What is an Electromagnet | How Electromagnet Works


What is an Electromagnet?

An electromagnet is actually an iron core covered with wire that is connected to a power source. You can find out why this iron core becomes magnetic again with a little experiment.

The electromagnet was invented by William Sturgeon in 1826, with the electromagnetic effect already being demonstrated in 1820 by the Danish physicist Christian oersted.


How Electromagnet Works

The deciding factor for the way this works is Hans Christian First’s discovery that an electric conductor creates a magnetic field. This magnetic field gets stronger as you move the wire around the coil.

To obtain a perfect electromagnet, the conductor is wrapped around an iron core. (Origin Of The Magnetic Field  ) There is also the option of wrapping the conductor around multiple iron cores or horseshoe-shaped cores. This increases the magnetic power of the magnet. 

The number of wire windings and the strength of the current also affect the attraction of the magnet.  The magnetic field flows in one direction and depends on the technical direction of the current.  The direction of the field lines of a magnet can be determined by the corkscrew rule. 

What is an Electromagnet,  How Electromagnet Works

Origin Of The Magnetic Field  

If an electric voltage is applied to a coil, an electric current flows through it depending on the voltage level and the electrical resistance. 

This current generates a magnetic field in the coil, shown by the red field lines in the figure. The coil is usually made of enamel-insulated copper wire, as copper has very good electrical conductivity. In the case of extremely large coils, aluminum is also used as a conductor material in special cases to reduce weight or cost.


Amplification and Conduction of Magnetic Field 

The propagation of a magnetic field depends greatly on the material and its size through which the magnetic field flows. 

Air has a comparatively high resistance to magnetic fields, whereas iron materials such as steel have high magnetic conductivity and conduct magnetic fields very well. 

For this reason, the coil’s magnetic field is directed into the steel components. In simple words it is also said that the magnetic field is stronger than the steel components. Correctly, however, there is no amplification; Rather, the magnetic field weakens only to a very small extent due to the good magnetic conductivity of the ferrous material.

What is an Electromagnet,  How Electromagnet Works

The simplest form of electromagnet is the holding magnet, which also has a magnet holding the magnet. The magnetic circuit consists of a vessel-shaped magnetic body with an internal pole that surrounds the coil on 3 sides.

With this device the force that can be applied to a magnetic component is greatly reduced as the component moves away from the so-called pole face. 

If the electromagnet is to function as a linear actuator or lifting magnet, the highest potential forces with the largest possible stroke are generally needed. For this purpose, a movable iron part (armature) is arranged within the coil at some distance (air gap) from the stationary core. 

If current is supplied to the coil, the armature moves towards the core and strokes along the size of the air gap. For example the motion of the armature can be directed out of the electromagnet through an armature rod through a hole in the core. 


(What is an Electromagnet | How Electromagnet Works)


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