The value of the regulation not only depends on the load current but also on the power factor of the load. The voltage regulation of an alternator can be determined by different methods. Methods to determine voltage regulation of alternator q1. Regulation of alternator voltage electrical impedance scribd. To predetermine the efficiency and regulation of transformers and assess their performance. Eee lab manual pdf file electrical and electronics engineering pdf. Alternator on load synchronous reactance vector diagrams of loaded alternator voltage regulation rotherts m. To analyze performance of three phase induction motor. The range of abnormal conditions and faults that can occur is extensive, and many could result in serious damage to the alternator and associated plant.
Voltage regulation of alternator emf and mmf methods. This document does not claim any originality and cannot be used as a. Mmf method is used for determining the voltage regulation of an alternator or synchronous generator is also called ampere turns method or rotherts mmf method. Regulation of alternator free download as word doc. Before calculating the voltage regulation we need to calculate the following data. This document was uploaded by user and they confirmed that they have the permission to share it. Regulation of alternators is defined as the change in the terminal voltage from no load to full load at a given power factor the field current kept constant,expressed in terms of rated terminal voltage. Voltage regulation of an alternator by various methods. The synchronous impedance method or emf method is based on the concept of replacing the effect of armature reaction by an imaginary reactance. Actual load need not be connected to the alternator and hence method can be used for very high capacity alternators. The regulation of an alternator can be determined by various methods. The open circuit characteristic is the graph of the circuit.
Synchronous impedance method armature turn or mmf method zero pf or potier method synchronous impedance method gives result which is higher than the original value. V v e where v is the terminal voltage and e 0 is the induced voltage. In case of small capacity alternators it can be determined by direct loading test while for large capacity alternators it can be determined by synchronous impedance method. Mmf method of voltage regulation its phasor diagram. Electrical and electronics engineering lab manual pdf eee lab manual pdf.
Succinctly divided in 14 chapters, the book delves into important concepts of the subject which include armature reaction and commutation. To calculate voltage regulation of synchronous machine by m. Generally, we use this synchronous impedance method for highspeed alternators or synchronous generator. General physical consideration, torque and power relations in nonsalient pole and salient pole. Eee lab manual pdf electrical electronics engineering2020. The regulation of a synchronous generator alternator 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. To understand the significance of regulation of an alternators using synchronous impedance method. The synchronous impedance zs, found is always more than its value under normal voltage conditions and saturation.
Comment comment on the results of voltage regulation as determined from the above methods. The following are the three methods which are used to predetermine the voltage regulation of smooth cylindrical type alternators synchronous impedance emf method. The main advantages of this method is the value of synchronous impedance z s for any load condition can be calculated. Electrical machinesiii important questions pdf file emiii imp qusts please find the attached pdf file of electrical machines iii important questions. The method requires following data to calculate the regulation. For calculating the regulation, the synchronous method requires the following. Voltage regulation of synchronous generator using emf method. Electrical machines ii emf induced in the armature. Constructional features of round rotor and salient pole machines armature winding integral slot and fractional slot windings. Which method for finding percentage regulation is called pessimistic method. A no load voltage is induced in the stator coils of alternator when rotor is rotated by a prime mover.
Voltage regulation of alternator using synchronous impedance. Voltage regulation of an alternator is defined as the change in terminal voltage from no load to full load expressed as a percentage of rated voltage when the load at a given power factor is removed with out change in speed and excitation. Synchronous machines notes part2 electric equipment. Voltage regulation of an alternator electrical idea. What are the methods for determining regulation of an alternator. Voltage regulation of alternator and solved example youtube. Now lets calculate voltage regulation of synchronous machine by e. Synchronization of two three phase alternators, by a synchroscope method b three dark lamp method c two bright one dark lamp method 6. The regulation of a synchronous generator alternator is. Protection of synchronous generators involves the consideration of faults and harmful abnormal operating conditions, more so than the protection of other power system elements. Hence regulation of the alternator at any load condition and load power factor can be determined. Regulation of an alternator using the potier method aug 30 2011 12.
