What is Electromagnet: Definition and 371 Discussions

An electromagnet is a type of magnet in which the magnetic field is produced by an electric current. Electromagnets usually consist of wire wound into a coil. A current through the wire creates a magnetic field which is concentrated in the hole, denoting the center of the coil. The magnetic field disappears when the current is turned off. The wire turns are often wound around a magnetic core made from a ferromagnetic or ferrimagnetic material such as iron; the magnetic core concentrates the magnetic flux and makes a more powerful magnet.
The main advantage of an electromagnet over a permanent magnet is that the magnetic field can be quickly changed by controlling the amount of electric current in the winding. However, unlike a permanent magnet that needs no power, an electromagnet requires a continuous supply of current to maintain the magnetic field.
Electromagnets are widely used as components of other electrical devices, such as motors, generators, electromechanical solenoids, relays, loudspeakers, hard disks, MRI machines, scientific instruments, and magnetic separation equipment. Electromagnets are also employed in industry for picking up and moving heavy iron objects such as scrap iron and steel.

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  1. N

    What units are used in the expression P = (B^2 A)/(2 mu_o)?

    HI EVEYONE, NEED TO TAALK TO SOMEONE WHO IS UP ON CALCULATING THE VALUE OF (B), REQUIRED TO LIFT A PLATE OF XXNEWTONS. ALSO ESTIMATE THE M.M.F REQUIREDTO LIFT THE SAME PLATE. ANY TAKERS PLEASE? THANKS
  2. I

    Circuit diagram symbol for an electromagnet

    Is there a circuit diagram symbol for an electromagnet? Am I correct in thinking that it is a line with a coil going round it? I have looked all over the web, and cannot find confirmation of this. Thanks, Iceman123
  3. H

    How can I determine the strength of an electromagnet with an iron core?

    lately i have been really interested in electromagnets. i have been building small ones and i will eventually (at least i want to anyway) build a strong electromagnet (not some toy). from what i understand you can increase the strength of an electromagnet by adding more current, turning the wire...
  4. S

    Electromagnet & Spring: Attraction & Compression?

    If we take an electromagnet and then place it at one end of a metal spring, the spring will get attracted to the magnet. Now if at the other end of the spring, a metal bar is placed, the metal bar will get attracted to the spring. My question is that will the spring get compressed...
  5. B

    Electromagnet homework problem

    I am stuck on this homework question and would apprieciate a bit of help please. Put the following sentences in the correct order to explain how the bell works. *The springy metal pulls back the hammer *A current flows through the electromagnet *At the same time, the circuit is...
  6. J

    Creating a Smooth Radial Electromagnet: Tips and Tricks

    Hello, Does anyone here know how to make a radial electromagnet? I'm trying to figutr out how I would wind the coils. I want to make a doughnut magnet with a single north pole on the inside diameter and a south pole on the outside diameter. It will be critical that the field on the inside...
  7. J

    Choose the Best Core Material for Your Electromagnet

    Hello all, I'm working on building a resonating electromagnet and I was curious to know what the best core material would be. I know soft iron is a good common one and I've also heard of using ferrite. A third thing I was thinking about was using a magnet as the core but I was cursious to know...
  8. C

    How to build a Large electromagnet?

    I need to build an electromagnet. I have 2500 feet of 19 gauge magnet wire, and an iron core available. I'm not sure how to get a power supply that would supply enough amps to make the magnet strong enough... Anyone have any suggestions? Caleb
  9. C

    Calculate Magnetic Field of Electromagnet with Hollow-Iron Core

    Hey everyone, I'm doing a physics project, and I need to construct an electromagnet with a hollow iron core. I have searched everywhere on google, and checked my physics textbook as well, but have unfortunately found nothing. I basically just need the formula of how to calculate the magnetic...
  10. M

    Help making an Electromagnet

    I am working on a physics project, and I need to build a strong electro magnet. I have previously made many real weak ones simply by coiling wire around a nail and conecting it to a AA battery(1.5V). Can anyone help me make a stronger version. I tried using a powersupply from an old computer, it...
  11. T

    Calculating Load of an Electromagnet

    Can anyone tell me how to i can calculate the amount of load an electromagnet will pull. the electro magnet has 3 poles. 1 pole is the centre core of the magnet (N) there are two adjacent poles which are on either side of the coil which are joined across the other (s) end of the core. If i...
  12. M

    What is the Formula for Determining the Strength of an Electromagnet?

    I think I remember there being a formula to determine the Strength of an Electromagnet, but I just can't remember what it is, and i can't find it any where. of course the strength will depend on many things, # of coils, current, voltage?, Power? distance away from magnet and other things.
  13. H

    Electromagnet Equasion Help PLEASE

    Electromagnet Equation Help PLEASE! I have found many equations on modeling electromagnetic forces but being a high-school student, they don't make any sense to me. what i need is this: i need someone to tell me how i can find out Xgauge wire + Ywraps around Zdiameter(feet) steel core +...
  14. F

    Can Electromagnets Pull Out Car Dents?

    I was wondering if it is possible to pull a hail-size dent out of a car with an electromagnet. I have seen an electromagnet that is 1-3/4" diameter and can hold 700 lbs. Will this do anything or what?
  15. C

    Simulation of Electromagnet Force

    Hello, This sounds like a silly idea, but I am trying to simulate all forces of in the universe on my computer, putting in the correct physics equations for each force, one by one. I was already able to simulate the force of gravity with the following formulas/equations: G = 6.674205043E-11...
  16. L

    A magnetron's electromagnet

    I'm in the process of refurbishing a 915mhz 30kw Microwave power supply. The problem I'm having is that the electromagnet coil's water tubing is busted, and so we are having to replace it, and the standard replacement part is somewhat expensive ($2000+) and will take weeks to arrive. I've...
  17. J

    Electromagnet pulse coil powered by static charge

    Hello, I have a question concerning electromagnet coils and static electricity. If one were to generate a static charge and store it up some how (like in a Leyden jar or something), and that charge was then dumped over a small electromagnet, would there be enough energy to provide a small...
  18. billtodd

    Electromagnet, tesla equations

    I know that an electro magnet can have a higher tesla rating when you increase the current or the times revolved around the core but I was wondering if someone could give me an equation or set of equations involving the length of wire, gauge of wire, current, cross sectional area of the wire...
  19. W

    High frequency electromagnet

    Is it possible to make very small, low power, but high frequency electromagnets and stack them up or inside each other to make a high field strength, high frequency magnet? or does the presece of other magnetic fields cause the same problems you would expect with only one coil?
  20. F

    Inductor is pretty much and electromagnet

    Few real basic questions about inductors/inductance: As I understand it an inductor is pretty much and electromagnet (coil of wire around a ferromagnetic material). Am I right? I know inductors resist changes in current. The more inductance a circuit has the greater it resists AC. Does...
  21. J

    Electromagnets: What Makes Them Stronger?

    -Why must you use an iron core to make an electro magnet? Why can you use things like plastic or aluminum? -Why must you wind the wire in the same direction around the iron core to make make the electromagnet. -What happened if some of the wire is wound in one direction and some of the...
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