Explanations about how does a single phase induction motor works as a generator ?
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You need to mechanically generate motion to turn the shaft of the motor/generator at the speed specified on the name plate. Say 1800rpm for a induction motor would then generate the given voltage at 60Hz.\n\nIt is important to maintain this motion otherwise the frequency will vary.\nThe torque to maintain this motion is related to the load on the motor. So a 1 hp motor is about 746 watts. So for a 10kw turbin you will need a 2 x 15HP motor or 30HP motor due to a 50% efficiency factor for the maximum load. Most of the mechanical energy goes into heat.
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We do use electromagnetic fields to transfer current. Every day.\n\nIt's a necessity in the power industry! The device is called a "transformer".\n\nThe major limitation for use is dependent on both the strength of the originating magnetic field and the distance to the conductor which is have current induced. The resultant current is less, in proportion to the square of the distance between the conductor and the field source. It is also less in proportion to the magnitude of the originating field.\n\nThe actual induced current is achieved by passing a conductor through a stationary magentic field (in which case the frequency of the current waveform is proportional to the speed of the conductor's movement), or by oscillating the magnetic field at some frequency compared to a stationary conductor (in which case the frequency of the current is the same as the magnetic oscillation frequency), or by a combination of the two.\n\nBelieve it or not, this is exactly how rotating electrical machines work. Alternating Current machines vary the magnetic field in the stator using an AC waveform for stator current (and induce currents in rotor components). Direct Current machines mechanically induce an alternating field in the rotor by rotating the conductors through a fixed magnetic field.
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It uses a permanent magnet which is rotated by a crank. The spinning magnet is positioned so that its north and south poles passed by a piece of iron wrapped with wire. It was discovered that the spinning magnet produced a pulse of current in the wire each time a pole passed the coil. Furthermore, the north and south poles of the magnet induce currents in opposite directions. By adding a commutator, it is possible to convert the alternating current to direct current.
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Generator generates electricity. It has a wire armeture mounted in an electic field. When the wire armeture is rotated, electric current is induced in the armeture du to change in magnetic flux.
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Well a one phase alternator produces an output that is sinusoidal (i spelt that wrong i think!). Basically if you were to plot a graph of the output voltage in relation to time, it would look like a normal wave (a sin curve). Now imagine if you had two of these waves, one starting just when the other one is at zero level? That's a two phase supply. A two phase alternator supplies an AC (alternating current) voltage at two different phases. Difficult to explain without diagrams though! but generally the reason for this is an increase in power availability for the same voltage.
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Ever think about a motor? It's just a coil of wire. Therefore, when you apply a voltage, you get a huge current. What stops it is counter voltage induced in the coil that opposes the supplied voltage. This only occurs when the motor starts turning. By limiting the initial current, it gives the motor a chance to spin up slowly and develop this counter force. Then as you apply more current, the motor comes up to full speed under smaller current spikes. This extends the life of the coil. Now if they would just do this with light bulbs.
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In order to know how 3-phases of voltage (separated by 120 degrees) are produced, one would have to know how a 3-phase generator works and know a bit about electromagnetic theory.\n\nIn nearly all power plants (except for some wind turbines), a 3-phase synchronous generator is used.  This type of generator has one or more wire coils attached to the shaft (the rotor) and a set of coils evenly spaced around the frame surrounding the shaft (this area is known as the stator).\n\nThe coils on the rotor are energized by a small DC source and become constant electromagnets with north/south poles determined by the direction in which the current flows.  The shaft is moved by a source of mechanical power.  Generally a steam turbine is used where the steam is heated from some source of energy like coal, natural gas, nuclear etc.\n\nSo as you can imagine, we have one or more electrogmagnets attached to a shaft being rotated by a turbine.  Remember that these rotating electromagnets are inside the evenly spaced windings on the stator.  Faraday's law states that a time-changing magnetic flux in a coil will produce a voltage in that coil.  Since the rotor electromagnets are constantly changing position relative to the stator coils, the magnetic flux seen by the stator coils is also constantly changing.  The wire coils on the stator frame are evenly spaced such that the induced voltage waveforms will be spaced 120 degrees apart.\n\nSo, we then have sinusoidal voltage waveforms produced on the stator coils such that they are 120 degrees apart.  These coils on the stator are then connected in either wye or delta configurations and carefully hooked up to the power grid.\n\nSo that is a somewhat simplified view of what is happening.  There are various other complications that I have not mentioned, but are not important in getting the general idea.  You might be able to find a nice 3-phase electric generator animation on howstuffworks.com or Wikipedia.
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high torque compared to single phase. For the same power output the size of three phase motor will be smaller and also it will be less costly.
