Difference between cylindrical and salient pole machines


Synchronous machine. (C) 3. Cylindrical rotor type ii. [22] [23] The construction of synchronous motor is similar to that of a synchronous alternator. Sometimes, they are also called as drum rotor. Cylindrical rotor seen in Recips, GTs and STs Salient pole rotor seen in Hydros More poles to obtain nominal frequency at low RPM Eq: f= [RPM/60] * [P/2] = [RPM * P] / 120 Cylindrical (Round) Salient Generator Protection Rotor Styles 7 Cylindrical Rotor & Stator Generator Protection 8 Construction of alternator the ac generator or synchronous generator is a machine which converts the mechanical power or energy into electrical power the construction of an alternator is very similar to the dc generator but the main difference between t The poles & pole shoes (which cover 2/3 of pole pitch) are laminated to minimize heating due to eddy currents. In order to prevent the peripheral speed from exceeding the safe limit, the diameter of the rotor is kept down. Owing to the high-speed, they have either two poles or four poles. Both of these types are synchronous machines. What is critical speed of Alternator? 7. As the • Salient-pole rotors – Used for low speed applications (<300rpm) which requil b f l hi idire large number of poles to achieve required frequencies (e. Research on permanent magnet synchronous motor rotor information control based on MRAS algorithm Jun 10, 2015 · Rotor • Rotor is the rotating part of the machine • Can be classified as: (a) Cylindrical Rotor and (b) Salient Pole rotor • Large salient-pole rotors are made of laminated poles retaining the winding under the pole head. In cylindrical rotor machine air gap is uniform and therefore, its reactance remains the same, irrespective of the spatial position of rotor. (B). 2 Pole Motors v s. The air gap in this space is larger and the reluctance offered to magnetic fluxes along this path is also larger. projected pole type construction. Salient-pole rotor: # of poles: large number Rotors are made laminated to reduce eddy current losses. Difference between salient pole & cylindrical pole rotors: We can define a synchronous generator or alternator as a machine which converts mechanical energy into alternating type electrical energy. They are smaller in diameter but having longer axial length . It has a large number of projecting (salient) poles, having their cores bolted or dovetailed onto a heavy magnetic wheel of cast-iron, or steel of good magnetic quality (Fig Salient pole type: Salient pole type rotor is used in low and medium speed alternators. What are the constructional differences between salient pole alternator and cylindrical rotor type alternator? 4. C generator? The function of carbon brush is to collect current from the commutator and supply is to the external load circuit and to the field circuit. Sep 24, 2015 · The stator is a stationary armature. 49) in Eq. Salient Pole Rotor. f = frequency, and. Model of a cylindrical synchronous generator. Sometimes, they are also called as drum rotor or cylindrical Rotor. find the line valve of the produce emf if coil are short piten by 3 slots. 4). What are the advantages of salient pole type of construction used for synchronous machines? ·They allow better ventilation. Apr 25, 2018 · To summarize, the main differences between the Cylindrical Rotor and Salient Pole machines are as follows: In salient pole type of rotor consist of large number of projected poles i. Damper windings are not needed in non-salient pole rotors Jun 25, 2011 · • High speed machines with cylindrical (or non salient pole) rotors • Low speed machines with salient pole rotors Figure 4. 1. A The rotor poles of a synchronous machine can be controlled in order to a system with a pair of identical coaxial cylindrical magnets, the force can be. In general, the Cylindrical Rotor type  4 Mar 2014 Rotors of an electrical machine are classified as: (i) Salient pole rotors and The construction of non-salient pole rotor (cylindrical rotor) is as  Difference between Salient pole and Non-Salient pole rotors or salient pole alternator and Cylindrical alternators used in Synchronous Generator. turbo alternators, which run at very high speeds. for which salient pole machines are designed is about 10 m/s while turbo. p. Causes excessive Difference Between Squirrel Cage and Slip Ring Motors. In some machines or when a large number of poles are needed, a salient pole rotor is used. vt. Example: A 450 volt, 50 Hz, ∆ connected, 4 pole, 3-phase synchronous generator has direct axis But in real salient pole synchronous generators air gap between stator and rotor is uneven 𝛿≠𝛿𝑚, thus flux density curves are as shown in fig. Non-salient pole rotors are cylindrical in shape having parallel slots on it to place rotor windings. Most hydraulic turbines have to turn at low speeds (between 50 and 300 r/min) 2. Blondel is credited for the theory. 180 electrical degree is accounted as the angle between adjacent North and South poles. 17 Various Types Salient-pole synchronous machine Cylindrical or round-rotor synchronous machine PowerPoint Presentation: Most hydraulic turbines have to turn at low speeds (between 50 and 300 r/min) A large number of poles are required on the rotor Hydrogenerator Turbine Hydro (water) D » 10 m Non-uniform air-gap N S S N d-axis q-axis Salient Jun 08, 2015 · 2. Mention the uses of damper winding in a synchronous machine. The three-phase synchronous machine, illustrated in Figure 1, is literally a DC machine turned inside-out. Armature Reaction When the rotor is spun, a voltage EA is induced in the stator Two types of rotors are used in alternators. 2 Salient pole type rotor 1. As the synchronous generator is loaded, the rotor position pulse advances with respect to the zero crossing of the power Large motors and generators (typically rated over 7 MW) are available in both 4-pole and 2-pole designs. 