Equivalent circuit of a single phase induction motor the equivalent circuit of a single phase induction motor can be obtained by two methods named as the double revolving field theory and cross field theory. Single phase motors learning objectives types of single phase motors single phase induction motor double field revoling theory making single phase induction motor selfstarting equivalent circuit of single phase induction motor without core loss equivalent cuicuit with core loss types of capacitors start motors capacitor startandrun. This theory for single phase states that a stationary pulsating magnetic field can be resolved into two rmf, each of equal magnitude but rotating in the opposite direction. Each of these components rotates in the opposite direction i. The stator winding is excited by the single phase a. The singlephase induction motor is much the same in construction as the threephase motor. Equivalent circuit of single phase induction motor. In order to obtain a revolving air gap field and electromagnetic. The resultant of the two fields of equal magnitude rotating in opposite directions is alternating. Two theories have been suggested to find the performance of a single phase induction motor. Well, a single phase induction motor with its main winding alone can be represented as shown in figure below. Refer back to this diagram as the operational requirements of the singlephase motor are discussed.
In motors that operate with both windings energized,the winding with more wire more turns is known as main winding and the other is called auxiliary winding. The single phase induction motor circuit is given by double revolving field theory which states that a stationary pulsating magnetic field might be resolved into two rotating fields, both having equal magnitude but opposite in direction. In this single phase induction motor slip rings and commutators are not used, so their construction becomes very simple and easy. Apr 21, 2017 consider a single phase induction motor with standstill rotor. The doublefield revolving theory states that, any alternating quantity here, alternating flux can be resolved into two components having magnitude half of the. Double field revolving theory of single phase induction motor. Single phase induction motor double revolving field theory a singlephase ac current supplies the main winding that produces a pulsating magnetic field. The 3phase set of currents, each of equal magnitude and with a phase. Analysis of a singlephase capacitor induction motor operating at two power line frequencies. Working principle of a single phase induction motor. According to the double field revolving theory, this alternating flux. And gives more torqueamp than any other single phase motor. May 22, 2016 double revolving field theory of single phase induction motor double revolving field theory.
Double revolving field theroy electrical engineering. A given data of single phase induction motor is taken from laboratory and its equivalent circuit is obtained through the double revolving theory. Double field revolving theory when fed from a single phase supply, its stator winding produces a flux or field which is only alternating i. This strange behavior of single phase induction motor can be explained on the basis of double field revolving theory. Jul 11, 2019 the construction of the stator of the single phase induction motor is similar to that of three phase induction motor except there are two dissimilarities in the winding part of the single phase induction motor. The absence of slip ring and brushes make the construction of single phase induction motor very simple and robust. Cross field revolving theory is the theory which discuss the cause of single phase induction motor not to be self starting. Double revolving field theory of single phase induction. Aug, 20 single phase induction motor, how it works. Single phase induction motor, theory of operation double revolving field theory, equivalent circuit, determination of parameters methods of starting, split phase. Firstly, the single phase induction motors are mostly provided with concentric coils. According to double field revolving theory, we can resolve any alternating quantity into. A singlephase ac current supplies the main winding that produces a pulsating magnetic field.
Working principle of a single phase induction motor circuit. According to double revolving discipline principle, bear in mind the 2 additives of the stator. The difference between the forward and the backward torque is the net torque acting on the rotor. Jun 05, 2011 the single phase induction motor resembles, three phase, squirrelcage motor except that, at full speed, only a single winding in the stator is excited. Rotating magnetic field in a single phase ac motor duration. Single phase induction motor electromagnetic induction.
Performance characteristics and double revolving theory of single phase induction motor yahaya asizehi enesi 42 theory that is applicable to variety of induction motor types. Firstly the equivalent circuit is developed on the basis of double revolving field theory when only its main winding is energized. Double revolving field theory a single phase ac current supplies the main winding that produces a pulsating magnetic field. When the stator winding distributed one as stated earlier carries a sinusoidal current. The basic idea of an electric motor is to generate two magnetic fields. Imagine the single phase induction motor is made up of one stator winding and two. Why single phase induction motor is not self starting.
