Pdf damping and synchronizing torques of salientpole. The individual field pole windings are connected in series in such a way that when the field winding is energized by the d. The rotor of alternator is designed in either of the two configurations. Owing to the highspeed, they have either two poles or four poles. One provides positive half of the wave form, the other is the negative half. The direct and quadrature axis components of current and reactance are same as defined earlier for the synchronous generators. When the rotor is excited with dc and rotated, the resultant field will also rotate so that sinusoidal voltages are generated in the 3 stator phases. Available excitation systems depending on alternator frames, are indicated in rating tables. Nonsalient pole the salient pole is most commonly used configuration.
Low voltage a lternators 4 pole 5245 en connection checks electrical installations must comply with the current legislation in force in the country of use. Salient pole synchronous motor electrical engineering. Apr, 2006 if we have a 30 amp alternator and weve revved it up to get 120 volts we can calculate the power available. Mar 04, 2020 an alternator is basically a type of ac generator. What is the difference between a salient pole and a.
Oct 26, 2016 the frequency shown by crutshow seems to me the right one for full wave rectifier 6 diodes as usually found in the cars alternator. Magnet size 45mm x 17mm x 4mm thickness with dual pole every surface my plan will use 8 pcs, give me suggestion if possible less than 8 pcs. This modification is made to cope with the very high power of the order of few 100 megawatts produced in an ac generator contrary to that of a dc generator. This structure aims to establish lower levels of saturation in the clawpole of lundell alternator. Tyler borysiak, myles moore, alex sklar, joshua lamb, stephen.
Well heres the deali am having trouble with my teleflex tach working correctly still on my 1974 50hp lark. When you need a 4 pole generator alternator, come to general power first. Shop our inventory of top quality brands or to speak with our generator experts. Voltage regulation characteristics of a synchronous generator. Frequency 8 poles x 12 cyclepole x 1500 revminute x 1min60 seconds. The method for calculating the two reactances of salient pole alternators with permanent magnet excitation has been developed. In the nonsalient pole pole machine,xd is nearly equal to xq. Where, f signifies the alternating current frequency and the p represents the number of poles. The projected poles are made up from laminations of steel.
A field coil is an electromagnet used to generate a magnetic field in an electromagnetic machine, typically a rotating electrical machine such as a motor or generator. There are mainly two types of synchronous generator from rotor construction point of view. The construction of an alternator consists of field poles placed on the rotating fixture of the machine. In this type, salient or projecting poles are mounted on a large circular steel frame which is fixed to the shaft of the alternator as shown in fig. The frequency shown by spec seems to me the right one for half wave rectifier 3 diodes. What are the advantages of a round rotor generator than a. Blondel two reaction theory salient pole alternators theory. Thus, x d direct axis reactance x q quadrature axis reactance i d direct axis component of i a. How winding is done in the salient type rotor of alternator. In a rotating machine, the field coils are wound on an iron magnetic core which guides the magnetic field lines. In most practical construction of alternator, it is installed with a stationary armature winding and a rotating field unlike in the case of dc generator where the arrangement is exactly opposite. In order to turn the alternator into a low speed generator all of the original alternator specifications will need to be measured.
Reducing the level of saturation in the rotor, lead to reduction of the losses in hysteresis, the. What do you mean by 2 pole or 4 pole power generators. Non salient pole the salient pole is most commonly used configuration. Since the regulation of an alternator depends on the load and the load power factor, it is necessary to mention power factor while expressing regulation. They are smaller in diameter but having longer axial length. For reasons of cost and simplicity, most alternators use a rotating magnetic field with a stationary armature. Two reaction theory salient pole synchronous machine.
Alternator and poles electronics forum circuits, projects. Pdf this paper presents the finite elements analysis fea of a salient poles synchronous generator. Jun 22, 2010 i purchased a magnetic pole detector to identify the poles of some magnets and tried to see if i could detect the changing magnetic field of the alternator in my car while it was running by placing the pole detector on a specific point at the stator, but the pole detector didnt do anything, didnt indicate a changing field. Occasionally, a linear alternator or a rotating armature with a stationary magnetic field is used. In order to prevent the peripheral speed from exceeding the safe limit, the diameter of the rotor is kept down. Opening the alternator reveals a large cylinder with triangular finger poles around the circumference. Both passes make current flow in one direction round the loop. The north pole of the magnet passes the top of the loop as the south pole passes the bottom of it. The slow speed salient pole alternators are ventilated by the fan action of the salient poles which provide circulating air. Oct 07, 2015 difference between salient pole and non salient pole smooth cylindrical rotor duration. Shop for quality 6 pole generator ends from general power. This was already done in ervin carrillos senior project and can be located in the. Salient pole synchronous generator analysis is made through the tworeaction theory outlined below.
Smooth cylindricalnonsalient pole type rotor is used in the turbo alternator. Analysis of nonsalient pole synchronous generator using phasor. One of the two types of rotors typically installed within large generators is the salient pole rotor figure a. Consequently, a four pole generator could output twice the voltage of a two pole generator, a six pole generator could output three times the voltage of a two pole. The alternator generates a stronger voltage that builds up after buildup the field is supplied by rectified voltage from stator with brushes direct connected dc generator smaller generator to excite the field coils brushes to excite the rotor variation. Actually the difference between 2 pole and 4 pole ac alternators is the speed at which they operate, in europe we typically use 50hz per second or cycles and north america 60hz as the frequency, a two pole alternator has to operate at a higher spe. The rotor rotates in the stator, and the field poles get projected onto the rotor body of the alternator.
