is there any difference between energy store in inductor and in magnetic field ?
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The energy is stored in the magnetic field of the coil. There are no other things to store in the coil. “The energy stored in an inductor” is the short form of saying “The energy stored in the magnetic field”.\n\nSimilarly, the energy stored in the condenser means, “The energy is stored in the electric field”.\n\nThe energy stored in a coil can be calculated using, inductance and current. It can also be calculated independently using magnetic flux and volume of the coil. Both are one and the same energy.
994725
An electromagnet is an iron core with wire wrapped around it so that the magnetic field that forms at a right angle to the direction of current becomes intensified in a specific location.  The reason for using insulated wire in an electromagnetic device is that it is not the current (electron frequency) moving through the wire that the engineer is interested in, but the automatic magnetic field that forms outside the wire.  This field is able to be formed, collapsed and reversed whenever one wishes to do so.\n\nA gravitational field (as our planet for example) is always one directional and the direction of energy flow is toward the core point of our planet.  Below the Moho line mass has its gravitational waves all focused toward the core point.  This means that all gravitational waves below that line pass through the very center of our planet and attract all mass directly on the opposite side, and at the same time also attracts all the heat energy of our planet to the core point.  If this were not true, then our planet would have (nearly) the same temperature throughout.
1514
you must use insulated wire or you will effectivly just short out your power source.  most modern electro-magnets use wire that is insulated with a thin coating of a special varnish.  this allows more winding in a given space.  varnish insulated wire is available from nearly any electronics store or catalog or from any business that rewinds electric motors
138814
A computer Hard idsk is hardware device used to store the data.\nIt works magnetically and retains data even after power is removed.
288352
The induction motor sets up a rotating magnetic field due to the phase lag batween the phases. This magnetic field "chases"  the rotor and tries to get it to rotate at the same speed. Ideally, if the motor is \n1. not loaded, and there are no losses due to \n2. friction, \n3. eddy currents, \n4. induction and \n5. resistance losses, \nthe rotor *will* catch up with the magnetic field and would rotate at the synchronous speed. \n\nHowever the world we live in is not ideal. All the losses mentioned above gets the rotor to always fall slightly behind the speed of the magnetic field. The difference is called Slip.\n\nNow if you load the motor, the rotor falls more behind the synchronous speed, kind of like the load is slowing it down. Larger the load, larger the slip. \n\nAnother way to look at this: If you study the speed torque characteristics of an induction motor, the torque at synchronous speed is 0. So if a rotor manages to catch up with synchronous speed, there is no more torque acting on the rotor, so it slows down again ever so slightly (due to various losses). as soon as it slows down the torque kicks in again and pushes it towards sync speed. the end result is that the rotor always is "almost at" sync speed. most motor designs have max torque at about 90% sync speed.
280023
Short answer: The electromagnet is not doing work; if the motor is not stalled, it is doing work.\nSaturation occurs at some field intensity per unit core area. The bigger the core the more energy in the saturation field. Field energy is a function of current times number of turns in the coil. So in an electromagnet with a large core, more ampere-turns are used to make a higher-energy field. Theoretically it should take no electric power to maintain an electromagnetic field, because no mechanical work is being done. In fact superconducting electromagnets use exactly zero power. \nTo be using 90 watts, a small motor must be either doing mechanical work or stalled. The small armature core can sustain only a much less energetic field than the electromagnet. A magnetic field does work when it moves something against an opposing force. This energy loss reduces the field energy, and it takes electrical energy to restore the field.\nWhen the motor is stalled by too high a load, things work differently. No work is done and the winding may draw a lot of current and overheat. This is because the armature is designed for efficiency at speed but not stalled. It has a low-inductance winding (one with fewer turns and higher current) which can reverse polarity more easily, and two reversals are needed each revolution. Under no load, the armature runs at high speed and generates a "back-EMF" that results in almost no current drawn.
104827
An electromagnet , it is temporary magnet.without the electrocity, it is not a magnet.
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You are misunderstanding what energy actually is.\n\nA permanent magnet has no energy as such. It just exerts a force. The works is actually done moveing the object against the force. This means if an object was far away, it already had that "potential" energy with respect to the magnet. It loses this being pulled in. It regains it if you pull it away, and you supply that energy.
