The voltage regulation of an alternator is defined as the rise in voltage when fullload is removed. With connecting society and experts, this free platform aims to facilitate sharing of knowledge and improve notoriety of your company on the web. There are mainly two types of rotors used in construction of alternator. The synchronous electrical generator also called alternator belongs to the family of electric rotating machines. Example 12 a 12pole, 3phase, starconnected alternator has 72 slots.
It is a dynamo which can converts the mechanical energy of the crankshaft into electrical energy to store in the car battery. Cylindrical rotor alternators are usually long, and the problem of air f low requires very special attention. Voltage regulation of alternator and solved example youtube. 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. Lecture notes on electrical machinesii the induced torque out of a salientpole generator as a function of the torque angle. What do you mean by single layer and double layer winding. A 6ploe, 50hz starconnected alternator has a flux per pole of 0. The equation for the induced voltage on a moving conductor in the presence of a magnetic field is. How winding is done in the salient type rotor of alternator. But in salient pole alternators the length of the air gap varies and reluctance also varies. The alternator is also responsible for charging the battery when the car is running. Due to this the mmfs of armature and field act upon the same magnetic circuit all the time hence can be added vectorically. Compare the salient pole rotor and cylindrical pole rotor on stability point.
Ademoh 2 using various theories and equations derived from possible phasor diagrams of the generator. Determine a the armature current of the second alternator, and b the power factor at which each machine operates. Many vital systems of your car are also dependent on the alternator for their functioning. 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. Analysis of non salient pole synchronous generator using. V and inverted v curves of 3 phase synchronous motor. Designed, built and tested in the motor factory, solid salient pole rotors are suitable for applications requiring long duty cycles. Assignment discussion 2 expressions for power input and power output, power angle characteristics. They are called the turbinedriven and salient pole rotors. The aim of the experiment is to predetermine the regulation of three phase salient pole alternator by conducting the slip test. The prime movers used for salient pole alternators are water wheels like kaplan turbine, francis turbine, pelton wheel. Why almost all large size synchronous machines are constructed with. D7escribe a method of determining direct and quadrature axis reactance of salient pole alternator.
The open circuit voltage and short circuit current of a 3 phase, star connected alternator are 1050 v and 250 a respectively. Short questions and answers ee1251 electrical machines ii. The rotor of alternator is designed in either of the two configurations. 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. It contains everything needed for salient pole generator experiments including resistive, capacitive and inductive load banks. Analysis of non salient pole synchronous generator characteristics using phasor diagrams yahaya a. Figure shows the complete phasor diagram for the mmf. The stator and rotor are classified by the number of poles they have. Voltage regulation by emf method, mmf method, and zpf method tutorial 6 quiz 2. Apply 2 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, phasor diagram, direct axis and quadrature axis synchronous reactances, power angle characteristics, slip test. Construction of a synchronous machine circuit globe.
The prime movers used for salient pole alternators are water wheels like kaplan turbine, francis turbine, pelton wheel etc. 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. Large scr result in a good regulation, good stability and large i sc 7. How is the regulation of alternator predetermined by slip test.
Now, with this background, let us discuss principle first. 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. Describe with neat sketch, the constructional details of salient pole alternators. An alternator is supplying 10a to an inductive load at 220 v, while running at rpm. The following are the principal advantages of the rotating field system type construction of synchronous machines. Why salient pole synchronous machine are more stable than. Synchronizing method, effect of wrong synchronizing, load sharing between alternators in parallel. The field coils may be on the stator or on the rotor.
To conduct the slip test on three phase alternator and predetermination the regulation through vector diagrams apparatus required precaution 1. The two main types of synchronous machine are cylindrical rotor and salient pole. Ee8401 question paper electrical machines 2 regulation 2017. It carries the armature winding in which the voltage is generated. Ppt alternator powerpoint presentation free to view id. Electricityconnect connect is the community of production, distribution and transmission of electricity. Analysis of nonsalient pole synchronous generator characteristics using phasor diagrams yahaya a. Analysis of nonsalient pole synchronous generator using. If there are any issues with the alternator, it also affects the functioning of the ignition system, headlights, air conditioning. In non salient pole alternators air gap length is constant and reactance is also constant.
