(mechanical for motor, electrical for alternator) Now, the difference between a synchronous machine and an induction machine is based on how the rotational magnetic field is utilized. On the left we see the most simplistic scenario: 2-pole rotor and a 3-pole stator. However, the permanent magnet synchronous motor has a smaller volume and a lighter weight. Slip is the difference in speed between the rotor speed and synchronous speed of the rotating stator field; as the load increases in a motor, slip increases and the motor slows. The induction generator has numerous limits. The stator carries a 3-phase winding while the rotor . But in this case theres no more rotating magnetic field around the bars, as they move with the same speed. For North poles. The colours indicate each phase, The. A synchronous motor is costlier than an induction motor of the same output and voltage rating. Here we will discuss the Difference between Induction Motor and Induction Generator. Principle. All Rights Reserved. The synchronous speed of a stator rotating magnetic field depends on the supply frequency and the number of poles for which stator winding is wound. The synchronous motor has more power efficiency due to the unity or leading power factor. The synchronous motors always run at a constants speed which is called synchronous speed. An Induction Motor is an AC electric motor in which the electric current in the rotor is produced by electromagnetic induction from the magnetic field of the stator winding. In power stations, generators are used to generate electricity. What are the differences between the Induction motor and the Synchronous motor? The induction motor is mostly used in industrial applications. Its stator winding is energized from an AC source. This rotating magnetic field will induce a current in the squirrel cage bars based on electromagnetic induction. Use the Right Hand Rule to see the magnetic field. The Shaft of the motor is run by the magnetic force produces between armature and field windings, while in the case of . It is self-starting the motor. The induction motor works on the principle of 'Electromagnetic Induction'. As Mr. Bhupendra Desia rightly explained about the differences.Induction generator produces electricity by having the difference in the rotor speed (Nr) and the synchronous speed (Ns) is that for . Practically it is not possible for stator poles to pull the rotor poles from their stationary position into magnetic locking conditions. (especially three-phase induction motor). It is essentially a coil where you start rolling up a wire at one end and finish it up the other. There are various types of motors available as classified below. Based on the number of rotor poles we can distinguish between: In the above example we had an electromagnet as a rotor that had a North and a South pole (2 poles). What techniques are available to start a synchronous motor? (Generators) A Synchronous Motor operated backwards work as a generator. This happens so fast that what we witness in real life, is that the machine rotates a bit slower than the synchronous speed. Lets see what the biggest difference is. It has unity or lagging or leading power factor. Synchronous motor. In the reluctance motor, the rotor has projecting poles that resemble individual teeth. The fundamental difference between these two motors is that the speed of the rotor relative to the speed of the stator is equal for synchronous motors, while the rotor speed in induction motors is less than its synchronous speed. Your other four fingers will indicate the direction of the magnetic field. Figure 8: Construction of a Synchronous Motor. 3. A Synchronous Motor operated backwards work as a generator. Alternating Current is fed into the winding. If you have any queries, drop me a message in the comment section below. The rotating magnetic field induces a current flow in the squirrel cage bars based on the law of electromagnetic induction. 2. What is a Junction box, and its applications? Normally, for a solenoid (coil) one end is N and the other S with 180 between them. It can be constructed with wider air gaps than induction motors which makes it better mechanically. The turn is also in the opposite direction. Note, it is heading in a different direction inside the cage than outside (blue arrows). The construction of the induction motor is relatively easy. Types: DC motor and AC motor. Based on the number of rotor poles we can distinguish between: . Very easy to understand the way you compare both motors. . It is basically the same as induction motor. In this post, we are learning the difference between the two types of alternating currents (AC) motor. The synchronous motor requires the DC excitation system (or prime mover) to start the motor (i.e. One feature of the synchronous machine is that it has two electrical sources, one for the rotor and one for the stator. The speed is always less than synchronous but never synchronous. We came up with the basic definitions of what are induction and synchronous generators . Essentially, we have a coil that is wrapped around the rotor. I am also a technical content writer my hobby is to explore new things and share with the world. A synchronous motor can be operated with lagging and leading power by changing its excitation. It has unity or lagging or leading power factor. Designed and Developed by, Difference between Induction motor and Synchronous motor. Initially the motor is wired in a star configuration, where the phase voltage is smaller than the line voltage, next, when the motor is running it is switched to a Delta config. It is used in constant speed application; the speed of the induction motor can be variable. Figure 1: Construction of a 3-phase induction motor. The same four-pole motor operating on a 50 Hz grid will have a . As the current alternates, so does the direction of the magnetic field and poles. Definitely, I will try to publish and share more tutorials and useful technical kinds of stuff. In a generator, on the other hand, the armature or windings of wire spin inside a fixed magnetic field to generate electricity. Hope this will help you for the preparation of the exam or interview. 