The single phase induction motor has distributed stator winding and a squirrelcage rotor when fed from a single phase supply, its stator winding produces a flux or field which is only alternating i. Pdf analysis of a singlephase capacitor induction motor. The analysis of the single phase motor can be made on the basis of two theories. In a single phase motor we have only a single field winding excited with alternating current. According to double revolving field theory, consider the two components of the stator flux, each having.
Double revolving field theory a singlephase ac voltage supplies the main winding that produces a magnetic field change with time around one access so that this field call as pulsating. This theory makes use of the idea that an alternating uniaxial quantity can be represented by two oppositelyrotating vectors of half magnitude. Aug 24, 2018 there is a difference between single phase and three phase equivalent circuits. Double revolving theory is perhaps the easier of the two explanations to understand so we will discuss the double revolving theory only. Single phase induction motor, theory of operation double revolving field theory, equivalent circuit, determination of parameters methods of starting, split phase starting, repulsion starting, shaded pole starting, performance characteristics. A single phase induction motor exhibits a pulsatingintime air gap field and a pulsating torque. Consider two magnetic fields represented by quantities oa and ob of equal magnitude revolving in opposite directions as shown in fig. Single phase induction motor working principle and construction. Working principle of a single phase induction motor javatpoint.
Revolving field theory of single phase induction motors. Double field revolving theory the double field revolving theory of single phase induction motor is proposed to explain this problem of no torque developed at starting and yet torque once rotated. Equivalent circuit of a single phase induction motor. Single phase motor is nothing but a running a squirrel cage induction motor using a single phase power supply. Single phase induction motors questions and answers. Performance characteristics and double revolving theory of. The double revolving field theory is used to develop the equivalent circuit of single phase induction motor. Single phase im double field revolving theory youtube.
The double revolving field theory of a single phase induction motor states that a pulsating magnetic field is resolved into two rotating magnetic fields. In case of single phase induction motors, the stator winding produces an alternating magnetic field having maximum magnitude of. The double revolving field theory of a single phase induction motor states that a pulsating magnetic field is resolved into two rotating magnetic. Feb 28, 2017 operating principle the singlephase induction motor operation can be described by two methods. In this video concept of double revolving field theory, main winding, auxiliary winding, and the way motor is made self start is explained in. The induction motor responds to each of the magnetic fields separately. Double revolving field theory of single phase induction motor. Working principle of a single phase induction motor circuit globe. Performance characteristics and double revolving theory of single.
Before going into the details of revolving field theory, first we should know why do we need to study this theory. Aug 10, 2016 construction of single phase induction motor. Some singlephase induction motors are also called squirrel cage motors because of the rotors similarity. They are equal in magnitude but opposite in directions. Revolving field theory is used for the analysis of behavior of single phase induction motor.
Oct 08, 2016 revolving field theory is used for the analysis of behavior of single phase induction motor. Types of single phase induction motors and double revolving. The following section describes about the double revolving field theory and the prtnciple of operation of single phase induction motors. Starting methods for singlephase induction motor nptel. The doublefield revolving theory is proposed to explain. The double revolving field theory can be effectively used to obtain the equivalent circuit of a single phase induction motor.
Another important difference between the two is that the d. According to double revolving field theory, consider the two components of the stator flux, each having magnitude half of maximum magnitude of stator flux i. Mathematically, the pulsating field could be divided into two fields, which are rotating in opposite directions. This theory makes use of the idea that an alternating uniaxial quantity can be represented by two oppositely rotating vectors of half magnitude. Equivalent circuit for an induction motor electrical4u. Double revolving field theory and cross field theory are two ways of explaining the same phenomenon in single phase induction machines. Sep 06, 2019 it can be expanded through specific starting techniques to make the motor selfstart by itself. Explain why single phase induction motor does not start in the light of doublefield revolving theory. Single phase motor can be wound for any even number of poles i. The basic idea behind the double field revolving theory is that any alternating quantity can be resolved into 2 equal components rotating in opposite direction. How cross field theory expains about single phase induction. The magnetic field of the single phase motor does not rotate and it creates pulses in the same and opposite direction. Double revolving field theory of single phase induction motor double revolving field theory. Single phase induction motor free download as powerpoint presentation.
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