This mmf method is based on the results of open circuit test and short circuit test on an alternator. Regulation of 3phase alternator by zpf and asa methods 9. Methods to determine voltage regulation of alternator. Figure 1224 shows the circuit used to determine the synchronous impedance of a wyeconnected ac generator. Which of the following method can be used to determined the voltage regulation of an alternoator. Suppression of harmonics armature reaction leakage. Synchronous reactance from the above discussion, it is clear that for the same field excitation, terminal voltage is decreased from its noload value e0 to v for a lagging power factor. Mmf method of voltage regulation mmf method is also known as ampere turn method. Synchronous impedance method the synchronous impedance method or emf method is based on the concept of replacing the effect of armature reaction by an imaginary reactance. Regulation of three phase alternator by emf and mmf methods. Synchronizing method, effect of wrong synchronizing, load sharing between alternators in parallel.
The synchronous impedance method is based on the concept of replacing the effect of armature reaction by an imaginary reactance the magnetomotive force mmf. To determine voltage regulation of threephase alternator by synchronous impedance method. Regulation of alternators new regulation of alternators. Methods of finding voltage regulation in synchronous generator. Voltage regulation of synchronous machine alternator by. The open circuit characteristic is the graph of the circuit voltage and the field current.
To find the regulation of a three phase alternator by emf method. General physical consideration, torque and power relations in. Or the numerical value of the regulation is defined as the percentage rise in voltage when full load at the specified powerfactor is switched off with speed. Which of the method more accurate for determine the. Few requirements are there to calculate voltage regulation of synchronous machine by e. Regulation of an alternator using the potier method. What are all the various methods to determine the voltage regulation. The voltage regulation depends upon the power factor of the load. Synchronous impedance of a wyeconnected alternator the voltage regulation of a threephase alternator can also be determined using the synchronous impedance method. Pdf principles of electrical machines book by vk mehta. What is the difference between salient pole alternator and cylindrical rotor type alternator. Voltage regulation of an alternator by emf and mmf method. In their case, standard construction consists of armature winding mounted on a stationary element called stator and field windings on a rotating element called rotor. Normally for voltage regulation calculation, we use methods like.
The synchronous impedance method of finding the voltage regulation by a cylindrical rotor alternator is generally considered as the test data obtained at the rated speed on a threephase yconnected synchronous generator are given as follows. Electrical machinesiii important questions pdf file em. To start induction motor by rotor resistance starter 8. Phasor diagram of a cylindrical rotor alternator online test electrical machines questions and answers synchronous generators phasor diagram of a cylindrical rotor alternator online test voltage regulation of an alternator. For calculating the regulation, the synchronous method requires the following data.
Sudden short circuit of a synchronous generator, transient and subtransient reactances. Voltage regulation of alternator by mmfampere turn method. Adams engineering college, paloncha eee department emii lab experiment no. Distributed and concentrated windings distribution, pitch and winding factors e. To pre determine the regulation of an alternator at full load at different. The synchronous impedance method is based on the concept of replacing. Name the various methods for predetermining the voltage regulation of 3phase alternator. Voltage regulation of alternator using synchronous. Voltage regulation of an alternator instrumentation tools. In this method, the armature reaction is treated as another armature leakage reactance. To determine the regulation of a 3phase alternator by. A convenient way to compare the voltage behaviour of two generators is by their voltage regulation vr.
There are various methods for determination of regulation one of them is synchronous impedance method is based on the concept of. Hence, the value or regulation so obtained is always more, than that found from an actual test. Voltmeter ammeter ammeter rheostat tachometer connecting wires name plate details. Chapt r synchronous machines a s we have seen in section 4. Electrical and electronics engineering lab manual pdf. In case of small generators it can be determined by direct loading whereas in case of large generators it cannot determined by direct loading but will be usually predetermined by different methods. Synchronous alternator protection principles and systems. Short questions and answers ee1251 electrical machines ii. Three phase alternator by synchronous impedance and mmf method aim. Contents defination methods to determine voltage regulation 1 synchronous impedance method 2 mmf method 3 zero power factor method 3. There are 3 methods for determining voltage regulation of an alternator i. Voltage regulation of alternator and solved example ee academy. In the open circuit test for determining the synchronous impedance, the alternator is.
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