# How does the shape of an electromagnet pole affect the field produced?

• ptabor
In summary, the tapered shape of the electromagnet pole affects the field produced. The field is strongest at the tip of the pole, but is less dense overall.
ptabor
I'm attempting to get a rough estimate on how the shape of an electromagnet pole will affect the field produced. Most of the poles you see in labs are tapered, and not simply cylindrical - I'm wondering how this affects the field. After all, there has to be a reason why they would do such a thing.

physically, I imagine that a very very narrow pole would have field lines concentrated strongly at the tip, giving a high B density but at the expense of uniformity. On the other side of the coin, a large flat cylinder will have field lines which are less dense, but more uniform.

My understanding falters in the middle, with a "conical" shaped pole.

If anyone can provide some insight i would be appreciative

Magnetic circuit design, with open poles, tends to be a black art.
Less so for closed magnetic circuits.
The rules for magnetic circuits are much like those for electric circuits.
As I understand it, some of the recent software can do a fair job of modeling, but there are no closed form solutions due to somewhat ambiguous multiple leakage paths.

My guess is that a larger core has less saturation, so tapering the core can reduce field leakage over the body of the coil, giving an effective increase in field strength at the pole.

hmm. I thought I posted an analytic solutions, or sorts, here.

Phrak said:
hmm. I thought I posted an analytic solutions, or sorts, here.
There were a bunch of these mag questions all at once, you posted to a lot of the other ones.
I don't remember you posting to this one.

I think there are commercial products that can get an iterative approximation to a question like this.
If you have an analytic solution feel free to post it.
AFAIK, there are only analytic solutions for closed magnetic circuits.

NoTime said:
There were a bunch of these mag questions all at once, you posted to a lot of the other ones.
I don't remember you posting to this one.

I think there are commercial products that can get an iterative approximation to a question like this.
If you have an analytic solution feel free to post it.
AFAIK, there are only analytic solutions for closed magnetic circuits.

Thanks, NT. Re:analytical; I think I've been abusing the language

The magnetic field is had by summing over infintesimal dipoles, but which way do they all point? If I had to, i'd approach the problem like this: assuming no hysteresis, the minimum energy occurs when there's no torque on any dipole, so it may amount to finding the extremal in one variable, the energy. It's a two dimensional problem in r and z, with the diople magnitudes scaled by r.

I'm actually more curious as to how this is normally calculated, then my own suppositions, so I wonder if this is the usual method.

## 1. What is the purpose of designing an electromagnet pole?

The purpose of designing an electromagnet pole is to create a magnetic field that can be controlled and used for various applications. This includes lifting and moving heavy objects, generating electricity, and controlling the movement of electric motors.

## 2. How does the shape of an electromagnet pole affect its performance?

The shape of an electromagnet pole can greatly affect its performance. A cylindrical shape is often preferred as it allows for a more uniform and concentrated magnetic field. However, the shape can vary depending on the specific application and desired strength of the magnetic field.

## 3. What materials are commonly used for electromagnet poles?

The most commonly used material for electromagnet poles is iron or steel, as they have high magnetic permeability and can easily be magnetized. Other materials such as nickel, cobalt, and certain alloys may also be used depending on the specific properties needed for the application.

## 4. How are the dimensions of an electromagnet pole determined?

The dimensions of an electromagnet pole are determined by several factors, including the desired strength of the magnetic field, the available power source, and the space limitations of the application. The number of turns in the coil and the distance between the pole and the object to be magnetized also play a role in determining the dimensions.

## 5. Can the design of an electromagnet pole be optimized for different applications?

Yes, the design of an electromagnet pole can be optimized for different applications. Factors such as the shape, material, and dimensions can be adjusted to achieve the desired strength and direction of the magnetic field for a specific use. This allows for versatility and adaptability of electromagnets in various industries and fields of research.

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