Pdf study of salient poles synchronous generator by finite. Why are salient pole rotors used in hydro generators. Designed, built and tested in the motor factory, solid salient pole rotors are suitable for applications requiring long duty cycles. This rotor has solid poles and a striponedge field winding.
Alternating poles in the stator of an alternator physics forums. Non salient or cylindrical pole type salient pole type. This paper deals with an indetail analysis of a salientpole, woundfield, three phase synchronous generator operating in singlephase. Jul 15, 2016 the rotor of alternator is designed in either of the two configurations. By increasing the number of pole faces surrounding the gramme ring, the ring can be made to cut across more magnetic lines of force in one revolution than a basic two pole generator. Explain the constructional details of alternator in. For the same size, the rating is smaller than the cylindrical type. An alternator is an electrical generator that converts mechanical energy to electrical energy in the form of alternating current. In a round rotor machine, armature current in phase with field induced emf e f or in quadrature at 90 to e f produces the same flux linkages per ampere as the air gap is uniform so that the armature reaction reactance offered to inphase or. When designed as a generator, large salientpole machines are driven by. In this paper, various performance equations are derived from phasor diagrams of a three phase nonsalient pole cylindrical rotor synchronous generator of. Non salient pole generators will have smaller diameter and longer axial length they are used for high speed operation typically speed will be 1500 and.
The main components of an alternator are the rotor, the stator, and the rectifying circuit. Nonsalient pole generators will have smaller diameter and longer axial length they are used for high speed operation typically speed will be 1500 and. An 8 pole machine produces 4 full cycles per revolution. We knew that in non salient pole type alternators the air gap is uniform. The analysis of salient pole synchronous motor is based on the blondels two reaction. I purchased a magnetic pole detector to identify the poles of some magnets and tried to see if i could detect the changing magnetic field of the alternator in my car while it was running by placing the pole detector on a specific point at the stator, but the pole detector didnt do. Salient pole rotors usually have a large number of poles usually 6 or more.
I have a 85hp older evinrude also and i counted the blue widings under the 85 and sure enough there are 6 on each side under the flywheel so its a 12 pole for sure as even the tach in the boat is marked 12 pole on the backnow everybody has. If we have a 30 amp alternator and weve revved it up to get 120 volts we can calculate the power available. The poles move away, and current stops flowing until the south pole reaches the top and the north pole the bottom. A further important feature is the alternator or rotor system e. The component f d is either magnetizing or demagnetizing. The field poles are made to rotate at synchronous speed n s 120 fp for effective power generation.
The rotor winding is provided on these poles and it is supported by pole shoes. Salient pole synchronous machine two rection theory. It consists of a coil of wire through which a current flows. Three phasesingle phase reconnectable avr regulation 14 to 44 kva. Construction of a salient pole rotor is as shown in the figure at left. Two reaction theory of salient pole synchronous alternator. I have run into something i dont understand while working with an alternator. Solid salient pole motor synchronousmotor ge power. In principle, any ac electrical generator can be called. Turbo alternator construction diy electrical electronics. Damping and synchronizing torques of salientpole generators with accurate representation of saturation article pdf available in ieee transactions on energy conversion 101. This makes them suitable for low speed high torque prime movers, such as low speed diesel engines or hydroelectric turbines. The two main types of synchronous machine are cylindrical rotor and salient pole. Tyler borysiak, myles moore, alex sklar, joshua lamb.
Frequency 8 poles x 12 cycle pole x 1500 revminute x 1min60 seconds. Low oltage alternators 4 pole tal040 tal042 tal044 10 to 150 kva 50 hz 12. Clearer drawing of the 10pole 12 coil design hugh piggott. The shaft and pole bodies are of integral construction, produced from a single normalized carbon steel forging.
Alfa electricals offering silent pole type alternator. On the theory of salient pole alternators with electromagnet. Owing to the presence of the magnets, the direct axis armature reactance has been. Difference between salient pole and non salient pole smooth cylindrical rotor duration. Non salient pole rotors are cylindrical in shape having parallel slots on it to place rotor windings. The low speed alternator design will take an alternator, and through a few tweaks of the generator, will be usable for low speed applications. Alternating poles in the stator of an alternator physics. Our generator end product lines are exclusively composed of brand new, 100% original products.
A basic alternator is made up of a series of alternating finger pole pieces placed around coil wires called field windings that wrap around an iron core on the rotor shaft. Sell or buy used industrial equipment in the field of electricity production, transmission and distribution. The d axis component of the armature mmf f a is denoted by f d and the q axis component by f q. In the non salient pole pole machine,xd is nearly equal to xq. This two reaction theory was given by professor andre blondel so it is named as blondel two reaction theory. In salient pole type of rotor consist of large number of projected poles salient poles mounted on a magnetic wheel. The construction of non salient pole rotor cylindrical rotor is as shown in figure above. Lo oltage alternators 4 pole lsa 40 10 to 20 kva 50 hz 12. The component f q results in a crossmagnetizing effect.
Since the location of e0 is unknown id and iq cannot be found which are needed to draw the phasor diagram. The synchronous electrical generator also called alternator belongs to the. By the definition, synchronous generators produce electricity. The different alternator sizes are identified by a letter of the alphabet, and increase in alphabetical order. Due to the uniform air gap, the field flux, as well as armature flux vary sinusoidally in the air gap. Speed and frequency in an alternator, there exists a definite relationship between the rotational speed n of the rotor, the frequency f of the generated e. This makes current flow again, but in the opposite direction. Salient pole synchronous generator power angle curve.
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