Why synchronous motor is not self starting

1. True. A magnetic field of constant magnitude but rotating at constant speed (synchronous speed) is produced in the stator. The speed of operation is always in synchronous with the supply frequency irrespective of load conditions Above a certain size, synchronous motors are not self-starting motors. This means that if one has got control over frequency of the electricity, speed of synchronous motor can be very accurately controlled. The synchronous motor and induction motor are the most widely used types of AC motor. This is because the speed with which rotating magnetic field is rotating is so high that it is unable to rotate the rotor from its initial position, due to the inertia of the rotor. The above method of starting synchronous motor as a squirrel cage induction motor does not provide high starting torque. The three-phase synchronous motor is a unique and specialized motor. 6 May 2015 In a single phase AC motor (at starting) there is only one pulsating field. An electrical motor is such an electromechanical device which converts electrical energy into a mechanical energy. The starter motor can be either a three-phase induction motor or a DC motor. If the synchronous motor is loaded to the point where the rotor is pulled out of step with the rotating magnetic field, no torque is developed, and the motor will stop. The load may now be placed on the synchronous motor. In case of three phase AC operation, most widely used motor is Three phase induction motor as this type of motor does not require any starting device or we can say they are self starting induction motor. 4 May 2019 Three phase synchronous motor is not self-starting because synchronous motor rotation is based on locking mechanism. Basically, there are two methods for starting synchronous   1φ Motors – Classification · Why 1φ IM not self-starting? Split Phase Induction Motor  Synchronous Motors Self-starting brushless synchronous motors for direct on line or inverter use. Several m . Generally the construction of the synchronous motor is electrically more efficient than a non-synchronous Normally synchronous motors are not inherently self-starting motor. (a) Explain why a single phase squirrel cage induction motor is not inherently self starting. Why the synchronous motor is not self-starting. This differs from an induction motor squirrel cage in that it is not rated to carry load, but only to assist in starting. Procedure to start a Synchronous Motor: Now suppose the rotor is rotated by some external means at a speed almost equal to synchronous speed . As the power factor of the system is improved by the action of synchronous condenser, the drop of volts from the sending to receiving end on the line is decreased and the regulation of the line is improved. f so seperate source is not necessary. The various methods to start the synchronous motor are, 1. Let us see the  Single-phase 60 Hz 1800 RPM synchronous motor for Teletype Therefore, it is self-starting and doesn't need an  If the de field excitation is changed, the power factor of a synchronous motor can for starting because the synchronous motor isn't self-starting without this feature. The speed of the synchronous motor is independent of the load, i. They can operate  18 Apr 2018 Synchronous motors are not self-starting. Motor starting with an external prime Mover: Synchronous motors are mechanically coupled with another motor. But in Synchronous motor, the flux produced in the rotor for the applied external DC supply. Single phase motor Working principle of single phase induction motor. When DC supply is given to stationary rotor unlike poles will try to attract each other. They are self-starting and do not need additional winding. c. To make it self-starting, it can be temporarily converted into a two-phase motor while starting. e two electrical inputs are provided to it. This has a wide hysteresis loop which means once it is magnetized in a given direction; it requires a large reverse magnetic field to reverse the magnetization. The damper winding consists of short circuited copper bars embedded in the the face of the rotor poles Best Answer: "The synchronous motor is made self starting by providing a special winding on the rotor poles, known as damper winding or squirrel cage winding. This means that the Synchronous Motor is not Self Starting. m. Assume any instant like that two poles are in line with stator magnetic axis [A-B]. First step is to de-energize the field winding by shorting it through a suitable resistor and then connect stator of synchronous motor to three phase supply. Practically it is not possible for stator poles to pull the rotor poles from their stationary position into magnetic locking condition. Reluctance Synchronous Motors Single-Phase motors are not self-starting but Split-phase motors are the solution. It is not synchronous. (b) Describe the construction and principle of operation of split phase motor. Starting Methods of Synchronous Motor. Stalling If a motor becomes stalled, it will not overheat and will continue to draw only rated current. Explanation: Why is an induction motor self-starting? 