1. Electric motors, generators, alternators and loudspeakers are explained using animations and schematics. The Synchronous Motor requires the DC excitation system (or prime mover) to start the motor (i.e. 12) Speed, in RPM (revolutions per minute). An induction or asynchronous generator is an electric induction motor driven at speeds above its synchronous speed. means it is going in the page, whereas the dot means coming out. Different structure settings. In the supply system of the induction motor, stator winding is linked by an AC source. . In a 4 pole scenario the N and S poles change every 90. s = (ns-n) / ns. Connected Supply. Synchronous motors are having better efficiency, than induction motors. 04. Your email address will not be published. A difference between an induction generator and a synchronous generator is that an inductive generator creates an electric field using inductive coils, while a synchronous generator uses a . A single-phase induction motor is used for the mixers and grinders. ; It has a solid armature, or squirrel cage, that is an electrical short circuit.When the current is connected, the machine will start turning like a motor at a speed that is just slightly below the synchronous speed of the rotating magnetic field from the stator. document.getElementById( "ak_js_1" ).setAttribute( "value", ( new Date() ).getTime() ); document.getElementById( "ak_js_2" ).setAttribute( "value", ( new Date() ).getTime() ); New users enjoy $54 free coupons after signing up at JLCPCB successfully, $54 coupons can also apply to 3D printing orders, for 3D printing special offer, it gets started at $1, Difference between cell splitting and cell sectoring, Differences Donor and Acceptor Impurities in Semiconductor, Wio-E5 and FREE Seeed Fusion PCBA Prototypes Campaign, DETAILED GUIDE TO GROUNDS, EARTH, AND GROUNDING ELECTRONICs, The AC motor that used the occurrences of the electromagnetic induction to generate the current and flux in the rotor to generate torque is familiar as the induction motor. It runs at less than 1500 rpm. But the induced current itself in each bar will have its own magnetic field that will repel the stators field, thus, creating a force. An induction generator produces electrical power when its rotor is turned faster than the synchronous speed. Electricity is employed in the motor, but the generator creates the electricity. It has to be run up to synchronous speed by any means before it can be synchronized to AC supply. This works the same principle as in induction motors. Electrons, as they move in a wire, create a magnetic field. The induction generator always rotates at more than synchronous speed (Nr>Ns). Required fields are marked *. A synchronous motor can run . MV = High Efficiency +1~2%. This conductor is rolled up in a coil. The output frequency of an asynchronous generator is slightly (usually about 2 or 3%) lower than the frequency calculated from f = RPM x p / 120. Current, which is the flow of holes or in other words the absence of electrons, flow in the opposite direction. An induction generator produces . (especially three-phase induction motor) 05. Ohms Law Statement | Formula, Limitations and Applications, The Beginners Guide to Voltage | Potential Difference | EMF. Copyright 2019 Engineering Scribbles | ALL RIGHTS RESERVED, Electronic & Electrical Engineering Basics. This generator workings in a motorized way as the speed of revolution of the generator is upper than the synchronous speed. When we have the same . What is a soft starter? In a motor, current is supplied to the armature winding. This is all about the difference between synchronous and induction motors. Figure 4: Squirrel Cage (part of the rotor) in an Induction Motor. Requires DC excitation supplied from external sources. I always thought mixers and grinders used universal motors. A synchronous motor is costlier than an induction motor of the same output and voltage rating. These are very important topics in electrical engineering. What are slip and slip speed in an induction motor? An induction motor operates only at a lagging power factor. Fundamentals: (1) When a three-phase asynchronous motor is connected to a three-phase AC power supply, a three-phase magnetomotive force (stator rotational magnetomotive force) generated by a three-phase stator . In these articles, we tried to provide all the necessary information regarding the difference between an Induction Generator vs. Synchronous Generator. aspen school district calendar difference between slip rings and commutator. What are factors need to be considered while choosing a motor? It is the stationary part of the Induction Motor which consists of a series of wire windings, The stator is made up of a steel frame which supports a hollow cylindrical core, The core