How to wire a STRONG electromagnet

  • Context: Undergrad 
  • Thread starter Thread starter Undacuva
  • Start date Start date
  • Tags Tags
    Electromagnet Wire
Click For Summary

Discussion Overview

The discussion revolves around the construction and optimization of a strong electromagnet using a ferrite core. Participants explore various factors affecting the magnetic field strength, including winding methods, core material, current, and voltage. The conversation includes technical reasoning and suggestions for improvement.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested
  • Mathematical reasoning

Main Points Raised

  • One participant describes their setup with a ferrite core and multiple coils but expresses dissatisfaction with the magnetic field strength.
  • Another participant emphasizes the importance of factors such as current intensity, number of turns, core material permeability, and the intended strength of the electromagnet.
  • There is a suggestion that the type of ferrite used may not be suitable for the desired application, with a recommendation to consider using steel instead.
  • Participants question whether the strength of the electromagnet increased as expected with the addition of extra windings.
  • One participant notes that increasing voltage could be beneficial, but also warns about the dangers of high voltage requirements for significant strength increases.
  • Another participant indicates that to increase current, one could decrease resistance or increase voltage, referencing Ohm's Law.
  • Concerns are raised about the core material potentially having low permeability or being saturated if too many ampere-turns are applied.
  • There is discussion about the trade-off between voltage and current, suggesting that the optimal combination depends on the power supply available.

Areas of Agreement / Disagreement

Participants generally agree on the importance of current and core material but express differing views on the effectiveness of the winding method and the potential benefits of increasing voltage. The discussion remains unresolved regarding the best approach to achieve the desired magnetic strength.

Contextual Notes

Participants mention the variability in ferrite materials and their properties, which may affect the electromagnet's performance. There is also uncertainty regarding the optimal number of windings and the implications of using different core materials.

Undacuva
Messages
8
Reaction score
0
Hi everyone,
I have a 12mm long hard ferrite core that I want to use as an electromagnet. I have wound it with 0.8mm copper as tightly as I can by hand, in a single layer, but the field is not strong enough. I have placed another coil over that first coil, and then a third coil, each in parallel - branching before the core, and then re-connecting afterward - wound concentrically in the same direction, to increase the number of windings. I'm still not getting the magnetic force I need. The electrical source is a car battery with 490 cold cranking amps (CCA) -- There is no overheating now that I have 3 branches.

Am I doing something wrong? Is there a winding method that will work better? Do I need higher voltage or just higher current?
 
Physics news on Phys.org
http://easycalculation.com/engineering/electrical/solenoid-force.php
http://www.ehow.com/how_5969962_calculate-force-electromagnet.html
http://www.byronacademy.org/knowledge-center/view/calculatiing-emf-in-solenoid/
http://www.electronics-tutorials.ws/electromagnetism/electromagnets.html
http://en.wikipedia.org/wiki/Permeability_(electromagnetism )

The mains factors are:

- the intensity of the current in the wires
- the number of turns
- the length
- the permeability of the material
- and also what your objective is: why is the field "not strong enough", how do you expect?

You need to check all of them.
 
Last edited by a moderator:
Undacuva said:
Hi everyone,
I have a 12mm long hard ferrite core that I want to use as an electromagnet. I have wound it with 0.8mm copper as tightly as I can by hand, in a single layer, but the field is not strong enough. I have placed another coil over that first coil, and then a third coil, each in parallel - branching before the core, and then re-connecting afterward - wound concentrically in the same direction, to increase the number of windings. I'm still not getting the magnetic force I need. The electrical source is a car battery with 490 cold cranking amps (CCA) -- There is no overheating now that I have 3 branches.

Am I doing something wrong? Is there a winding method that will work better? Do I need higher voltage or just higher current?

There is a huge range of 'Ferrite' materials so you would need to specify what its permeability is. The original application it was used for would indicate what its permeability is likely to be. Basically, ferrets that are used for high frequency RF work have low permeability in order to have low loss in the material.
You may be better to use a piece of steel for your purpose - readily available in many shapes and sizes and easy to cut and shape.
 
It would be interesting to know if the "strength" increased as expected when you added the extra windings? eg did it double then treble?
 
Undacuva said:
Am I doing something wrong? Is there a winding method that will work better? Do I need higher voltage or just higher current?
It all depends on amps, turns, and core material. Swap your ferrite core for a steel bolt and see how that works out.

EDITED
You have your 3 layers electrically connected in parallel? For a stronger magnet, either add more layers still, or replace what you have with thicker wire that can carry more current from your battery. Just watch that it doesn't overheat, though.

Good luck with your experimenting.
 
Hi everyone,
Thanks for the responses. It seems that no-one has any issues with my winding method. What about increasing the voltage? Is there any use in that? Or could I sacrifice voltage for higher current?
 
What matters directly is the current. To increase the current, you can either decrease the resistance or increase the voltage (Ohm's Law).
 
but how much stronger do you want? I mean if it needs to be 10x stronger you are looking at needing 120V which would be dangerous.

Did it get _any_ stronger when you added extra windings?
 
Undacuva said:
Hi everyone,
Thanks for the responses. It seems that no-one has any issues with my winding method. What about increasing the voltage? Is there any use in that? Or could I sacrifice voltage for higher current?

Unless you attend to the core material, you may not get anywhere. The core could have a very low permeability or you could be saturating it if you increase Ampere-Turns ad infinitum.

The Volts - Current compromise is always relevant. I think it will depend upon the power supply you have as to what is the best combination.
 

Similar threads

Undergrad Why is my magnetic levitation experiment not working?
  • · Replies 22 ·
Replies
22
Views
4K
High School Insulated vs uninsulated wire in electromagnet
  • · Replies 3 ·
Replies
3
Views
11K
Graduate Current: the speed of charges vs the number of charges past a point
  • · Replies 37 ·
2
Replies
37
Views
4K
Heating of a conductor (1000 turn coil)
  • · Replies 19 ·
Replies
19
Views
2K
Undergrad A strong field from a wire placed in an exterior B
  • · Replies 5 ·
Replies
5
Views
1K
Undergrad Building a Linear Induction Motor | Tips & Tricks
  • · Replies 16 ·
Replies
16
Views
3K
Undergrad Calculating magnetic field for a micro solenoid
  • · Replies 1 ·
Replies
1
Views
3K
Undergrad Induced EMF in a half vs. whole ferrite toroid
  • · Replies 1 ·
Replies
1
Views
2K
Graduate Calculating Gauss of electromagnet
  • · Replies 3 ·
Replies
3
Views
14K
Graduate Magnetic powder in a solenoid - how would it react?
  • · Replies 1 ·
Replies
1
Views
2K