how can I have a plate that magnetically attracts a beam

[johnnyBronny]

Dear all,

I am a new member in this forum. I am working as a research engineer in a company, and I am currently engaged in a very important research project. As I am a mechanical engineer, I don't understand much of electromagnetism. My question is: I want to have a plate that magnetically attracts a beam, i.e., creates an attractive force between the plate and the beam. I know I need two poles. What can I do to have the beam attracted? One pole on the magnet, and other on the beam? Or how? I want the attraction to be made in only one direction but in the two ways. How can I do this? Do I need two magnets, oriented 180 degrees in relation to each other? or how would you do that? Sorry about not telling more information, but as you can understand the engineering companies work with non-disclosure agreements.


Thanks a lot,
Johnny

 

[Skogsgurra]

A light beam? Or an electron beam? Or, perhaps, an iron/steel beam? Or any other beam?

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[johnnyBronny]

Hi,

Thanks for the reply,

It is a steel beam.

regards,
Johnny

 

[Skogsgurra]

The most common configuration is a U-shaped core with windings on it. You will then get a force that is proportional to current squared. Squaring removes the sign so you canot push - only pull.

If you also need to push, you need a to bias the whole thing with a "DC" field in the beam.

Too many unknown to be able to say anything at all. Dimensions? Distances? Forces? Response time needed? Those are just the beginning. Then, there are costs and other things.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[johnnyBronny]

Hi Skogsgurra,

Many thanks for the reply,

I did not understand what are windings.

Dimensions are between 0.2 m (smallest) to 2 m (largest).Distances are between 0.02-0.1 m, Response time needed shall be very short, the shortest possible, I would say. Forces shall be in the magnitude of 1000-1500 N

Can you give me a reference of a book where this is explained? I would like to learn more about it.


Many thanks again,
Regards,
Johnny

 

[Skogsgurra]

Winding(s) are needed to control the magnetic flux. You can, of course, also use a permanent magnet. But then you need to control flux in some other way.

Any text-book on electric and magnetic phenomena will tell you what you need to know. But you needn't buy a book - the following article is all you need to read:

http://en.wikipedia.org/wiki/Magnetic_field

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[johnnyBronny]

Skogsgurra,

Can you please tell me how can I magnetize a beam with a magnet in form of a plate or something else? The magnet has 2 poles,one positive and one negative,right? And the beam? How can the attraction occur? I don't get even after reading the article in the wikipedia. Can you explain more in detail what do I need to do? I already have the shape of the beam, and I think stuff can be put on the top but without a change on the existing shape.



thanks,
Johnny

 

[Skogsgurra]

That Wiki article contains all you need to know to get started. I'm afraid that I cannot inform you any better.

Magnet forcees are non-linear and working across distances like 20 to 100 mm is not trivial at all. Especially not at force levels equivalent to the weight of a heavy (very heavy) person.

Why do you need the whole thing to work on magnetic principles? Is that absolutely necessary? There may be other solutions to the

There are design firms and consulting engineers that can help you.

Gunnar Englund

http://www.gke.org

--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

 

[logbook]

That wiki article was far too complicated.

Try this video instead electromagnet video

The forces you are talking about are massive. If you look for electromagnets used for lifting cars in scrap yards you will see how big they can get.

>I want the attraction to be made in only one direction but in the two ways.
This makes no sense. Try re-writing it using more sentences, or better still upload a sketch.

You probably cannot achieve what you want using permanent magnets. What will happen is that you get a lifting force of 100kg at distance, but as the poles snap together the force to separate them will be at least ten times greater! (Yes I know kg is a unit of mass not force; call it kgF if you like. A kg is more real to me than 9.8N).