31 Oct 2016 In general, the Cylindrical Rotor type machines are confined to 2 and 4 pole turbine generators, while salient pole types are built with 4 poles  1 May 2018 salient pole and cylindrical rotor | difference between salient pole and cylindrical pole machine | difference between salient pole and round  Regarding salient pole machines, they are larger than cylindrical machines with Regardless of the differences between the two design, the applications and  On the other hand, the smooth cylindrical (round) rotors are characterised by Thus, salient pole rotors are well suited to low speed large dia machines and speed difference between the speed of the turbine and synchronous speed is  short axial length. The power rating of synchronous motors ranges between 150kW to 15MW. Most hydraulic turbines have to turn at low speeds (between 50 and 300 r/min) A large number of poles are required on the rotor; Hydrogenerator. of poles. The magnetic poles can be either salient (sticking out of rotor surface) or non-salient construction. between the machine's magnetic fields. In today’s tutorial, we are gonna have a look at Types of Synchronous Motor. Dec 21, 2018 · The salient pole type rotor is used for low and medium speed machines (less than 1200 rpm) and have the large diameter and small axial length. (B) 2. Each pole has a pole shoe around which the winding is wound. Outlines: Introduction Construction Working principle Types of Synchronous Machine Comparison A Cylindrical Rotor type Synchronous Generator Salient Pole Rotor type  6 Oct 2017 Lundin, U. The term salient means projecting. Define Pole Pitch? Answer : The distance between the centres of two adjacent poles is called pole pitch. Non-Salient pole generators are used for High speed operation. Jun 14, 2015 · Hence the effect of armature reaction in the case of a salient pole synchronous machine can be taken as two components - one acting along the direct axis (coinciding with the main field pole axis) and the other acting along the quadrature axis (inter-polar region or magnetic neutral axis) - and as such the mmf components of armature-reaction in a salient-pole machine cannot be considered as A salient-pole generator operates at lower load angles and is, therefore, preferred over cylindrical rotor generators for consideration of stability. in motorized MCCB's it will automatically charged the spring with the help of spring motor and ready for the next operation. Thus, a salient pole rotor consists of poles projecting out from the surface of the rotor core. 2. 2• Two types of rotor: [a] Salient pole rotor – magnetic pole stick out from the surface of the rotor • Its rotor poles projecting out from the rotor core. time difference between the occurrence of the null mark pulse and the occurrence of the next positive zero crossing of the power system voltage. Aug 06, 2016 · Some time they are also called as drum rotor . 6 b) In a three phase, 4 pole, 1000 rpm Y connected alternator has 60 slots with 8 conductor/slot for double layer winding. erefore,theproposedferrite generator has tangentially magnetized magnets mounted between magnetic pole shoes reinforcing the eld and is thereby a salient-pole machine. They are alternative known as "projected pole" type of rotors. m. Ans: D Q. They are generally used in lower speed electrical machines, say 100 Jul 12, 2013 · Electrical degree is used to account the angle between two points in rotating electrical machines. The stator of a three-phase synchronous motor normally has a sine  those of cylindrical rotor machines are distributed; (4) salient-pole generators These differences alter time constants, inductances, and transfer functions. Apr 27, 2011 · As these machines produces AC voltage, commutator is absent. (8. :3. The flux per poles 100 mwb. In a motor, E A lies behind Vf, and B R lies behind B net. The machine with such a rotor is called a cylindrical rotor or nonsalient-pole machine. This time difference is the offset or calibration time, shown as T cal in Fig. e. the phase difference between the two a phases, with 0 (meaning in phase) at the top and 1800 at. As the speed of the water turbine is slow hence more number of poles This is also called non-salient type or non-projected pole type or round rotor. In case of salient pole machines regulation is found out by applying Blondel’s two reaction theory. 14 Feb 2001 The first electromechanical rotating machines had salient poles and did not One part of a salient-pole motor was a magnet, a permanent magnet in most The Gramme armature was a ring or hollow cylinder of iron with the  Answer to Question 1 The typical types of rotors in a synchronous generator are cylindrical and salient-pole. One pole pitch is equals to 180 electrical degrees. 7. In synchronous machines, the rotor carries the field winding with the armature winding mounted on the stator. The inherent differences between salient and nonsalient electrical machines are evaluated for two permanent magnet generators with different configurations. Effect of Comparison of coverage for admittance and impedance protection schemes with  4. In medium and small size motors, dc field can be produced by permanent magnets. Dec 27, 2017 · Non-salient pole rotors are cylindrical in shape having parallel slots on it to place rotor windings. 4 Pole Motors. Mar 04, 2020 · There are mainly two types of rotors used in construction of alternator: Salient pole type. Now more emphasis and reliance is placed on controls to provide the required compensating effects with which we may be able to offset the reduction in stability margins inherent from above trends Oct 16, 2019 · In cylindrical rotor the poles are non-salient and in the rotor in which the pole face is out from it then it has salient (a pole which projects to the armature of an electrical machine) poles. turbo- alternators, which run at very high speeds. Smooth Cylindrical Rotor It consists of a smooth solid forged-steel cylinder having a number of slots milled out along its outer surface for housing field magnetizing field coils. number of pole pairs: Mechanical Degrees x Number of Pole Pairs In a four-pole generator (two pole pairs), each pole pair moves 360 mechanical degrees, so the total electrical degrees moved is: 360 x 2 = 720 The following illustrates electrical degrees in terms of number of poles: 2-poles = 360° electrical 4-pole = 720° electrical cylindrical rotors salient pole rotors either of the above none of the above ⇒ An alternator operating at lower voltage, for the same power rating, will be more efficient costlier less noisy larger in size ⇒ In an alternator short pitch coils are used to reduce the stray losses to reduce the size of the machine Jan 10, 2020 · The main difference between 2 Pole Motors and 4 Pole Motors is that 2 Pole Motors have a single pair of magnetic poles whereas 4 Pole Motors have two pairs of magnetic poles. 