N00b question about learning about magnetism

[THX-1138]

I'll probably get slapped around for this, but I'm looking for moderately dumbed-down texts about magnetism.  The sort of 'whats' and 'hows' I want to know include things like

• What [common] materials make the best electromagnets?  (I.e., most powerful when energised. least retained magnetism when de-energised.)
• What are the best materials for an air-cored electromagnet closed at both ends (such as for an oscillating actuator)?
• If I use electromagnets along an air-core channel, what should the spacing be?  The strength?  What do the field rise and fall curves look like (so the next can be energised with minimal loss to the falling field of the previous one.  Where in the travel of the magnetic core should one trip on, or off?
• What sort of material would one use for the slug in an air-cored actuator?  Iron?  Steel?  Ferrite?  A neodymium magnet?

All those, and then I'd like to understand the 'why' (or 'why not') aspects of each.  But I don't know the terminology to ask for what I don't know.

Links to references sources would be great?

Thanks!

[StringJunky]

57 minutes ago, THX-1138 said:

I'll probably get slapped around for this, but I'm looking for moderately dumbed-down texts about magnetism.  The sort of 'whats' and 'hows' I want to know include things like

• What [common] materials make the best electromagnets?  (I.e., most powerful when energised. least retained magnetism when de-energised.)
• What are the best materials for an air-cored electromagnet closed at both ends (such as for an oscillating actuator)?
• If I use electromagnets along an air-core channel, what should the spacing be?  The strength?  What do the field rise and fall curves look like (so the next can be energised with minimal loss to the falling field of the previous one.  Where in the travel of the magnetic core should one trip on, or off?
• What sort of material would one use for the slug in an air-cored actuator?  Iron?  Steel?  Ferrite?  A neodymium magnet?

All those, and then I'd like to understand the 'why' (or 'why not') aspects of each.  But I don't know the terminology to ask for what I don't know.

Links to references sources would be great?

Thanks!

You're asking for too much. You need to sit down and start learning magnetism from scratch

[studiot]

1 hour ago, THX-1138 said:

I'll probably get slapped around for this, but I'm looking for moderately dumbed-down texts about magnetism.  The sort of 'whats' and 'hows' I want to know include things like

• 1) What [common] materials make the best electromagnets?  (I.e., most powerful when energised. least retained magnetism when de-energised.)
• 2) What are the best materials for an air-cored electromagnet closed at both ends (such as for an oscillating actuator)?
• 3) If I use electromagnets along an air-core channel, what should the spacing be?  The strength?  What do the field rise and fall curves look like (so the next can be energised with minimal loss to the falling field of the previous one.  Where in the travel of the magnetic core should one trip on, or off?
• 4) What sort of material would one use for the slug in an air-cored actuator?  Iron?  Steel?  Ferrite?  A neodymium magnet?

All those, and then I'd like to understand the 'why' (or 'why not') aspects of each.  But I don't know the terminology to ask for what I don't know.

Links to references sources would be great?

Thanks!

 

Asking questions like this is a good way to start.

I have added some numbering to help refer to them.

 

First and foremost you need to know that electromagnets are magnetic because of the electric current and not because of any material.
The larger the current the stronger the magnetic field. (This is not all but it is a start).

Therefore to answer

(1) the best material would be to make the wires from the best conductors of electricity, silver or gold or copper.

(2) The material (air) is already defined in an air cored device.

(3) I don't follow what you are trying to do here, it sound complicated enough to come back to when you have got hold of some more basics.

(4) The purpose of any core is to concentrate the magnetic field withing the electromagentic windings. Without a core (air cored) the field would spread out widely beyond the windings and that part would be useless/lost. Further certain materials - soft iron , (not steel) have a high what is known as susceptibility which allows the core material to boost or reinforce the electromagnetically generated field.

 

Let us know how you get on with these comments so we can make more progress.

[THX-1138]

On 11/6/2018 at 1:49 PM, THX-1138 said:

I'll probably get slapped around for this, but I'm looking for moderately dumbed-down texts about magnetism.  The sort of 'whats' and 'hows' I want to know include things like

1. What [common] materials make the best electromagnets?  (I.e., most powerful when energised. least retained magnetism when de-energised.)
2. What are the best materials for an air-cored electromagnet closed at both ends (such as for an oscillating actuator)?
3. If I use electromagnets along an air-core channel, what should the spacing be?  The strength?  What do the field rise and fall curves look like (so the next can be energised with minimal loss to the falling field of the previous one.  Where in the travel of the magnetic core should one trip on, or off?
4. What sort of material would one use for the slug in an air-cored actuator?  Iron?  Steel?  Ferrite?  A neodymium magnet?

All those, and then I'd like to understand the 'why' (or 'why not') aspects of each.  But I don't know the terminology to ask for what I don't know.

I see I was unclear.

1. What [common] core materials make the best electromagnets?  (Concentrate the field best, but for which the persistence of any induced field is minimal.)
2. What are the best materials (e.g., PVC, paper/cardboard, non-magnetic metal) upon which to wrap windings for an air-core electromagnet?  As in, the hollow cylinder upon which the windings are wrapped?
3. Okey, good to come back to it.
4. If the device in question is a hollow cylinder with multiple successive windings along its length, and the goal is to energise the windings in such a way as to propel or position a slug along the interior of the cylinder, should the slug (presumably of a magnetic material) have its own field, or be made of something in which an induced field is unlikely to persist?

I hope that is better.

And as for learning about magnetism from scratch, StringJunky, what source(s) would you recommend?