Magnetic forces within a closed ferrous core

In summary, the conversation discusses the potential for a toroidal ferrous core, with windings and a DC current, to experience a "shrinking force". Upon further analysis, it is determined that the magnetic energy density should result in no force, but there could be a decrease in magnetic path due to the magnetization of the wedge-shaped material inside the coil. This reduction is independent of the current direction.
  • #1
Dorian Black
12
0
If a toroidal ferrous core has a number of windings round it and a DC current going through them, would this magnetic core be subjected to a 'shrinking force'? To phrase it more clearly, if the toroidal core was compressible, would it actually get compressed?

On the one hand, since the magnetic field (and hence magnetic energy density) is equal everywhere inside the core, it seems there should be no force. But then if you take a certain volume within the core, calculate the magnetic energy associated with it, then differentiate it with respect to any dimension, it wouldn't yield a zero. So what is exactly happening inside the core?
 
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  • #2
Analyse one turn of the coil with the circle of slightly wedge shaped magnetic material inside. That wedge will be magnetised with North and South magnetic poles. All these wedges will attract and so slightly reduce the magnetic path. That is independent of the current direction in the coil.
https://en.wikipedia.org/wiki/Magnetostriction#Explanation
 

Related to Magnetic forces within a closed ferrous core

1. What is a closed ferrous core?

A closed ferrous core is a type of magnetic core that is made up of a ferromagnetic material, such as iron or nickel, and has a closed-loop shape. This means that the core forms a continuous path for the magnetic flux to flow through.

2. How do magnetic forces work within a closed ferrous core?

Magnetic forces within a closed ferrous core are generated by the interaction between the magnetic field produced by an electric current passing through a coil of wire and the magnetic properties of the ferrous material in the core. This creates a concentrated magnetic field within the core, which can be used for various applications such as transformers and electromagnets.

3. What factors affect the strength of magnetic forces within a closed ferrous core?

The strength of magnetic forces within a closed ferrous core is affected by several factors, including the material and shape of the core, the amount of electric current passing through the coil, and the number of turns in the coil. Additionally, the properties of the ferrous material, such as its permeability and saturation point, also play a role in determining the strength of the magnetic forces.

4. Can magnetic forces within a closed ferrous core be controlled?

Yes, the strength of magnetic forces within a closed ferrous core can be controlled by adjusting the amount of electric current passing through the coil or by using different types of ferrous materials with varying magnetic properties. Additionally, the shape and size of the core can also be modified to alter the strength of the magnetic forces.

5. What are some practical applications of magnetic forces within a closed ferrous core?

The use of closed ferrous cores is common in a variety of electrical and electronic devices, such as transformers, inductors, motors, and generators. They are also used in magnetic shielding to protect sensitive equipment from external magnetic fields. Additionally, closed ferrous cores are essential in communication systems, where they are used in antennas and filters to manipulate and transmit electromagnetic waves.

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