3 phase induction motor is self-starting because it consists of cage windings of parallel conductors (made up of copper or aluminum) short-circuited at the ends by end rings, hence forming a closed path for current flow. As seen earlier, synchronous motor is not self starting. Damper winding is provided on the rotor of the synchronous motor. One is 3 phase supply given to stator and other is DC excitation given to rotor of the  Synchronous motor is starting in a more current so it is not self started. The starter of a synchronous motor is fed my three phase AC current while the rotor is fed by DC current. When rotor is initially at position (a) The like pole of rotor will get repelled and the tendency of rotor will be to rotate in anticlockwise Why 3-Phase Induction Motors are Self-Starting but 3-Phase Synchronous Motors Not? Let us consider a 3-phase induction motor first and see how it rotates. Rotor of an induction motor rotates slower compared to the magnetic fields produced by stators. The difference between the two types is that the synchronous motor rotates at a rate locked to the line frequency since it does not rely on current induction to produce the rotor's magnetic field. The synchronous motor is not self-starting. This is the reason why they are suitable for high precision applications. Synchronous motors are generally of the salient pole type. This is possible by various method in practice. Synchronous motor starting methods. why synchronous motor is not self starting. So the synchronous motor is not self-starting. . 7 – Hysteresis Synchronous Motor. e. In the previous article we came to know that synchronous motors are not self starting so to make them start automatically we should add some tweaks. Using damper winding 3. Why Synchronous motors are not self starting ? But if the rotor has got no initial rotation, situation is quite different. Why Three Phase Synchronous Motor not Self Starting? When a three-phase supply is given to the stator of a three-phase wound synchronous motor, a rotating field is set up in the air gap which rotates at a synchronous speed (Ns = 120f/p). The motor starts up. So to achieve this, instead of shorting the damper winding, it is designed to a form a three phase star or delta connected winding. Summary: Single-phase induction motors • Single-phase induction motors are not self-starting without an auxiliary stator winding driven by an out of phase current of near 90°. When three phase supply is given to the stator the stator poles rotates at synchronous speed but rotor could not able to catch the synchronous speed (or ) stator speed then quick reversal as that of the stator poles due to mechanical inertia of the rotor then the stator is subjected to clock wise torque and rotor is This is because the speed with which rotating magnetic field is rotating is so high that it is unable to rotate the rotor from its initial position, due to the inertia of the rotor. The moment of inertia of rotor stops the large-sized synchronous motors from self-starting. Main Features of Synchronous Motor. Why the synchronous motor is not self started. When the motor isbrought to synchronous speed, AC current is applied to the stator windings. Why Single Phase Induction Motor is not Self Starting? According to double field revolving theory, any alternating quantity can be resolved into two components, each component have magnitude equal to the half of the maximum magnitude of the alternating quantity and both these component rotates in opposite direction to each other. why? The answer is pretty simple, synchronous motor drives makes the starting, pull in and braking process smooth and without any problems. It is not synchronously revolving (or rotating) flux, as in case of 3 phase stator winding, the fed cannot produce rotation. First, main field winding is short-circuited. Why Synchronous motor is not self starting? Now, the stator poles are revolving with synchronous speed (lets say clockwise). In synchronous motors that contain a squirrel cage winding for self-starting, the squirrel cage will also provide damping. 1(a). speed,then it continues to rotate at sync. One is 3 phase supply given to stator and other is DC excitation given to rotor of the motor. Starting Synchronous Motors. So under any case, whatever may be the starting position of the rotor, synchronous motor is not self starting. (a) Explain the importance of distributed armature winding in a synchronous generator. Therefore, a synchronous motor can be made to carry the mechanical load at constant speed and at the same time improve the power factor of the system. Hence the need to build into the rotor additional windings if standstill starting is required in the particular synchronous motor application. And the motor runs at the synchronous speed. Just to get the feel of it imagine field of stator rotating at 1500 r. It could be either 3 phase induction motor or DC shunt motor. Using small d. A synchronous motor is not self starting. Learn about the speed/torque characteristics and centrifugal switches used for starting. 3) Why is not synchronous motor self-starting? 4) Which winding is vital for synchronous motor starting? 5) What will happen if you connect a 60-Hz device to a 50-Hz system? 6) How does a synchronous machine differ from an induction machine? 7) What is the basic difference between a synchronous generator and a DC generator? 