1 Salient Pole Type: This is also called projected pole type as all the poles are projected out from the surface of the rotor. Therefore the frequency of self-inductance alternation in a singly-excited machine is 2. Cylindrical-rotor machines are also known as non-salient pole rotor machine. In 3-point starter NVC is connected in series with field winding, while in 4-point starter NVC is connected independently across the supply through fourth terminal called (L-). In the round or cylindrical rotor case Jan 09, 2016 · The complex power output is. Jul 19, 2011 · Salient pole rotors are used in application with speeds from 100 to 1500rpm. The model obtained in this chapter is suitable for both isotropic (cylindrical) and anisotropic (salient pole) machines. Get Price Generator Types The two main types of generator are ‘turbo’ or cylindrical-rotor and salient-pole generators. The two main types of synchronous machine are Cylindrical Rotor and Salient Pole. The poles are not projecting out and the surface of the rotor is Difference between Cylindrical and Salient Pole Rotor. This standard includes synchronous motors and generators with two different rotor designs: a) salient-pole type rotors with solid or laminated poles; (also called cylindrical or nonsalient), with magnets surface mounted on a cylindrical iron core. The steam-turbine generator would have a cylindrical rotor of forged steel, with slots milled to the rotor on which the windings can be fixed. , suppression of harmonics, armature reaction-leakage reactance, Non-salient (or cylindrical) pole type; In salient pole type alternator, salient or projecting poles are mounted on a large circular steel frame which is fixed to the shaft of the alternator. We have  Our design team specialises in induction machines designs up to 20 MW and Combining the experience of its design team sharing over 100 years of design expertise Salient laminated pole synchronous machine electromagnetic design Cylindrical Solid Rotor End Cap Design; Cylindrical Single / Double End Rotor   21 Apr 2017 These type of machines have salient pole or projecting poles with concentrated field windings. Initial consideration will be given to cylindrical-rotor machines; the effects of salient poles are taken up in Sections 5. May 01, 2018 · Explained the difference between Salient Pole and Non Salient Pole rotor | compare salient pole and cylindrical rotor | difference between salient pole and cylindrical pole machine | difference Two Reaction Theory – Salient Pole Synchronous Machine Two Reaction Theory was proposed by Andre Blondel. 13) Define Pole Pitch? Pole pitch is defined as the distance between the Centres of two adjacent poles. Back EMF waveform. A typical example of slow-speed applications is a hydro power plant generator , whereas a steam turbine generator would represent an example of high-speed applications. The voltage taken by the fan during running has lagging power factor and in order to run the fan we need leading power factor. please specify the various points View How can I find the center of inertia frequency for multi-machine Cylindrical, round rotors, (also known as non salient pole rotor) are used for up to six poles. The sign convention for the mechanical power is when the speed is positive, a positive mechanical Cylindrical rotors are used in high speed electrical machines, usually 1500 RPM to 3000 RPM. Define Coil Span. Salient Pole Rotor The poles are made up of thick steel lamination to reduce eddy current heating loss and it is attached to a rotor by means of the dovetail joint. It is made of silicon steel lamination of 0. At first glance, these methods seem to work excellent at least with salient pole EESMs as the difference in the mutual inductance is very high . The projected poles are made up from laminations of steel. 7 show the rotors of three different types of synchronous machines: a cylindrical rotor, a salient pole rotor and a rotor with surface-mounted permanents. INDUCTION MACHINES:- ii) Rotor : Rotor is a field winding, the construction of which can be salient (projected pole) or non salient (cylindrical) type. . Cheaper compared to cylindrical rotor machines for speeds below 1000rpm Apr 28, 2016 · Salient Pole Synchronous Alternator: Salient pole Generators will have large diameter and short axial length Pole shoes cover 2/3 of the pitch Salient Poles are laminated in order to reduce eddy currents They are used in hydraulic turbines or diesel engines Salient pole generators will have typical speed about 100 to 375 rpm. They have more diameter and less axial length. Hi friends, this post is about objectives of synchronous machine. 6. Hydro-generator rotors are salient pole type. Substituting for / a from Eq. Jan 14, 2019 · The rotor can have cylindrical or salient pole construction. Actually salient pole rotor is a general case where as cylindrical pole rotor is special case. 6 Salient-Pole Synchronous Generator Stator Salient-pole rotor 7 Cylindrical-Rotor Synchronous Generator D 1 m Turbine L 10 m Steam Stator winding High speed This type of rotor called Salient-Pole and is usually used in low speed synchronous machines. Armature Reaction When the rotor is run, a voltage E is induced in the stator windings. In a motor the induced torque is in the direction of motion Select between a three-phase machine model or a five-phase machine model. What are the advantages of salient pole type construction used for Synchronous machines? Advantages of salient-pole type construction are : They allow better ventilation The damper winding (also known as ammortisseur) is mostly used in synchronous machine- in stator of synchronous generator and rotor of synchronous motor. The term salient means protruding or projecting. Cylindrical, round rotors, (also known as non salient pole rotor) are used for up to six poles. Cylindrical Rotor The cylindrical rotor is also known as a non-salient rotor or round rotor and this rotor is used for high-speed machines approximately 1500-3000 rpm and the example for this is a thermal power plant. The construction of non-salient pole rotor ( cylindrical rotor) is as shown in figure above. At ratings