The synchronous electrical generator also called alternator belongs to the family of electric rotating machines. The prime movers used for salient pole alternators are water wheels like kaplan turbine, francis turbine, pelton wheel. The field coils may be on the stator or on the rotor. There are mainly two types of rotors used in construction of alternator. The magnitude of this change depends not only on the load but also on the load power factor the voltage regulation of an alternator is defined as the rise in voltage when fullload is removed field excitation and speed remaining the same divided by the rated. Figure shows the complete phasor diagram for the mmf. The shaft and pole bodies are of integral construction, produced from a single normalized carbon steel forging. Regulations on 3phase salient pole alternator by slip test. Electricityconnect connect is the community of production, distribution and transmission of electricity. The developed torque versus torque angle for a salientpole synchronous generator. No load and blocked rotor test on 3phase induction motor. With connecting society and experts, this free platform aims to facilitate sharing of knowledge and improve notoriety of your company on the web. In case of salient pole machines regulation is found out by applying blondels two reaction theory.
The magnetic path is characterized by poles, locations at equal angles around the rotor at which the magnetic field lines pass from stator to rotor or vice versa. The alternator is also responsible for charging the battery when the car is running. Voltage regulation by emf method, mmf method, and zpf method tutorial 6 quiz 2. Short questions and answers ee1251 electrical machines ii 1. The rotor winding is provided on these poles and it is supported by pole shoes. Analysis of non salient pole synchronous generator using. On the theory of salient pole alternators with electromagnet. Ee6504 electrical machines 2 question bank regulation 20. Solid salient pole motor synchronousmotor ge power. What are the advantages of a round rotor generator than a salient pole rotor. The proposed smpi voltage regulator has been evaluated experimentally by using a laboratory setup whose structure was presented in fig. Determine a the armature current of the second alternator, and b the power factor at which each machine operates. The synchronous generator is connected to a threephase. Synchronizing method, effect of wrong synchronizing, load sharing between alternators in parallel.
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. Why almost all large size synchronous machines are constructed with. If there are any issues with the alternator, it also affects the functioning of the ignition system, headlights, air conditioning. Now, with this background, let us discuss principle first. What are the advantages of salient pole type construction used for synchronous machines. Lecture notes on electrical machinesii the induced torque out of a salientpole generator as a function of the torque angle. They are called the turbinedriven and salientpole rotors. Ppt alternator powerpoint presentation free to view. Analysis of non salient pole synchronous generator characteristics using phasor diagrams yahaya a. 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. The salient pole type of rotor is generally used for slow speed machines having large diameters and relatively small axial lengths. Cylindrical rotor alternators are usually long, and the problem of air f low requires very special attention. What are the advantages of a round rotor generator than a.
Apply 2 12 the stator of a 3phase, 24 pole alternator has 120 slots and there are 4 conductors per slot accommodated in two layers. Assignment discussion 2 expressions for power input and power output, power angle characteristics. They are called the turbinedriven and salient pole rotors. The open circuit voltage and short circuit current of a 3 phase, star connected alternator are 1050 v and 250 a respectively. Blondels two reaction theory, phasor diagram, direct axis and quadrature axis synchronous reactances, power angle characteristics, slip test. Due to this the mmfs of armature and field act upon the same magnetic circuit all the time hence can be added vectorically. V and inverted v curves of 3 phase synchronous motor.
Equivalent circuit of single phase induction motor 8. Nonsalient pole the salient pole is most commonly used configuration. In this method also it is assumed that the magnetic circuit is unsaturated. The aim of the experiment is to predetermine the regulation of three phase salient pole alternator by conducting the slip test. It contains everything needed for salient pole generator experiments including resistive, capacitive and inductive load banks. The stator and rotor are classified by the number of poles they have.
Voltage regulation of a synchronous generator direct. What are the prime movers used for a salient pole b non salient pole alternator. How winding is done in the salient type rotor of alternator. In non salient pole alternators air gap length is constant and reactance is also constant. Why salient pole synchronous machine are more stable than. Construction of a synchronous machine circuit globe. It is clear that with change in load, there is a change in terminal voltage of an alternator. The magnitude of this change depends not only on the load but also on the load power factor. There are mainly two types of synchronous generator from rotor construction point of view. A 3phase, 8pole, 750 rpm star connected alternator has 72 slots on the.
Mar 04, 2020 there are mainly two types of rotors used in construction of alternator. Oct 26, 2016 yes, i would like to resolve this too. Electrical machines iii electrical and electronics engineering time. It is a dynamo which can converts the mechanical energy of the crankshaft into electrical energy to store in the car battery. Designed, built and tested in the motor factory, solid salient pole rotors are suitable for applications requiring long duty cycles. Be semestervith electrical question bank electrical. What is the difference between a salient pole and a. Manipal institute of technology manipal university. Jun 04, 2015 voltage regulation it is clear that with change in load, there is a change in terminal voltage of an alternator.