2 characteristics that make the synchronous motor different from an induction motor. But in practice it is not possible to give initial torque to rotor externally hence some modifications are done in the construction of single phase induction motors to make them self starting. In this, when a synchronous motor is connected directly to a three phase AC supply without any starter, a very large stator current flows through the stator winding. After inserting squirrel cage arrangement into synchronous motor it start like induction motor. mainly alternator,synchronous motor comes under the synchronous machine. When rotor is rotate on synchronous speed the relative speed of rotating Difference Between Induction Motor and Synchronous Motor Rotor Speed. Three phase synchronous motor is not self-starting because synchronous motor rotation is based on locking mechanism. The first step is to accelerate the motor to near synchronous speed. In a three phase induction motor, the rotating magnetic field is created by the fluxes of the three phase windings which are displaced by 120 degrees. Basically there are three Method to Starting the  (As Ns = 120f / P); Synchronous motors are not self starting. the motor is not inherently self starting b. The DC excitation of the synchronous motor is turned off initially. While starting a modern synchronous motor provided with damper windings, following procedure is adopted. Synchronous motor is not self starting but the damper winding makes it self starting. Induction motor works in the principle of electromagnetic induction but synchronous motor works in the principle of attraction or locking. Q: Why synchronous motor is not self starting? Synchronous motor is a doubly excited machine i. Answer / santosh kumar sharma. Synchronous motor is Not self starting , Inducion motor is self starting 2. 8 Jun 2016 of synchronous motor is used with a magnet rotor to improve the The measurement of the rotor position is not necessary for starting and  22 Mar 2017 Synchronous motors are inherently not self starting. Basically there are three methods that are used to start a synchronous motor: The synchronous motor winding isn't wound the same way and it can't produce a rotating field [or starting torque] in the same manner as the wound rotor induction motor. and rotor is stationary, it can't simply get locked to stator field due to its inertia. 16 Mar 2016 Why synchronous Motor Is Not Self Starting. Synchronous Motors, Excitation & Control We Drive Industry Slide 17 Western Mining Electrical Association - May 2009 Synchronous Motor Model - Starting POWER SOURCE •s One Phase Model •AC Power on stator sets up rotating field magnetic flux •For starting, rotor amortiseur acts as shorted transformer The synchronous motor when used for the above purpose is called synchronous phase modifier. Rotors of a synchronous motor rotate at the same speed at which the magnetic field formed by the stator is rotating. Before that we need to know why single phase induction motor is not a self starting motor and how the problem is overcome. When the power supply is switched on, the armature winding and field windings are excited. At synchronous speedthe rotor poles lock to the rotating magnetic field, beacause of the constant magnetic field in the rotor these cannot use induction windings for starting . Some additional devices should be used to start the motor. This property is due to the inertia of the rotor. It is not necessary to consider high starting currents when designing a control system for a Superior Synchronous motor, since starting and operating current are, for all practical purposes, identical. By controlling the frequency, speed can be varied. The stator carries windings connected to an AC supply to produce a rotating magnetic field. So how does the motor still run at synchronous speed? motor resembles, three-phase, squirrel-cage motor except that, single phase induction motor has no starting torque and some special arrangement have to be made to make it as self starting. Since the rotating magnetic field can be represented by two stator pole revolving at synchronous  The average electromagnetic torque is zero, which can not make the rotor accelerating. At this instant, rotor poles are arbitrarily positioned as shown in the below figure. Another theory which can also be used to explain why single phase induction motors is not self starting is cross-field theory. At some instance the north pole of starter magnetic field will coincide with the north of rotor magnetic field and the very next second the poles will be opposite, that is N S, so this will make the rotor to stand still until an external force is applied to start the rotation. Robert Spiewak, P. The synchronous machine, however, is not self-starting. Basically there are three methods that are used to start a synchronous motor: to it and bring the synchronous machine to near about its rated speed (but not. Starting of a Synchronous Motor A synchronous motor is a device which converts the AC into mechanical work at synchronous speed. Reduced voltage with the help of auto-transformers is applied across stator terminals. p. Why the synchronous motor is not self-starting? 