below 60 MW a gear box may be used to (i) salient-pole type and (ii) smooth-cylindrical type. This figure show that the generator only uses 2 poles. These allow better ventilation and also have other advantages over smooth cylindrical type rotor. Construction of a salient pole rotor is as shown in the figure at left. (i) Salient (or projecting) Pole Type It is used in low-and medium-speed (engine driven) alternators. alternators (i) salient-pole type and (ii) smooth-cylindrical type. Asked in Alternators , Electrical Engineering The salient pole type has poles that are physically separate, each carrying a concentrated excitation winding. Cylindrical rotors are used in high speed electrical machines ,usually 1500 Rpm to 3000 RPM . It is also defined as the number of slots per pole. Wound Rotor. What is the function of carbon brush used in D. Two types of rotors are used in alternators. Answer / vaseekaran. In large machines, field windings consist of rectangular copper strip wound on edge. 6 V. There is another type of rotor, which is shown in Figure 3. multiple choice questions on synchronous machines # 12 salient pole rotor B) smooth cylindrical rotor we have to know the basic difference between circuits Synchronous Machines. The relation between the pole, speed, and frequency is defined as. Unit 5 – SYNCHRONOUS MACHINES PART - A 1. They are invariably driven by a steam turbine or a gas tur-bine. d. NOTE: important difference between Ac and DC machines is that in AC machines the field winding is on the rotor while the armature is on stator. This type of rotor consists of a large number of projected poles (called salient poles), bolted on a magnetic wheel. May 30, 2015 · Smooth cylindrical(non-salient pole) type rotor is used in the turbo alternator. 5 to 0. Salient pole rotors are made for hydro plants, slower speeds where laminated construction is cheaper. The stator phases are represented by three sinusoidally distributed windings, displaced by 120 degrees. It is made up of solid steel. The rotor cylindrical or of the salient pole type. Synchronous Generator Protection and Control: A Collection of. 15. Q3. It is particularly used in high speed turbo generators. The rotor winding is provided on these poles and it is supported by pole shoes. Since all electrical machines operate with the help of magnetic fields, the electrical degree is accounted with reference to the magnetic field. (D) 6. Cheaper compared to cylindrical rotor machines for speeds below 1000rpm. MCCB is used where the system voltage is up to 600v ac. 51), the following expressions for real and reactive power output are obtained as Jan 09, 2016 · The complex power output is. The winding in this can be provided on the poles which are supported with the help of pole shoes. According to this theory two axes are recognized in the machine namely an axis along the polar axis called the direct axis or d-axis and an axis along the interpolar axis called the quadrature axis or q-axis which is 90 e displaced from the The salient pole structure is simpler and cheaper to manufacture than a cylindrical rotor. cylindrical rotor machines depending upon the type of construction used for the Therefore there is a great difference of peripheral speed at normal speeds and run. explains the parameter large difference in magnitude between different vari- ables in a similar  The inherent differences between salient and nonsalient electrical machines are The salient-pole, ferrite generator has lower maximum torque than the NdFeB A typical NdFeB generator is of round rotor type (also called cylindrical or  Cylindrical in shape having slots on the rotor surface where field windings are Non-salient pole in a four-pole machine, the rotor must turn at 1500 rpm. Cheaper compared to cylindrical rotor machines for speeds below 1000rpm why salient pole synchronous machine are more stable than the cylindrical rotor machines . This parameter is disabled when the Back EMF waveform parameter is set to Trapezoidal, or when the Rotor type parameter is set to Salient-pole. The principle of operation is the same as for any other generator. 31/10/2016· The main difference between the Cylindrical Rotor and Salient Pole classes of machine lies in the rotor construction. It is always 180 degrees electrical regardless of the number of poles in the machine. Pole pitch is the angular distance between two poles on a machine. Salient pole rotors have large diameter and shorter axial length. What are the essential features of synchronous machine? i. Jan 11, 2019 · Non-excited synchronous motors have steel rotors. Jul 18, 2012 · Salient pole generators will have typical speed about 100 to 375 rpm. These slots are covered at the top with the help of steel or manganese wedges. This consists of a core and the slots to hold the armature winding similar to the armature of a d. The salient-pole rotors have laminated steel mounted poles, and each pole has a ‘shoe’ around it used to wind the winding. cases, such investigations reveal no significant difference between the simplified model and the cant to the analysis of machines equipped with salient poles. It is known as the direct axis or d axis component. hydro turbines) • Cylindrical rotors• Cylindrical rotors – Used for high-speed applications (steam/gas turbines). Fig. 3. Define short circuit ratio (SCR) of a synchronous generator. Salient pole rotors are normally used for rotors Sep 24, 2019 · In Rotor Construction you have to study about the two types of Rotors i. salient pole machines, armature windings, integral slot and fractional slot windings, distributed and concentrated windings, distribution pitch and winding factors, e. Unformatted text preview: 10/21/2014 The difference between asynchronous and synchronous motors machine design The difference between asynchronous and synchronous motors Machine Design Leland E. We will explore factors a, b, and c and derive a machine model from them. The secondary output voltage will be (A) 3. The term, 'salient', simply means to 'stick out'. c. The neodymium based (NdFeB) permanent magnets (PMs) in a generator are substituted with ferrite magnets and the characteristics of the NdFeB generator and the ferrite generator are compared through FEM simulations. Non-salient-pole rotor: usually two- and four-pole rotors. Practically most of the synchronous motors use salient i. Salient pole Rotor. In the case of salient pole machines, however, the flux waves get distorted, especially along the interpolar gaps, as shown in Figure 2. Salient pole type 2. 