Naked Science Forum

On the Lighter Side => New Theories => Topic started by: ionels on 22/01/2021 09:38:10

Title: Electromagnetism through a Steel Cable
Post by: ionels on 22/01/2021 09:38:10

Hello everybody. Let's imagine an electromagnet and instead of the usual core we have a steel cable. Let assume that the cable is stretched, it is long (~100 yards)  and the coil is placed at one end of the cable. The purpose is to transform the cable in a kind of a magnet along its entire length, just as long as the electromagnet works (~10 seconds).
I have two questions:
1. Is it possible to create big attraction forces on the cable?
2. If yes, is it the attraction force the same along the cable ?

Title: Re: Electromagnetism through a Steel Cable
Post by: Petrochemicals on 22/01/2021 15:14:53

Is the cable earthed

Title: Re: Electromagnetism through a Steel Cable
Post by: ionels on 22/01/2021 17:54:11

No, the cable is not earthed. Should be ?

Title: Re: Electromagnetism through a Steel Cable
Post by: Bored chemist on 22/01/2021 18:01:46

Quote from: Petrochemicals on 22/01/2021 15:14:53

Is the cable earthed

How was that ever going to make a difference?

Title: Re: Electromagnetism through a Steel Cable
Post by: Hayseed on 22/01/2021 21:02:31

"Is it possible to create big attraction forces on the cable?"

Yes

"If yes, is it the attraction force the same along the cable ?" 

No......with hanging cable.

No.......with grounded cable.   Grounding an object allows object to sink and source charge.

Yes.......if you loop the cable.

Title: Re: Electromagnetism through a Steel Cable
Post by: Kryptid on 22/01/2021 21:35:26

You'd basically have a very long electromagnetic, so it could indeed produce strong magnetic attraction (assuming sufficient current is applied).

Title: Re: Electromagnetism through a Steel Cable
Post by: evan_au on 22/01/2021 21:50:34

The alloys used in steel cable are optimized for strength, not for its magnetic properties.
- But I guess you could select a different alloy which had a reasonable compromise between these different goals...

One challenge is that a magnetic field declines as roughly 1/distance
- The steel cable will extend this ratio by a factor of perhaps 10-100 (depending on the permeability of the alloy), but the ends of the cable will be effectively unmagnetized.

Another challenge is "magnetic saturation": When the selected magnetic alloy is subjected to a magnetic field higher than the saturation level, it effectively "ignores" any higher magnetic field; you may as well have air in the core of the magnet.

So you will have a region in the core that is in magnetic saturation
- and a region slightly further away that is normally magnetized
- and a region even farther away that is effectively unmagnetized

Title: Re: Electromagnetism through a Steel Cable
Post by: Bored chemist on 22/01/2021 23:34:16

Quote from: Hayseed on 22/01/2021 21:02:31

No.......with grounded cable.   Grounding an object allows object to sink and source charge.

Does anyone care about charge?