of poles projecting out from the.
Voltage regulation of alternator emf and mmf methods duration. This rotor has solid poles and a striponedge field winding. Ppt alternator powerpoint presentation free to view. In order to derive various conditions for power in both alternators and synchronous motors, let us consider the general problem of. Power angle characteristic of salient pole machine. The dc can be considered a particular case of the general ac, with frequency equal to zero. Lecture notes on electrical machinesii the induced torque out of a salientpole generator as a function of the torque angle. One such system is the alternator which is used for generating the electricity for its electrical components as well as responsible for maintaining its battery charge. Sm28 two reaction theory of salient pole alternator. What is the difference between a salient pole and a. The synchronous electrical generator also called alternator belongs to the. A brushless exciter model incorporating multiple rectifier modes.
This method requires following data to calculate the regulation. No name of experiment page no 1 to perform the brake test on a 3 slip ring induction motor and obtain its performance characteristics 2 to start a 3phase slip ring induction motor by rotor resistance starter. Synchronizing alternators with infinite bus bars synchronizing power torque parallel operation and load sharing effect of change of excitation and mechanical power input. Apply 1 12 the stator of a 3phase, 24 pole alternator has 120 slots and there are 4 conductors per slot accommodated in two layers. Voltage regulation is controlled by a solid state electronic analogue automatic voltage. In situ parameter estimation of synchronous machines using. Two north poles always repel each other, as do two south poles. The cooling medium, air or hydrogen is cooled by passing over pipes through which cooling water is circulated and ventilation of the alternator. It has 6 slots per pole per phase, conductors per slot being 4. S is used by the regulator to monitor charging voltage at the battery. Salient pole synchronous motor power developed by a salient pole synchronous motor effects of excitation on armature current and power factor. The permissible region of operation is restricted to the following points given below. Construction of alternator synchronous generator mcqs.
This paper sets to present the dynamic model and simulation of a threephase salient pole. Blondels two reaction theory salient pole machine theory. It is done only on salient pole alternators non uniform field. In generators and alternators, the rotor designs are salient pole or cylindrical. For further reading there is a library of documents in a specific section.
In this type, salient or projecting poles are mounted on a large circular steel frame which is fixed to the shaft of the alternator as shown in fig. What are the advantages of salient pole type construction used for synchronous machines. Understanding the alternator four wires connect the alternator to the rest of the charging system. Phasor diagram of salient pole synchronous machine for generator and motor mode duration. Non salient or cylindrical pole type salient pole type.
For voltage regulation, the angle of vt is first considered to be zero so that the. B is the alternator output wire that supplies current to the battery. A graphical method has been developed for rapidly determining from two reactances the regulation of alternators for a wide range of power factor. Why salient pole synchronous machine are more stable than. Franklin, theory of the three phase salient pole type generator. The developed torque versus torque angle for a salientpole synchronous generator. Salientpole machines have an additional winding in the rotating mem ber. Capability curve of a synchronous generator the capability curve of a synchronous generator defines a boundary within which the machine can operate safely. Designed, built and tested in the motor factory, solid salient pole rotors are suitable for applications requiring long duty cycles. In fact, a given synchronous machine may be used, at least theoretically, as an alternator, when driven.
Derivation of various power conditions in alternators and. Construction of a salient pole rotor is as shown in the figure at left. Procedure of synchroniation a dark lamp method b synchroscope c computerized synchronisation 6. How does electrical degree differ from mechanical degree. Dynamic modelling and simulation of salient pole synchronous motor using embedded matlab onah, c. What are the prime movers used for a salient pole b non salient pole alternator. Base values, transformation ratio, and rotor parameters referred to the stator.
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