916842
I have a small wind turbine which uses permanent magnets instead of a field coil.  The main benefit I can see is in keeping the electronics on the ground.  As the wind speed increases, the output voltage (and power) from the generator will increase as well.  I have a shunt regulator at the batteries to prevent overcharging.  Everything outside on the tower is very simple and less likely to break.  Other than mechanical breakdown, repairs to the system can usually be made on the ground level.\n\nOn a gasoline powered generator, sometimes permanent magnets are turned inside the AC output coils.  This eliminates the need for brushes and the voltage regulator board.  AC output coils have been designed to supply 120VAC at 3600RPM.  If the engine speed changes, the output voltage will change as well.  Output voltage will also change with load variations.\n\nI have more generator information online.\nhttp://members.rennlist.org/warren/genfaq.html\nhttp://members.rennlist.org/warren/generator.html
743760
1.a) receives the alternating current. \n b) the magnetic properties are altered by the electromagnetic field. . \nc) by the alterations in the core induces other alternating current in this coil. \n2.a) because the alternating current induces the varying magnetic field.\nb) that magnetic flux is passed by the core to the secondary coil.\nc) yes an alternating one. \n\nBecause radioactivity destroy organic tissues.
52883
A moving charged particle will create a magnetic field.  Conversely, a moving magentic field can make an electric current.  The orientation of the magnetic field goes around the current.  So if you coil a copper wire and run a current through it, all of the magnetic field will add together in the middle of the coil and make a magnetic field.  You can wrap a wire around a steel rod, and make an electromagnet in this way.  But in electronics, what they can do is put two coils in close proximity.  As you run current through one coil, it creates a magnetic field.  The creation of the new magnetic field in the vicinity of the other coil will induce a current in that second coil.  This is called and inductor, and that's how induction works.
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Energy is defined as the ability to do work.  It is a measurment of how much you would be able to move an object through a specific distance.  It is measured in Joules.\n\nThere are various means of calculating the amount of energy stored in things.  For electromagnetic waves it gets a little complicated.  But suffice it to say that electromagnetic waves have energy stored in them.  You can do work with an electromagnetic field by seeing it's effect on a magnetic.  The bar of magnet moves, so energy is being expended....\n\nMass is defined as a measurement of how much matter an object contains.  It is measured in kilograms.\n\nWaves really are just a transmission of energy.  Sound wave, you move air particles and the energy travels through the air.  Electromagnetic Waves, you move a magnetic, and current is induced in a wire, or waves propagate through the air (movement transfered to EM waves).
544765
The difference is that the pipe allows for complete current loops around the circumference of the pipe, which will generate a magnetic field in opposition to the falling magnet.  In a coil, with the ends disconnected, you won't have this happening.  You induce some emf in the coil, but it's not a closed circuit, or at least not one that can generate a magnetic field opposing the falling magnet.  You could consider small current loops induced within the wire, or around the circumference of the wire, depending on the magnet's orientation, but these will be small and weak compared to a current loop all the way around a pipe.  However, if you wire one end of the coil to the other,  you should get some Lenz's law braking of the magnet.   \n\nIt's a very clever idea for a demonstration.  I had to go set it up and test it myself with some magnet wire wound around a glass tube and a glass tube sheathed in a copper pipe, to see the effect you described.  Like I said, if you connect the coil to itself, you will see some effect, but it's not nearly as strong as the copper tube.  I think this is because the emf is induced in the coil as a whole, and not as a local loop as in the pipe, so you have a field of the same total strength, but it's not as strong locally. I think I'm going to have to play around with this some more and maybe do some actual math to figure out the full details.
930867
Capacitors = stored energy, leaking dieletric (if hazardous), and/or reverse polarity may cause rupture/failure. Over-voltage can cause failure also. Always store de-energized and shorted.\n\nInductors = No hazard if de-energized. Inductors in service with an over-current condition can overheat and cause burns or failure of the component.
1182896
Voltage applied to the primary coil of a transfer causes an electrical current to begin to flow, and that causes a magnetic field to form.  As the voltage drops back to zero and reverses, the field collapses and then forms in the opposite direction.  This changing magnetic field induces a voltage in the secondary coil.  If that coil is connected to some load, the voltage causes current to flow.\n\nIf the ferromagnetic core which concentrates and contains the magnetic field is laminated, and there is some room for these laminations to move, they move in response to the changing magnetic field.  If there is no movable magnetic material in the field, you hear nothing.\n\nIt need not be harmonic.  It depends only on how the magnetic material is affected by the force applied to it by the magnetic field, and that field depends on the variation of the applied voltage with time.  It need not be the sinusoidal pattern at 50/60 Hz of commercial power mains.  In a switching power supply, it's a square wave.
1137859
Large commercial generators do not have permanent magnets. The rotating field is magnetized via slip rings that feed current into it's windings. The current is generated by the exciter which is either a small generator attached to the end of the shaft or, in modern applications, an electronic SCR converter.
1055209
The top answer is incorrect.  In both cases, the current woul go on infiniitely, because energy will keep on traveling, but the current will get weaker and weaker, because it will keep spreading aparty, until the ammount of current in negligeble.\n\nHope this helps.