19 May 2017 a) not self starting b) self a) it can not be started under load A synchronous machine with its field winding on stator and polyphase armature  2 Jun 2019 A synchronous motor is not inherently self starting. This motor is not self starting it requires some additional devices to start the motor. We have some fine methods to start the synchronous motor. Procedure for Starting a Synchronous Motor. Starting Large AC Motors For IEEE Houston Section –CEDSeminar By: Roy Cosse, P. Derive an expression for distribution factor for such a winding. A 3-phase synchronous motor as shown in the figure below generates an electrically rotating field in the stator. To overcome this problem and to make the motor self-starting, it is temporarily converted into two-phase motor during starting. Synchronous motors are not self-starting. synchronous motor is not self-startingmain reason behind that ia. Three-phase synchronous  15 May 2018 Synchronous motors have lots of advantages but being not self-starting unlike 3 phase induction motors, is a major disadvantage. Crawling and cogging Crawling and cogging in squirrel cage induction motor. On literature [3], a variety of  2 Nov 2018 The synchronous motor is an AC motor that works at a fixed speed in a Synchronous motors are not self-starting motors because the torque  inherent self-starting characteristic has prevented the synchronous machine Although the induction motor speed need not vary very much, there is still need  This is about Construction of Synchronous Motor and how it works. N vs S), approaches and attracts the rotor backwards, until it passes by and then pulls the rotor forward. if a synchronous motor moves with more than synchronous speed then it acts Methods of Starting of Synchronous Motor. Why synchronous motor is not self starting? A synchronous motor working on leading power factor and not driving any mechanical, which is known? What are the methods of starting synchronous motor? What is the effect on speed if the load is increased on a 3 phase synchronous motor? Hello. The starting of the Synchronous Motor does not take place on its own. Starting Synchronous Motors The problem with synchronous motors are that they are not self- starting. Best Answer: induction motors have low starting torque. Let us have a detailed information on this topic. Most synchronous motors are equipped with a squirrel cage winding on the rotor for starting purposes. Unlike three phase induction motors, single phase types are self starting. Answer / tapiwanashe because the torque is only developed when the synchronous motor is running at the speed of magnetic flux , therefore, the motor needs some type of device such as damper winding to bring the rotor to synchronous speed ANS) Speed of the rotor in Induction motor depends on how fast the stator magnetic field rotates, which means it depends on the frequency of the 3-phase currents fed to the stator. For the sake of analysis only it could be represented by two rotating . Q5) Why 3 phase synchronous motor is not self-starting? ANS) In synchronous motor we have two excitation. In synchronous motors, the stator has 3 phase windings and is excited by 3 phase supply whereas the rotor is excited by DC supply. We know that the ac supply is a sinusoidal wave and it produces pulsating magnetic field in uniformly distributed stator winding. High speed accuracy and a wide regulation range. So under any case, whatever may be the starting position of the rotor, the synchronous motor is not self-starting. Three Phase Induction Motor does not need any starter for starting, or in other words three phase induction motor is self-starting. The actual difference between Synchronous Motor and Induction Motor is, In Induction motor, the flux produced in the rotor for Mutual Induction between stator and rotor coil. The DC motor nowacts as a DC generator and supplies DC field excitation to the rotor of the synchronous motor. Synchronous Motor Interview Questions. The synchronous machine has to be rotated to near the synchronous speed of the stator before it can “catch” the stator field and begin rotating on its own. Such motors are not self-starting if started from a fixed frequency power source such as 50 or 60 Hz as found in an industrial setting. These machines are made self starting by providing a special winding in the rotor poles, known as damper winding or squirrel cage windings. Hence, stator of a single phase motor has two windings: (i) Main winding Q: Why synchronous motor is not self starting? Synchronous motor is a doubly excited machine i. AC supply given to the stator produces a rotating magnetic field which causes the rotor to rotate, therefore, in the beginning synchronous motor provided with damper winding starts as a Fig. The starter motor helps the synchronous motor accelerate and rotate at speed close to its synchronous speed, at which the DC excitation is turned on. If the rotor position is such that, N pole of the rotor is near the N pole of the stator (as shown in first schematic of above figure), then the poles of the stator and rotor will repel each other, and the torque produced Synchronous motors have lots of advantages but being not self-starting unlike 3 phase induction motors, is a major disadvantage. State the characteristic features of synchronous motor. To overcome this problem and to  15 Dec 2016 Synchronous motor is not self starting motor,hence external DC source is necessary. Because of this inertia of the rotor, it is not possible for a rotor to get in sync with the stator’s magnetic-field at the very instance power is applied. DWQA Questions › Category: Induction Motor & Generator › Why are 3-phase induction motors self-starting, but 3-phase synchronous motors are not? 0 Vote Up Vote Down Lal Singh asked 1 year ago 2 Answers 0 Vote Up Vote Down admin Staff answered 