Voltage regulation characteristics of a synchronous generator. The cooling medium, air or hydrogen is cooled by passing over pipes through which cooling water is circulated and ventilation of the alternator. The alternator field should be kept open throughout the experiment. It is clear that with change in load, there is a change in terminal voltage of an alternator. Alternator rotors there are two types of rotors used in rotatingfield alternators. The developed torque versus torque angle for a salientpole synchronous generator. Regulation of 3phase alternator by zpf and asa methods.
Non salient pole the salient pole is most commonly used configuration. This is because the field winding is always concentrated on a pole core while the armature winding is always distributed. In this method also it is assumed that the magnetic circuit is unsaturated. They are called the turbinedriven and salientpole rotors. Dhanalakshmi srinivasan institute of technology, samayapuram, trichy. Reactance voltage drop will be less and the voltage regulation will be better. Oct 26, 2016 yes, i would like to resolve this too. Then the synchronous impedance of alternator will be a. Reactance voltage drop will be less and the voltage regulation will. 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. 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. The proposed smpi voltage regulator has been evaluated experimentally by using a laboratory setup whose structure was presented in fig. 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.
Two reaction theory of salient pole synchronous alternator. This rotor has solid poles and a striponedge field winding. Why almost all large size synchronous machines are constructed with rotating field system type. Solid salient pole motor synchronousmotor ge power. In salient pole type of rotor consist of large number of projected poles salient poles mounted on a magnetic wheel. 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. As you may have guessed, the turbinedriven rotor shown in figure 34, view a, is used when the. The rotor winding is provided on these poles and it is supported by pole shoes.
Mar 04, 2020 there are mainly two types of rotors used in construction of alternator. Short questions and answers ee1251 electrical machines ii 1. 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. The shaft and pole bodies are of integral construction, produced from a single normalized carbon steel forging.
Voltage regulation of a synchronous generator direct. 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 projected poles are made up from laminations of steel. What are the advantages of a round rotor generator than a salient pole rotor. Salient pole machines have more diameter and less axial length.
Equivalent circuit of single phase induction motor 8. May 05, 2014 voltage induced for a flux per pole of 0. Blondels two reaction theory, modelling direct and quadrature axis reactance, phasor diagram. A 3phase, 8pole, 750 rpm star connected alternator has 72 slots on the. What are the prime movers used for a salient pole b non salient pole alternator. 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. What are the advantages of salient pole type construction used for synchronous machines. Regulation of 3phase alternator by emf and mmf methods. The field excitation of the first machine is adjusted so that the armature current is 50a. Determination of xd and xq of salient pole synchronous machine in addition to the above eight experiments, at least any two of the following. What is the difference between salient pole alternator and cylindrical rotor type alternator. Apply 1 12 the stator of a 3phase, 24pole alternator has 120 slots and there are 4 conductors per slot accommodated in two layers. Alternator and poles electronics forum circuits, projects.
Alternator on load synchronous reactance vector diagrams of loaded alternator voltage regulation rotherts m. Construction of a synchronous machine construction of a synchronous machine, i. Explain the constructional details of alternator in. Example 12 a 12 pole, 3phase, starconnected alternator has 72 slots. 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. In case of salient pole machines regulation is found out by applying blondels two reaction theory. Jun 04, 2015 voltage regulation it is clear that with change in load, there is a change in terminal voltage of an alternator. On the theory of salient pole alternators with electromagnet. Electrical machines iii electrical and electronics engineering time. What is the difference between a salient pole and a. The magnitude of this change depends not only on the load but also on the load power factor.
No load and blocked rotor test on 3phase induction motor. Be semestervith electrical question bank electrical. It has 6 slots per pole per phase, conductors per slot being 4. What are the advantages of a round rotor generator than a. Nonsalient pole the salient pole is most commonly used configuration. Manipal institute of technology manipal university. 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 motor field rheostat should be kept in minimum resistance position. In this method both the reactance drops are replaced by their equivalent mmfs. There are mainly two types of synchronous generator from rotor construction point of view. Ee6504 electrical machines 2 question bank regulation 20. The salient pole type of rotor is generally used for slow speed machines having large diameters and relatively small axial lengths. Now if the speed of the alternator is reduced to 750 rpm but the field current remains unchanged, the load current will become.