14) Define Coil Span? smooth cylindrical rotor. The reason is there are slots in the rotor. This type of construction is in many ways complementary to that of the cylindrical rotor and is employed in machines having 4 poles or more. INDUCTION MACHINES:- d) The effect of salient pole rotor shapes. " N. Technical Papers GCCs for cylindrical-rotor and salient-pole-rotor generators. The structure of the synchronous machine based on the position of the rotor. 50), Equating the real and imaginary parts of Eq. The second type of synchronous motor i. The different between non-salient pole and salient pole based rotor of the generator. PRIYADHARSHINI AP/EEE - 3 - Construction of Rotor . Construction of synchronous machines The rotor of a synchronous machine is a large electromagnet. If we study the cylindrical rotor machine, then we will observe that the reluctance due to the air gap is higher than the reluctance due to the stator Construction of synchronous machines 1 Salient pole Machines: These type of machines have salient pole or projecting poles with concentrated field windings This type of construction is for the machines which are driven by hydraulic turbines or Diesel engin 2 Nonsalient pole or Cylindrical rotor or Round rotor Machines: These machines are Because of the magnetic coupling between the stator poles and rotor poles the motor runs exactly at synchronous speed. What Is an Alternator and How Does It Work. Efficiency The salient pole rotor used for low-speed machines approximately 120-400rpm. Select between the Sinusoidal (default) and the Trapezoidal electromotive force. Except in special cases its use is exclusive in machines having more than 6 poles. e di erence in saliency The basic difference between between 3-point and 4-point starter is the connection of no volt coil(NVC). 8 mm thickness to reduce eddy current losses and hence heating. How Cylindrical pole different from salient pole in asynchronous machine? 5. Low Speed (Salient Pole) This type usually consists of a ‘spider’ similar to that used in DC machines, on which the field poles and the field coils are bolted (see Figure 2(a)). Figure 1 Stator for a four-pole 415 V three-phase 350 kVA generator. Rotor. Explain the basic construction of synchronous machines. Non-salient-pole rotor: # of poles: 2 or 4. This type of rotor construction is employed for the machine driven by steam turbines. In the cylindrical theory, this mmf then produces a stator magnetic 3. 6 and 5. Different Methods Affect Winding Cost & Reliability When comparing manufacturing methods, not all stator windings offer comparable winding longevity or long-term value. Medium voltage stators are often used. 9. Smooth cylindrical rotor/ non-salient pole rotor. Electrical power is Construction of synchronous machines The rotor of a synchronous machine is a large electromagnet. supply through slip rings. Salient-pole rotor: four and more poles. 1), the rotor is not cylindrical and the air gap length depends on the angle with respect to the rotor axis. (2017) "Comparison of thyristor rectifier configurations for 1887 when Friedrich August Haselwander introduced the salient pole type. The limiting factor for the size of the rotor is the centrifugal force acting on the rotating member of the machine. Salient pole rotor; Nonsalient pole rotor or Cylindrical rotor; Question 32. e Figure-1 shows the two pole non-salient pole rotor. What Jul 12, 2013 · ii) Rotor : Rotor is a field winding, the construction of which can be salient (projected pole) or non salient (cylindrical) type. The poles mounted on the rotor are made of lamination's made of steel. Thus a salient pole rotor consists of poles projecting out Explained the difference between Salient Pole and Non Salient Pole rotor | compare salient pole and cylindrical rotor | difference between salient pole and c Free Educational Videos for Engineering Students Electrical Machines 2 Salient pole type rotors have large diameters and small axial lengths. Various Types of ROTOR Salient-pole Rotor Cylindrical or round rotor 53. Sep 28, 2019 · Salient Pole Type, and; Cylindrical Pole Type. Where, N = Speed of Motor in rpm. External force is required to start the synchronous motor as it has no starting torque. Briefly discuss the This paper presents a detailed analysis and comparison of large salient-pole synchronous generators (SPSG) with conventional slot distributed and fractional   Hydrogenerators and other salient pole machines consist of a rotating spider mounted on a shaft with field poles mounted on the spider rim. Q1. (D). It consists of a more number of poles so, rotor diameter is large. Windage loss as well as noise is less as compared to salient pole rotors. 8. ·The pole faces are so shaped radial air gap length increases from the pole center to the pole tips so that flux distribution in the air gap is sinusoidal in shape which will help to generate sinusoidal emf. In a generator, E A lies ahead of Vf, and B R lies ahead of B net. , n. There are mainly two types of Synchronous Generator from rotor construction point of view. The cylindrical rotor type has a uniformly cylindrical rotor that carries its excitation winding distributed over a number of slots around its periphery. The construction of non-salient pole rotor (cylindrical rotor) is as shown in figure above. Armature Reaction When the rotor is spun, a voltage EA is induced in the stator Salient-Pole Synchronous Generator. 4-pole motors and generators are Apr 27, 2011 · As these machines produces AC voltage, commutator is absent. It has no physical  The stator is similar to that of an induction machine consisting of a cylindrical iron frame with The difference is in the rotor, which normally contains an insulated winding connected through The rotor has salient poles without field windings. Cylindrical Rotor. The basic difference between motor and generator operation in synchronous machines can be seen either in the magnetic field diagram or in the phasor diagram. There are two types of rotor construction, namely the salient pole type and the cylindrical rotor type. Using the simplified generator power flow diagram it can be seen that the difference between mechanical input power and electrical ouput power is the combined rotational loss plus \(I^2R\) losses. Jul 22, 2011 · Salient pole rotors are used in application with speeds from 100 to 1500rpm. Cylindrical rotor type. \$\endgroup\$ – Marko Buršič Oct 5 '15 at 9:24 To know the difference between the Cylindrical Pole and Salient Pole Rotor, please read Difference between Cylindrical and Salient Pole Rotor. Winding loss as well as noise is less as compared to salient pole rotors . 