consists of stacked laminations that have evenly spaced slots where the stator winding is placed. Also, here is a good video that explains more about a Star & Delta starter. Only stator is given 3 phase AC supply. Speed of Synchronous motor is independent of the load and always runs at synchronous speed. Synchronous motors can be classified into two types based on how the rotor is magnetized. The power factor is very low during light load conditions. The power factor of a synchronous motor can be adjusted to lagging, unity or leading by varying the excitation, whereas, an induction motor always runs at lagging power factor. Use the Right Hand Rule to see the magnetic field. The stator winding of Induction Motor is energized from an AC source. Normally, for a solenoid (coil) one end is N and the other S with 180 between them. The hand help us determine the flow of current based on the moving magnetic fields direction (where the arrows point) and motion (which way does it move). Motor is a device that used to transform electrical energy into mechanical energy. If the frequency of the A.C. supply is Hz and the stator is wound for the P number of poles, then the speed of the rotating magnetic field is synchronous. A three-phase synchronous motor is a doubly excited machine, whereas an induction motor is a single excited machine. The synchronous motor works on the principle of the 'Magnetic Locking'. Different types of motors are used in industries and homes according to . Both of these devices are working on the principle of Faraday law of electromagnetic induction. A motor is a device that converts Electrical energy into Mechanical energy. The rotor speed of the induction motor is continually less than the synchronous speed, so the motor continually runs at a speed fewer than the synchronous speed. Synchronous speed be contingent on the number of poles of motor and frequency of input voltages. Answer (1 of 9): The same as the differences between a synchronous motor and an induction motor, because they're the same things. Schematics and operation of different types of motor. The speed is independent of load. So, in a 2-pole scenario, the rotor rotates 50 times per second to generate 50Hz electricity. Rao Kattoju, Thank you very much, Veerabhadra for your kind words. 1. The hand help us determine the flow of current based on the moving magnetic fields direction (where the arrows point) and motion (which way does it move). They operate at a more simplistic principle and theyre also cheaper to manufacture. Using Damper Winding as a Slip Ring Induction Motor (Synchronous InductionMotor). 1. Speed. Hence synchronous motor rotates at constant speed i.e., synchronous speed. Difference Between AC and DC Motors; Difference Between AC and DC Generator; Synchronous Motor. The difference between them begins with the way the magnetic field of the rotor interacts with the stator. In a generator, current is produced in the armature winding. Hold a wire in your hand. Synchronous motors are costlier, almost 25% of the motors cost goes to rotor windings, but induction motors are cheaper. The speed is always less than synchronous irrespective of the load. This works the same principle as in induction motors. This force will make the cage rotate. Key Differences Between Motor and Generator. If the conductor is part of a closed circuit, this force will move electrons and current will flow. The motor cant use in such applications where high starting torque is necessary. A Synchronous motor is a double exciting machine i.e., two electrical inputs are provided to it. Thanks, Mathew Varghese. Induction machines, also called asynchronous machines are slightly lagging behind the synchronous speed. What is a synchronous capacitor? It is used for power factor correction, constant speed load service. It is more efficient than an induction motor of the same output and voltage rating. It is self-starting the motor. When an Induction Motor is connected to 3-phase power, the magnetic field starts to rotate instantaneously. - Synchronous motor required DC excitation to its rotor. The trick is to disconnect the slip rings initially while the cage is in action, next, once the rotor is spinning, we connect them back and the fields will lock. Hello, readers welcome to the new post. Its speed cannot be varied without sacrificing some of its efficiency, Its speed decreases with the increase in load. The stator contains slots for a uniformly distributed field winding in an induction motor while the rotor carries the armature winding. The induction motor always runs at speed less than its synchronous speed. While Generators is a device that are used to convert mechanical energy into electrical energy. Whereas Induction Motor is a single excited machine and its winding are energised from an AC source. The direction of the magnetic field always goes from North to South, so referring to the magnetic flux lines outside the loop, we can draw in the N & S poles. This leads to the rotor to slow down. When an Induction Motor is connected to 3-phase power, the magnetic field starts to rotate instantaneously. While Generators is a device that are used to convert mechanical energy into electrical energy. Because their rotors never run with the synchronous speed. Your our thumb will point to the direction of current flow. More about Induction Motors. The magnetic field always points, In the above diagram, the North and South poles will change positions 50 times a second. How