1 year ago 3 Phase Induction Motor- Expression for Torque- T= (V^2)* (R2)/(w […] Why synchronous Motor Is Not Self Starting Consider the rotating magnetic field as equivalent to physical rotation of two stator poles N 1 and S 1 . That is an initial torque is required for the motor to get started. It’s stator winding which consists of a 3 phase winding is provided with 3 phase supply and rotor is provided with DC supply. That is why a single phase motor is not self-starting. E. Synchronous motors are generally not self-starting because (a) the direction of rotation is not fixed (b) the direction of instantaneous torque reverses after half cycle (c) startes cannot be used on these machines (d) starting winding is not provided on the machines 3-Phase Synchronous Motors. Hence single phase induction motor is not self-starting. Because of  Synchronous motors are not self-starting. However, if the motor is stalled by Click here 👆 to get an answer to your question ️ synchrounous motor is three phase motor,but its not self starting . The starting torque can be given to the motor by applying a mechanical rotation to the motor shaft. We shall discuss about them one by one. This property is due to the inertia of the rotor; it cannot  Thanks A2A The synchronous motors are doubly excited. We… To get a clear idea about this question consider a rotating magnetic field as equivalent to physical rotation of two stator poles N1 and S1 as shown in the figure. We should rotate rotor near to the speed of synchronous speed,so it attains synchronous speed. Available squirrel cage induction motor starting methods include direct-on-line starting, reduced-voltage reactor or auto-transformer starting, star-delta starting or, increasingly, new solid-state soft assemblies and, of course, variable frequency drives (VFDs). Best Answer: The rotor will start to move toward a rotating pole that is passing by, but before it gets very far (in an angular sense), the adjacent rotation pole, which is the opposite polarity of the one that just passed (i. To make synchronous motor self start the squirrel cage arrangement insert into rotor part of the motor. Why We Need Soft Starting for Synchronous Motors? Let us take a case where the synchronous motor is started initially as an induction motor and brought to synchronous condition later. In this chapter, we shall focus our attention on the construction, working and characteristics of commonly used single-phase motors. Thanks A2A The synchronous motors are doubly excited. Other Comparisons Between Synchronous Motor and Induction Motor are explained here Self-starting polyphase induction motors produce torque even at standstill. As a slip ring induction motor 4. Introduction In my last article, we have seen about the single phase induction motor’s construction and reasons for not being a self-starting motor. Using pony motors 2. Answer 3. 2. Consider an instant when two poles are at such a position where stator magnetic axis is vertical, along A-B as shown in the Fig. Moreover, the 3-phase PM Synchronous motor is very suitable for use where a precise constant speed is required by varying the frequency of the source to a nominal value which then allows the motor to operate at its rated speed [1, 283-330]. Why single phase IM is not self-starting? AC synchronous generator (alternator) Construction and working of alternator. Synchronization of an Applications Of Synchronous Motor Damper winding Method Electrical Machines How Rotor Rotates at Synchronous Speed? Methods of Starting of Synchronous Motor Pony motor Pony motor method Starting of Synchronous Motor Synchronous Motor Synchronous Motor Working Principle why synchronous motors are not self starting Why is the single phase motor not self starting For an induction motor to be self starting, the stator needs to have a rotating magnetic field. Just to get the feel of it  To get a clear idea about this question consider a rotating magnetic field as equivalent to physical rotation of two stator poles N1 and S1 as shown in the figure. a synchronous motor is not a self starting motor. a. At any speed other than synchronous speed, its rotor would experience an oscillating torque of zero average value as the rotating magnetic field repeatedly passes the slower moving rotor. We use either induction motor principle A single phase induction motor is not a self-starting motor, so it requires some starting means for working. Synchronous Motor Starting Methods Electrical Machines In the previous article we came to know that synchronous motors are not self starting so to make them start automatically we should add some tweaks. Is it possible to start the DG set by switching on the main breaker of alternator to allow utility power in to the alternator keeping excitation manually very low, to behave like synchronous AC motor. To be able to explain why a synchronous machine is not self starting To be able to describe how to start a three phase synchronous machine with a prime mover To be able to describe how to synchronise a three phase synchronous machine to the mains supply To be able to describe how to start a synchronous machine with a pony motor 1. Find Study Resources. Here we have explained Why Three Phase Induction Motor Self-Starting but Synchronous Motor not Self-Starting. Also know Working principle Hence synchronous motors are not self starting. However, if the rotor of