3. What are the two classification synchronous machines? The classification synchronous machines are: i. Howev-er, in those machines the damper winding influences strongly the high frequency behavior of the machine. This type of construction is for the machines which  The torque equation for non salient pole machine is Te =-(P/2)(μoΠrl/g)(FsFr) sinλNm. 52. We can also describe it as the number of slots per pole. These machinery and devices technologies have A: As the speed of operation is low for hydro turbines used in Hydro-electric plants, salient pole type Synchronous generators are used. Salient Pole Type. Suad Ibrahim Shahl 3 Between DFIG and salient pole machines with the same power and speed, DFIG possesses larger dimensions and inertia and smaller air gap. As mechanical strength of salient pole type is less, this is preferred for low speed alternators ranging from 125 r. So a salient pole machine has field poles that stick out from the rotor. 7. This family of machines use a cylindrical rotor in which the field winding is housed in axial slots. Q2. The theory proposes to resolve the given armature MMFs into two mutually perpendicular components, with one located along the axis of the rotor of the salient pole. the prime movers or turbines used are of low speed such as hydraulic turbines like Pelton wheel, Kaplan, and Francis turbines. The motors start as induction motors Thus, the fundamental difference between a synchronous machine and an induction machine is that the rotor currents of the induction machine are induced while those of the synchronous machine are not. This is one of example of the structure for the non-salient pole. However, two sides of a coil are not always corresponding points under the adjacent poles and hence the coil has a span or pitch less than 180 degrees. Question 33. g. 16 The primary winding of a 220/6 V, 50 Hz transformer is energised from 110 V, 60 Hz supply. CONSTRUCTION OF SYNCHRONOUS MACHINES:-Salient pole rotor. Web. Rating. It provides some specific advantage to synchronous machines like – smooth starting and compensating the transient effect or unbalanced condition. Analytical methods of examining the steady-state performance of polyphase synchronous machines will be developed in this chapter. Explain the basic operating principle of synchronous generators. Then a logical explanation (my thougts) would be that cylindrical rotors are used in turbo generators with high speeds/forces and they are machined from solid steel. Since the flux must spread uniformly on rotor surface of DFIG its structure is uniform, cylindrical and laminated. The construction of synchronous motor is similar to that of a synchronous alternator. to 500 r. Jun 21, 2016 · The relationship between inductive component in the salient pole rotor winding and the fault location is similar to that of the relationship between the capacitive component and the fault location. Cylindrical rotors tend to be used in higher-speed machines in TWO REACTION THEORY is employed for the analysis of salient pole rotor synchronous machines. The inductance values between the rotor winding ends and the ground are measured from A to ground and from B to the ground. p = No. Freshers Electrical Machines Interview Questions 1. cylindrical rotor and salient pole machines and Section. The theory of the synchronous machine is well known, so only the basic model characteristics will be described here. It has a larger diameter and a smaller axial length. A wound rotor (rotating field) which has the same number of poles as the B. ELECTRICAL MACHINES -II Prepared by: P. The cylindrical pole rotor has the dc field winding embedded in them. Due to the presence of higher harmonics in the inductance  17 Jan 2020 Answer. Therefore Salient pole machines will have typically number of poles will be between 4 to 60. Salient-Pole Construction Machines like the ones illustrated in Figures 3. salient poles mounted on a magnetic wheel. The first type of synchronous generators are known as turbogenerators. 5 V. d) The effect of salient pole rotor shapes. Teschler Fri, 2013-01-04 00:33 The increasing importance of energy efficiency has brought electric motor makers to promote a variety of schemes that improve motor performance. In operation, the rotor is magnetized with the required magnetic poles in a manner analogous to that of an induction motor. A cross sectional view of a 3-phase, 2-pole, salient-pole synchronous machine is shown in Fig. 16 Mar 2016 Basics of Synchronous machines. The expression for torque and power is more complex in a salient pole machine, and the maximum torque typically occurs at a smaller value of δ. They are smaller in diameter but having longer axial length. As was shown in singly-excited machines , the frequency of the mutual-inductance wave was Z R . 2). Generator owners contemplating a rewind face multiple choices as they prepare their budgets and write specifications. If the field currend is provided by a pilot exciter and synchronous exciter, the power for the rotor \(I^2R\) losses is supplied from the mechanical Plug-in and Built-in dynamo in Figure 1(b) and Figure 1(c) are all salient pole machines, with large difference between d axis and q axis inductance, which can generate reluctance torque. Mar 02, 2017 · There are mainly two types of Synchronous Generator from rotor construction point of view. 20. In the electrical system there are 2 main types of mostly used motors first one is synchronous motor and second one is induction motor. [21] [22] The construction of synchronous motor is similar to that of a synchronous alternator. (C). 2. Furthermore In the case of a cylindrical rotor, an mmf wave of given magnitude. 3 have rotors with salient poles. 1 and 3. 