to make the single-phase Induction motor self-starting? Induction motor. The induction motor does not require an excitation system to start motor. In 3 phase Induction, a motor Rotating Magnetic Field (RMF) is produced by supplying currents to a set of stationery winding (or) stator with the help of a 3 phase power supply. The cage will start to rotate due to the Lorentz Force. An induction generator is frequently used in hydel power plants, wind energy production, and they have the ability to cut the higher-pressure air to less pressure since they have the aptitude to reestablish power with the coolest way. The Induction motor is also known as asynchronous motor because its rotor rotates at a speed less than the theoretical synchronous speed of the motor. The 2-pole DC electromagnet in the diagram has a fixed N and S poles and they lock with the rotating N & S poles of the 3-phase magnetic field. Hold out your hand. Motoris a device that used to transform electrical energy into mechanical energy. Induction generator takes reactive power from the power system for field excitation. 4. In the first picture, one side of the rotor is N and the other is S. In the 4-pole case, the opposite side of the North pole is another North pole. 3. It can be used as a synchronous condenser for power factor improvement. Thus, we can draw the N & S poles. In a 4 pole scenario the N and S poles change every 90. This force will make the cage rotate. 3. Power factor is lagging in induction motor and unity in synchronous motor. AC machines (mostly synchronous machines) convert this rotation into 3-phase electricity. Also covered the advantages and disadvantages of these two AC motors. Yes, it can run, but a phase-splitter will be essential in this case. In a synchronous generator, the waveform of generated voltage is synchronized with (directly corresponds to) the rotor speed. Inputs to the machine . What does a soft starter do? 7. . The idea is that this time the rotating shaft (. As we know rotating magnetic field rotates with synchronous speed when two opposite poles of the rotor and RMF locked rotor also rotates with the same speed of RMF in the direction of the rotating magnetic field. We define the North and the South poles based on the magnetic fields direction outside the cage. The rotor is not given any supply. So, in the case of synchronous motors, instead of generating a Lorentz Force, we lock the poles of the stators DC electro-magnet with the rotating 3-phases field. The motor will operate in DC and AC power supply. Think about it, this way the rotor doesnt need to rotate crazy fast. An Induction Motor is also known as Asynchronous Motor. As the N & S poles rotate, so will the current change direction in each bar. Since it does not have exterior excitation circuitry and it cannot produce reactive energy (Q). On the right, we have a 4-pole rotor with a 6-pole stator. The induction motors are the types of asynchronous motors. Runs lower than synchronous speed. Generally used alternating current motors are induction and synchronous motors. Similarly, it also consists of two main parts- the stator and rotor. The synchronous motor working principle is magnetic locking, when two, unlike poles, are brought near each other, if the magnets are strong, there exists a tremendous force of attraction between those two poles, in that case, the two magnets are said to be magnetically locked. In this post, we will discuss the detailed difference between the induction motor and induction generator. We further classify it into three types; they are the induction motor, synchronous motor, the linear motor. An induction motor is a single excited machine. The synchronous motor always runs at Synchronous speed Ns. Fan, blowing fan, a dryer is an example of the synchronous motor. Mostly used in Single phase Induction motor. At high loads, the power factor of the induction motor becomes very poor. A Single-phase induction motor is not self-starting, It requires some support for starting. Save my name, email, and website in this browser for the next time I comment. A regular AC induction motor usually can be used as a generator, without any internal modifications. It means that only a single source . This means the rotating magnetic field will be super fast compared to the stationary cage and will generate a huge initial current. This motoris cheaper than the synchronous motor. Synchronous Motor always runs at synchronous speed, and the speed of the motor is independent of load, but an induction motor always runs less than the synchronous speed. Induction machines are very commonly used. Thumb shows the direction of the current and the fingers indicate the direction of the magnetic field. What is the obvious physical difference between the induction and synchronous motors? These are AC generator (Synchronous & Induction generator) and DC generator (Separately excited & self-excited). difference between slip rings and commutator. The first generator was invented by Michael Faraday in 1831. for the rotor rotating). Note, it is heading in a different direction inside the cage than outside (blue arrows). @2020 - automationforum.co. What is Induction Motor (or) Asynchronous motor? For Synchronous motor, relative motion is not required in between the stator and rotor. It is very simple. ISO 9001:2015 (Quality Management System), ISO 14001:2015 (Environmental Management System), ISO 45001 : 2018, OEKO-TEX Standard 100 What we have is a coil. Why NPN transistor