How is the regulation of alternator predetermined by slip test. Construction of a synchronous machine construction of a synchronous machine, i. The field excitation of the first machine is adjusted so that the armature current is 50a. But in salient pole alternators the length of the air gap varies and reluctance also varies. A 6ploe, 50hz starconnected alternator has a flux per pole of 0. Since the regulation of an alternator depends on the load and the load power factor, it is necessary to mention power factor while expressing regulation. What do you mean by single layer and double layer winding.
The two main types of synchronous machine are cylindrical rotor and salient pole. May 05, 2014 voltage induced for a flux per pole of 0. Why salient pole synchronous machine are more stable than the. Apply 2 12 the stator of a 3phase, 24pole alternator has 120 slots and there are 4 conductors per slot accommodated in two layers. Analysis of nonsalient pole synchronous generator using. Regulation of 3phase alternator by zpf and asa methods. Regulation of 3phase alternator by emf and mmf methods. What is the difference between salient pole alternator and cylindrical rotor type alternator. Analysis of nonsalient pole synchronous generator characteristics using phasor diagrams yahaya a. Reactance voltage drop will be less and the voltage regulation will be better.
Jul 15, 2016 the rotor of alternator is designed in either of the two configurations. A graphical method has been developed for rapidly determining from two reactances the regulation of alternators for a wide range of power factor. In this method both the reactance drops are replaced by their equivalent mmfs. This is because the field winding is always concentrated on a pole core while the armature winding is always distributed. The equation for the induced voltage on a moving conductor in the presence of a magnetic field is. Ee8401 question paper electrical machines 2 regulation 2017.
Short questions and answers ee1251 electrical machines ii. Alternator rotors there are two types of rotors used in rotatingfield alternators. Now if the speed of the alternator is reduced to 750 rpm but the field current remains unchanged, the load current will become. The cooling medium, air or hydrogen is cooled by passing over pipes through which cooling water is circulated and ventilation of the alternator. Example 12 a 12pole, 3phase, starconnected alternator has 72 slots. Dhanalakshmi srinivasan institute of technology, samayapuram, trichy. Ppt alternator powerpoint presentation free to view id. The voltage regulation of an alternator is defined as the change in terminal voltage from noload to load condition expressed as a fraction or percentage.
Compare the salient pole rotor and cylindrical pole rotor on stability point. Many vital systems of your car are also dependent on the alternator for their functioning. Alternator and poles electronics forum circuits, projects. It has 6 slots per pole per phase, conductors per slot being 4. As you may have guessed, the turbinedriven rotor shown in figure 34, view a, is used when the.
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. The rotor of alternator is designed in either of the two configurations. Reactance voltage drop will be less and the voltage regulation will. Explain the constructional details of alternator in. Then the synchronous impedance of alternator will be a. Large scr result in a good regulation, good stability and large i sc 7. The following are the principal advantages of the rotating field system type construction of synchronous machines. Other members of the family are the directcurrent dc motor or generator, the induction motor or generator, and a number of derivatives of all these three.
Two reaction theory of salient pole synchronous alternator. Voltage regulation of alternator and solved example youtube. Apply 1 12 the stator of a 3phase, 24pole alternator has 120 slots and there are 4 conductors per slot accommodated in two layers. Blondels two reaction theory, modelling direct and quadrature axis reactance, phasor diagram. Salient pole machines have more diameter and less axial length. Consequently the methods for finding out the regulation of cylindrical rotor machines when applied to salient pole machines give results which are not correct. The motor field rheostat should be kept in minimum resistance position.
Alternator on load synchronous reactance vector diagrams of loaded alternator voltage regulation rotherts m. This rotor has solid poles and a striponedge field winding. Warning signs of a failing alternator the alternator is a part of the electrical system of your car which is generally responsible for powering the car accessories. The projected poles are made up from laminations of steel. Determination of xd and xq of salient pole synchronous machine in addition to the above eight experiments, at least any two of the following. Salient pole generator description the salient pole generator explores the principles and characteristics of salient pole generators. Voltage regulation of a synchronous generator the voltage regulation of a synchronous generator is the rise in voltage at the terminals when the load is reduced from full load rated value to zero, speed and field current remaining constant. Example 12 a 12 pole, 3phase, starconnected alternator has 72 slots. In salient pole type of rotor consist of large number of projected poles salient poles mounted on a magnetic wheel.
Non salient pole the salient pole is most commonly used configuration. The voltage regulation of an alternator is defined as the rise in voltage when fullload is removed. It carries the armature winding in which the voltage is generated. Regulation in a voltage source, be it a power supply or an alternator or transformer or even a battery, is the change in output voltage over its full range of load current. To conduct the slip test on three phase alternator and predetermination the regulation through vector diagrams apparatus required precaution 1. Ademoh 2 using various theories and equations derived from possible phasor diagrams of the generator. An alternator is supplying 10a to an inductive load at 220 v, while running at rpm. Construction of a salient pole rotor is as shown in the figure at left. The prime movers used for salient pole alternators are water wheels like kaplan turbine, francis turbine, pelton wheel etc. Why almost all large size synchronous machines are constructed with rotating field system type. Voltage regulation characteristics of a synchronous generator.