51), the following expressions for real and reactive power output are obtained as Aug 28, 2018 · Now let us derive various equations for the power flow the cylindrical rotor alternator. However, many machines are designed with salient poles so it is desirable to modify the equation allow it be used for machines of this type. Thus a salient pole rotor consists of poles projecting out from the surface of the rotor core as shown in fig. The paper presents the analysis and the comparison of salient pole with field a cylindrical version of the machine make it possible to infer the performance of  than in the salient pole synchronous generator. 23 Dec 2014 Therefore from the literal meaning of Saliency one can guess that Salient Pole machines must have poles projecting outward. check out and comment if you have any doubts regarding this bits. 18 (curves 3). (i) Salient pole type (ii) Smooth cylindrical type (i) Salient (or projecting ) Pole Type The term salient means projecting. SALIENT POLE TYPE: Digital-computer program for design-analysis of salient, wound pole alternators (NASA technical note) It is used in low and medium speed alternators. Salient-pole alternators are generally used when the prime mover is a water turbine or a reciprocating engine. The rotor consists Jul 31, 2014 · Answer: 1. As the speed of the water turbine is slow hence more number of poles are required to attain the frequency. In normal (manually) operated MCCB's we have to charge the spring manually every time when it changes to off state. What is run away speed? 3. Salient pole generators will have typical speed about 100 to 375 rpm. A large number of poles are required on the rotor Hydrogenerator Turbine Hydro (water) D Sep 11, 2012 · The model development process is very similar to that of the induction machine, which is detailed in Chap. The effect of salient pole rotor shape will be ignored, and all machines in this chapter are assumed to have nonsalient or cylindrical rotors. The stationary field synchronous machine has salient poles mounted on the stator— the (cylindrical) rotors are utilized in two- or four-pole machines, and, very seldom,. Salient pole machines are lower speed machines and cylindrical pole machines are turbo speed machines. The poles are connected to the rotor shaft by means of dovetail joints. Cylindrical or round-rotor synchronous machine 1. What is common to all the members of this fam- ily is that the chronous electric machine, which is the type of machine all turbogenerators belong to. f. Salient pole type; Smooth cylindrical type. In order to derive various power equation for an alternator let us substitute voltage source E 1 equal to the excitation voltage (E f), voltage source E 2 equals to the terminal voltage (V t), inductive impedance of the above circuit equals to synchronous impedance (Z s) and Z s = r a + jX s. 1 Section of an alternator stator Fig. Default is 3. There are fundamentally two types of rotors used in synchronous machines: salient pole rotors and cylindrical (or non-salient pole) rotors (see The maximum power in cylindrical and salient pole machines is obtained respectively at load angles of (A). Oct 10, 2019 · Hello friends, I hope all of you are fine. equation Harmonics in generated e. 5. The armature, excited by alternating current, is wound in the stator of the machine, and the direct current field is wound on the rotor of the machine. For the best experience please update your browser. A. In which one pole pitch is equal to 180 electrical degrees. Ans: C Q. cylindrical-rotor (non-salient pole) machines and salient-pole machines Synchronous Generators Dr. WECS consist of many components and equipment&rsquo;s such as turbines, hub assembly, yaw mechanism, electrical machines; power electronics based power conditioning units, protection devices, rotor, blades, main shaft, gear-box, mainframe, transmission systems and etc. The machine speed is determined by machine inertia J (or inertia constant H for the pu machine) and by the difference between the mechanical torque Tm, resulting from the applied mechanical power Pm, and the internal electromagnetic torque Te. The unslotted portions of the cylinder itself act as the poles. ? Answer : Jun 04, 2015 · The poles and pole-shoes (which cover 2/3 of pole-pitch) are laminated to minimize heating due to eddy cur- rents. The construction of an AC synchronous generator of a salient pole type rotor is shown in the figure above. The field winding is excited by a separate d. cylindrical-rotor, machines The salient-pole machine has concentrated field windings and generally is cheaper than the cylindrical-rotor machine when the speed is low, (less than 1,500 rev/min). f m . Synchronous Motors Synchronous Motors are three-phase AC motors which run at synchronous speed, Synchronous motors have the following characteristics: A three-phase stator similar to that of an induction motor. In large machines field windings consists of rectangular copper strip wound on edge. The end view of a typical 6 pole salient pole rotor is shown below in the figure. Distinguish between lap winding and wave winding used in dc machine Lap difference of the machine mutual inductance in the direct- and quadrature axis [4]-[6]. 1. The salient pole type of rotor is generally used for slow speed machines having large diameters and relatively small axial lengths. Important Numerical Concept from Synchronous Machines a salient pole machine (such as Fig. Apart from high tech answers given above, one simple answer to your question- they are more Jul 17, 2018 · To know the difference between the Cylindrical Pole and Salient Pole Rotor, please read Difference between Cylindrical and Salient Pole Rotor. Smooth cylindrical type. – Minimum number of pp,oles is 2, so for 50Hz the maximum speed is Cylindrical vs. List the factors to be considered for separation of D and L for salient pole machines. Jun 02, 2017 · a) Explain the difference between cylindrical & salient pole synchronous machine. 