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Neither of the other answers makes any sense.  \n\nFirst, induction motors or anything for that matter don't "consume" reactive power.  Reactive power is traded back and forth.\n\nSecond, yes, there is an average reactive power component when induction motors run.  This has to do with the fact that induction motors are "inductive" (go figure, huh?).  To produce the needed magnetic field in their airgap and to have high efficiency they have a very large coil that except for a small series resistance is basically and inductor.\n\nInductors of course are reactive.  THe only thing that keeps the motor from being only reactive power is that the shaft output power forces some real power input.  However, some "magnetizing current" is required to run in any case, and there will always be some reactive power except perhaps in very rare circumstances.
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1. Motor driven Van de Graaff Generator.\n\n2. High voltage multiplier - Jacob's Ladder.\n\n3. High voltage induction coil - Tesla Coil.\n\n4. Flyback Transformer.
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I am unaware of any 2-phase electrical systems.  \n \nTo get 3-phase power from a single phase (as in your home electrical) system you need to have a single phase motor run a 3-phase generator.
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Electricity generated by relative motion of a magnetic field and an electric charge.\nMaxwell's 2nd equation states that a magnetic field that varies at a given point induces an electric field that exerts a force on an electric charge.  This force moves the charge.  The free electrons in a conductor are such a charge, and are moved by the relative motion of the conductor and the magnetic field.  \nGenerators and transformers are common applications of this effect.  In a generator the magnetic field may be intrinsically constant (created by DC or a permanent magnet), or varying (created by AC).  The conductor is a coil or set of coils.  No mechanical relative motion of the field and conductor is needed if the field is intrinsically varying.  If such relative motion is needed, the coil can be rotated with the magnetic field held stationary or vice versa, so relative motion of the conductor and the magnetic field occur.  \nIn a transformer the current is always AC and no mechanical motion is needed.  The magnetic field is produced by an input coil (an electromagnet), which shares its core with the output coil for good magnetic field coupling.
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A generator is a machine that converts mechanical power to electrical power, by making a conductor cut across a magnetic field's lines of force.  This is done by moving either the conductor or the magnetic field.  Current flows in the conductor if its ends are connected to an electrical load thus producing electrical power.  Because an opposing magnetic field is created by the current in the conductor, it requires mechanical energy to maintain this motion.
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So I don't think I saw an answer that I liked.  Motors move.  And the way motors move is with changing magnetic fields (electric current is changing with respect to time).\n\nWith AC motors, you have a changing current.  So you need to have a coil carrying the current, put it in a circle, and presto, you have a moving north pole moving around in a circle.  All you need is to have a magnet attached to a spindle, and the magnet will move around to follow the moving magnetic field rotating around in a circle.\n\nWith DC current it's different you do not have a changing current, but instead you have a steady current.  So how do you get the magnetic field to change?  You put a special device in that will flip the polarity of the voltage every half turn (or quarter turn depending on what you want).  So what happens is you get current flowing one way, and the magnet on the spindle moves to line up with the magnetic field, then on the spindel you have brushes which make contact with the DC voltage, as the spindle moves, the voltage is cut off, and then is reapplied, but now the voltage is reversed, and the north pole of the magnetic field is on the other side.  So the spindle moves, and the voltage is cut off, and then put back on and again reversed.  The DC motor as it moves reverses the voltage every half or quarter turn (depending on how you want to make it) so the motor creates the time varying magnetic field itself.
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Brushless generators have a fixed magnetic field which rotates through the AC output windings.  As the engine speed or load varies the output voltage will change.\nGenerators which are not brushless are able to control the magnetic field.  This supplies the ability to introduce a feedback loop to control the output voltage.\nRead my generator FAQ.  It may better answer your question.\nhttp://members.rennlist.org/warren/genfaq.html
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Get a Small DC Motor with Two Wires, and an LED from Radio Shack, then, figure out a way to put a small fan blade on it, and put a small Electric Fan in front of it, blowing Air onto Your small Fan to turn the Motor to demonstrate how a Windmill could power a Generator, and produce Electricity.
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An spinning alternator produces alternating current. After each half cycle, the opposite side of the coil passes through the same magnetic field. As the coil passes through the magnetic field, current always flows in the same direction, but the coil keeps flipping, so the result is alternating current. \n\nIn the case of a car alternator, its intention is charge the battery, which requires direct current. The diode only allows current to flow in one direction, converting the AC into DC, which can be used to charge the battery. \n\nIf the diode goes open ciruit, then no current will flow at all. If the diode goes short circuit, it will allow AC to flow, which will not charge a battery and can cause damage.