such a machine is given an initial start by hand (or small motor) or otherwise in either direction, then immediately a torque arises and the motor accelerates to its final speed (unless the applied torque is too high). In Synchronous motor Seperate DC source is required for rotor excitation, while in Induction motor Rotor gets excited by the induced e. synchronous motors are not self-starting motors. This can be achieved by introducing an additional 'starting winding' also called as auxillary winding. The 3 phase AC to stator produces Rotating Magnetic Field (RMF) in the air gap, this rotates at Syn At starting position of synchronous machine, the rotor could have any alternative position as shown here. As explained above, single phase induction motor is not self-starting. Construction and working of double squirrel cage motor. 8M 7 a Why synchronous motor is not a self starting Explain the starting from CSE 509 at Sri Sivani College of Engineering. Here, we do not apply DC excitation initially. A 3- phase supply given to the armature of Induction Motor produces a rotating magnetic field. of the alternating poles, the net torque is zero and the motor does not start. while running it maintains a constant speed equal to Q. It rotates at speed very close to its synchronous speed, and then we give the DC A synchronous motor may be started by a DC motor on a common shaft. They need some external force to bring them near to the synchronous speed. • The auxiliary winding of a permanent split capacitor motor has a capacitor in series with it during starting and Synchronous motors are not self starting machines. A synchronous motor with only a field winding carrying a direct current would not be self-starting. Self-starting with low torque . The answer is pretty simple, synchronous motor drives makes the starting, pull in and braking process smooth and without any problems. SYNCHRONOUS MOTORS – Electrical Engineering Interview Questions and Answers :-1. Once started the auxiliary winding is optional. I know that the reason the rotor runs at synchronous speed is because the poles created by the excitation current are attracted to those of the stator. It can be started by the following methods given below. A synchronous motor is not self-starting and an auxiliary means has to be used for starting it. Methods of Starting a Synchronous Motor. However when it is provided with some prime mover ,which rotates it up to 80% of sync. Starting of synchronous motor by damper winding and pony motor, by using a small dc machine. The DC field in the rotor will only synchronize with the rotating field in the stator if the  28 Jul 2017 Synchronous motor is widely used in industries. In a non self starting clock there is a manually operated device which runs the motor up to  10 May 2018 along one space axis only. If we lost battery power or self starting motor of a 300KVA diesel generator but we have utility power. Synchronous motors are not self-starting and therefore require a method of bringing  However, it must be noted that synchronous motors are not self-starting. this is the reason why synchronous motors are not self starting. machine Best Answer: The rotor will start to move toward a rotating pole that is passing by, but before it gets very far (in an angular sense), the adjacent rotation pole, which is the opposite polarity of the one that just passed (i. When a synchronous motor is overloaded, the rotor is forced out of synchronism with respect to the rotating stator field and the motor slows down. It is necessary to rotate the rotor at a speed very near to synchronous speed. But this all depends on existence of magnetic locking between stator and rotor poles. Self Starting. , the variation of the load does not affect the speed of the motor. The speed of the motor can only be changed by changing the frequency of the supply. Everyone is saying synchronous motors are not self starting but why here we going to discuss if you don't have time to read this whole article to know why synchronous motor is not self starting ANSWER IS INERTIA OF ROTOR. Starting synchronous motors is a two-step process. A synchronous motor is not a self-starting motor because torque is only developed when running at synchronous speed; therefore, the motor needs some type of device to bring the A three phase synchronous motor can produce a leading power factor. They require some external means to bring their speed close to synchronous speed to  It can run either at synchronous speed or not at all i. False. Presentation Code: 214 March 22-23, 2016 Review induction and synchronous motor operation and effect Why synchronous motor is not self starting? A synchronous motor is not a self starting motor because torque is only developed when running at synchronous speed, therefore ,the motor needs some type of device to bring the rotor to synchronous speed Methods of starting synchronous motor By reducing supply frequency. If we reduce the current to 0 though, there are no poles on the rotor to be attracted. The problem with synchronous motors are that they are not self- starting. speed even after prime Why synchronous motors are not self starting? The stator of synchronous motor is fed by a three phase supply. 3. why synchronous motor is not self starting

ds, ys, kl, hm, ju, jj, xw, qa, tn, l7, n8, 3i, m4, ae, qf, nx, fr, 0u, au, 7r, 8h, is, 1u, s5, uv, pw, wb, wc, kn, hj, iq,

: