# What is Electromagnetic coil: Definition and 17 Discussions

An electromagnetic coil is an electrical conductor such as a wire in the shape of a coil, spiral or helix. Electromagnetic coils are used in electrical engineering, in applications where electric currents interact with magnetic fields, in devices such as electric motors, generators, inductors, electromagnets, transformers, and sensor coils. Either an electric current is passed through the wire of the coil to generate a magnetic field, or conversely, an external time-varying magnetic field through the interior of the coil generates an EMF (voltage) in the conductor.
A current through any conductor creates a circular magnetic field around the conductor due to Ampere's law. The advantage of using the coil shape is that it increases the strength of the magnetic field produced by a given current. The magnetic fields generated by the separate turns of wire all pass through the center of the coil and add (superpose) to produce a strong field there. The more turns of wire, the stronger the field produced. Conversely, a changing external magnetic flux induces a voltage in a conductor such as a wire, due to Faraday's law of induction. The induced voltage can be increased by winding the wire into a coil because the field lines intersect the circuit multiple times.The direction of the magnetic field produced by a coil can be determined by the right hand grip rule. If the fingers of the right hand are wrapped around the magnetic core of a coil in the direction of conventional current through the wire, the thumb will point in the direction the magnetic field lines pass through the coil. The end of a magnetic core from which the field lines emerge is defined to be the North pole.
There are many different types of coils used in electric and electronic equipment.

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1. ### B Understanding magnetic flux change during the falling of magnet

If I drop the magnet into the electromagnetic coil, is magnetic flux density changed or cross sectional area changed during its falling? Actually I dropped a neodymium magnet into the coil and there was the voltage induced but I don't know what's the factor that induce the EMF in this case. Also...
2. ### Electronics Would This Setup for a Ball Bearing Accelerator Work?

I need a method to accelerate a ball bearing down a pair of wire tracks, and to generate a consistent amount of force on every activation. Please critique my tentative design: I want to use an inductive coil activated by a proximity sensor to generate a transient EM field to accelerate the ball...
3. ### Amplify ferrite core solenoid electromagnetic range

Hello all, I'm playing around with a PIC + LCC Tank to send - at a 5MHz frecuency - some numeric data via BPSK. The receiver is a loop antenna placed in the ground. The sender antena (L) is a ferrite core solenoid (N=10). As having a larger core, or increasing the Number of coils around the...
4. ### A Coil excitation adjustment on 3D Ansys Maxwell transient analysis

Hi. I am making a 3D Ansys Maxwell project to design DC electromagnet. My model as in attached pictures. I have couple of questions. 1- How important the width value of sheet of coil terminal? Altough I did not change number of conductors and current of coil, changing the width of sheet of the...
5. ### Is the magnetic flux density B constant?

Summary:: Is the magnetic flux density B constant? Is the magnetic flux constant? I am working on a project design for Uni and I am stuck. In a magnetic circuit is either the magnetic flux or the magnetic flux density B constant? This magnetic circuit has all different cross section areas and...
6. ### Electromagnetic coil and capacitors vs resistance

I'm not really sure if this is even scientific but while calculating how much energy is stored in electromagnetic coils and capacitors, pretty much the same formula is used: For electromagnetic coils it's U=0.5LI2 For capacitors it's U=0.5CV2 Why I think they're the same is that in a sense L to...
7. ### Electromagnet Design for Separating Ferrous Material from an Ore Mixture

Good day I've been the task of designing an electromagnet to remove ferrous material from ore mixture. I've calculated the flux density require to remove the particle from underneath a burden depth of 400mm; which is 792.7177 Gauss. (Force index is: 1.5710*10^6 G^2/m) However what I've been...
8. ### The Peculiar Behavior of a large electromagnetic coil

I have these two very large (ferrous core) coils, They are basically identical, each 200mm long and have a diameter of 100mm. The core is medium grade steel One coil is receiving an input of 8V(peak-to-peak) @ 4 MHz from the function generator. The second coil is placed 1m away, and is...
9. ### B Non-ferrous solenoid actuator -- Force calculation

I'm trying to come up with a lightweight solenoid linear actuator, by constructing two electromagnets that telescope. The outer coil would be wrapped around a soda straw, and the inner coil would fit inside the soda straw and be wrapped around something smaller, like a bamboo skewer (which also...
10. ### Bar magnet wrapped in electromagnetic coil

If I wrap a coil around a bar magnet and shoot current through the coil so that the magnetic field of the electromagnet is at the same polarity of the bar magnet will I have amplified the magnetic field of the bar magnet maintaining the same magnetic shape but bigger/stronger?
11. ### Electromagnetic Coil 2 SS Rods Converging

Howdy all, I'm looking at having two (preferably) stainless steel rods inside a plastic tube (for insulation and so they don't touch) with a push spring inside and between the two rods pushing each other away from one another, when not activated inside of an electromagnetic coil. When the coil...
12. ### Modeling and Measuring an Electromagnetic Coil in ANSYS HFSS

I've been attempting to model a simple electromagnetic coil using HFSS, and have so far been unsuccessful. I have no problems constructing the coil; this is a simple geometry problem. I have a wire of a known geometry with insulation surrounding the wire, then a construct a helical path and then...
13. ### Electromagnetic Coil Strength from Moving Liquids?

I was reading about drift velocity and according to http://amasci.com/miscon/speed.html 100VDC at 1A moving through ~12 AWG wire would produce an electron velocity of 8.4 cm/hr. Since that is incredibly slow I'm curious if a charged fluid (something like the oil used in an oil-based van de...
14. ### Current in an Electromagnetic Coil

What keeps the current in an electromagnetic coil from moving between the touching conductors and instead go through the conductor? Is it the resistance being much higher between two touching sections of the coil? Is there a small amount of current "leaking" between each loop where they touch?
15. ### Force of neodymium magnet inside an electromagnetic coil

Hey guys, Im trying to design a electric gear shiftier for a motor bike. Basically I require about 200N of force to change gear with a 10mm throw (in both directions). I would like to use a tube neodymium magnet. (23mm diameter 25mm high with a 5mm hole throw the centre with a N48 grade) What I...
16. ### Force of neodymium magnet inside a electromagnetic coil

Hey guys, Im trying to design a electric gear shiftier for a motor bike. Basically I require about 200N of force to change gear with a 10mm throw (in both directions). I would like to use a tube neodymium magnet. (23mm diameter 25mm high with a 5mm hole throw the centre with a N48 grade) What...
17. ### Calculating Current Draw in Electromagnetic Coil

My situation is this. I have 6,560 ft (4 lb) of polyurethane-nylon coated #27 gauge round wire wound in a coil with an air core of 1 1/8 in. wide x 4 in. long x 4 in deep. I don't want to destroy my precious electromagnet so I'm afraid to give it some current. What would happen if I attached a...