is more used over PNP transistor? This means for example the North pole of the electromagnet will attract the South pole of the rotating magnetic field. Its armature winding is energized from an AC source and its field winding from a DC source. "f" is the frequency of the output of the generator. Many times you will be asked to compare these two types of motors. Synchronous motors can achieve efficiencies of >90% in some cases and are generally more energy-efficient than induction motors. The synchronous electric motor which works on AC current is used in domestic grinder, the motor is winding is done with copper wire to produce a magnetic effect to the rotor, the rotor, in turn, revolves with a high speed as per the capacity and power utilized by them. We can even have more poles. Can a 3phase motor be run on a single-phase line? The brushes only touch the rings. - Speed of synchronous motor is constant at all load. The Lorentz Force will be symbolised by an arrow that come out from your palm. According to its working principle, it is also called "induction generator". Its speed is independent of the load. This is comparatively more efficient than an induction motor, Its stator winding is energized from an AC Source, Its field winding is energized from a DC source and Armature winding is energized by AC Source. Since there is a sort of transformer action between the cage and the stator windings, this rush of current will also reflect in drawing a massive current from the 3-phase supply. Although, in real life it looks more like in Figure 6. I am a professional engineer and graduate from a reputed engineering university also have experience of working as an engineer in different famous industries. This is great for size-constrained applications and is a reason to choose a synchronous motor over an induction motor. It consists of copper or aluminum bars embedded in the semi-closed slots resembling a squirrel cage. To come across this issue, we use the Star-Delta Starter method. Only an AC source is required to operate, it doesnt require DC excitation. The Permanent Magnet Synchronous Motor is mainly . 5. It is also is recognized as the. Induction generators use an armature to create an electric field that causes Starter motors to run. Based on the source nature, the electric motor is of two types. Hold a wire in your hand. Think of a steam or wind turbine, where the blades are attached to a rotating shaft. V Curve of a Synchronous Motor. An induction motor is a singly excited machine, that is, its stator winding is energized from an AC source. The electricity is supplied from brushes to the slip rings. Dont forget, this is one wire. The magnet needs power. The motor that converts the alternating current into mechanical power by using an electromagnetic induction phenomenon is called an AC Motor.Mainly an AC motor classified into two types. Although, when there is a current in a wire (or bar in our case), the current will induce a magnetic field itself. The ac voltage is . Working Principle of Synchronous generator : The alternators work on the principle of electromagnetic induction. I work and write technical tutorials on the PLC, MATLAB programming, and Electrical on DipsLab.com portal. The rotor will rotate only at one speed in the synchronous generator unlike the induction motors. For a typical four-pole motor where there are two pairs of poles on a stator operating on a 60 Hz electrical grid, the synchronous speed is 1800 rotations per minute. Difference between synchronous generator and induction generator. To know more about the Star & Delta config, check out this earlier post. Your email address will not be published. Real power is being supplied by prime mover input and reactive power is absorbed from the system. 5. The cage has a rotating field around (which is from the 3-phase windings in the stator). Flemings Right Hand Rule. All Right Reserved. What if we used the same wire and wrap it around 4 poles instead? Intuitively, it makes sense that as more power is required by the mechanical load on the motor, one or both of the magnetic fields must get stronger. In the case of a 4-pole setup, the rotor only has to turns 25 times to generate the same 50Hz. The same four-pole motor operating on a 50 Hz grid will have a . Here, Im comparing synchronous motor and asynchronous motorwith their specifications, functions, applications, and examples. This is the Right Hand Rule. It is always less than the synchronous speed. The motor is cheap, especially cage rotors and maintenance-free. 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. Construction of Induction Motor is relatively easy. Induction generator is a motor that uses electromagnetic induction between the rotors to induce current in the rotor to achieve electromechanical energy conversion. It cant be started under loaded conditions; its starting torque is zero. It consists of Three-phase winding in the rotor, Rotor windings are uniformly distributed and are connected in star or Y shape. Control voltage at the end of the transmission line by varying the excitations. Thank you for explaining the differences between Induction motors & Synchronous motors in simple terms. Application: Used in pumps, compressors, paper mills, textile mills, lathes, Drilling machines industrial drives. This field induces a current in the bars. Since, the field is excited by the power system, the synchronous generator can deliver only real/true power but absorbs the reactive power.