4-pole synchronous motors and generators have solid rotors with salient poles while 4-pole induction motors and generators have squirrel cage rotors. Wind Energy Conversion System (WECS) plays an inevitable role across the world. synchronous machines 500 kVA and larger for use in petroleum, chemical and other industrial applications. Cylindrical rotor provides greater mechanical strength and permits more accurate dynamic balancing. The induced torque out of a salient-pole generator as a function of the torque angle δ is plotted in Fig. A motor is a device that transforms electrical energy into mechanical energy in the form of torque supplied through a shaft. Therefore, some considerations are shortened or removed. motorized MCCB's are used more that 630A rating. In the construction, the poles can be projected to the outside which is designed with the steel laminations. How the computer is aided design different from conventional design in the case of electrical apparatus. Starting Torque. The construction of the rotor is such that it forms a smooth cylinder. It functions embedded in the pole-faces to help damp out speed oscillations •Cylindrical/round rotors – 70% of large synchronous generators (150~1500MVA) – Distributed winding and uniform air gap – Large axial length and small diameter to limit the centrifugal forces – Steam and gas turbines, operated at high speeds, typically 1800-3600r/min (4 or 4. Squirrel Cage Rotor. The three phase generator rotor can be of two types: low speed and high speed. This includes the number of projected poles arranged on a magnetic wheel. For the working principle, you have to study the concept of Rotating Magnetic Field and then understand how the motor and generator will work. Salient pole rotor type 3. A comparison of diameter, length, number of conductors and turns and volume of copper Nov 22, 2019 · The round or cylindrical designs are used in machines operating on high speed, whereas the salient pole design is used in machines operating on slow or moderate speed. Cylindrical rotor motors have higher mechanical strength and are employed in high power and high speed applications; for other applications salient pole motors are preferred due to lower cost. 2 Rotor:There are two types of rotors used in alternators, 1. An illustration of a 4-pole salient pole rotor is shown below: but you should know the fundamental differences in the design of salient pole machines Machines with cylindrical rotors are typically found in higher speed higher power   The rotor is a moving component of an electromagnetic system in the electric motor, electric In generators and alternators, the rotor designs are salient pole or cylindrical. edu. (ii) Smooth Cylindrical Type. generator. Nov 24, 2017 · They are cylindrical type rotor and salient pole or projecting pole type rotor. Curve 4 is the first harmonics of armature reaction flux density with magnitudes 𝐵𝑎𝑑𝑚1 and 𝐵𝑎𝑞𝑚1. 0 V. The other component The main electomagnetic difference is a salient pole machine naturally has a varying air gap between the rotor and the stator, due to the pole saliency. In 2-pole motors and generators the rotors are cylindrical. In which the rotor turns in exact synchronism with the rotating magnetic field in the stator section. III. SM-1. It has a large number of projecting (salient) poles, having their cores bolted or dovetailed onto a heavy magnetic wheel of cast-iron, or steel of good magnetic quality (Fig. In cylindrical pole type alternator, the rotor is made of a smooth solid forged-steel radial cylinder having a number of slots along the outer periphery. Mar 28, 2015 · The effect of salient pole rotor shape will be ignored, and all machines in this chapter are assumed to have nonsalient or cylindrical rotors. It is used for steam turbine-driven alternators i. 5. (ii) Smooth Cylindrical Type: It is used for stem turbine-driven alternators i. The power loss of salient-pole generators can be approximated by Jan 01, 2018 · There are two main types of a generator like ‘Turbo’ or cylindrical-rotor and another one is salient-pole generators. The choice between the two designs (salient or nonsalient) for a Construction of a salient pole rotor is as shown in the figure at left. these motorized breakers are very plants, salient pole type Synchronous generators are used. Yes,Same theory can be used for the analysis for cylindrical rotor synchronous machines also. Cylindrical Rotors and Salient Pole Rotor. 3 Field of a sinusoidal distributed winding in a non-salient pole (cylindrical- rotor) SM. What is the difference between a salient pole and a . (i) Salient pole type (ii) Smooth cylindrical type (i) Salient (or projecting ) Pole Type . What are the merits of computer aided design? 2. Therefore from the literal meani. The problem will be approached here by empirical means since there is no known theoretical approach (see ref. Apr 17, 2020 · We’ll stop supporting this browser soon. But the rotor turns at the same speed and in synch with the stator rotating magnetic field. Non-salient pole or Cylindrical rotor or Round rotor Machines: These machines are having cylindrical smooth rotor construction with distributed field winding in slots. 4: The phasor diagram of a salient-pole synchronous generator. Explain the main differences between cylindrical-rotor synchronous machines and salient-pole rotor synchronous machines. Capacitor is used for both starting the electric fan and improving power factor. Mcq's on synchronous machines which are asked recently in various competitive exams like Gate , Upsc exams and so on. Both these types are synchronous machines in which the rotor turns in exact synchronism with the rotating magnetic field in the stator. What does the negative sign in the torque expression indicates? a) stator  Lecture 05 - Linear and Cylindrical Motion Systems · Lecture 06 - Systems Lecture 18 - Dynamic Equations of Salient Pole Synchronous Machine · Lecture 19 . 7: The developed torque versus torque angle for a salient-pole synchronous generator. Z R /p of frequency of the mutual-inductance of a doubly Salient-pole synchronous machine . Q4. The voltage drop of the. This rotor consists of a smooth solid steel cylinder, having a number of slots to accommodate the field coil. diagrams of a three phase non-salient pole (cylindrical rotor) synchronous salient pole synchronous generator; Phasor diagrams; Unity power factor power flows due to the phase difference between the Eo and Vt. Saliency simply means projection outward. Ferrites have much lowerremanencethanNdFeB. difference between cylindrical and salient pole machines

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