Several electromagnet questions

In summary, the conversation revolved around questions regarding the use and properties of electromagnets. The speaker, a firefighter, was seeking help in building something that required the use of electromagnets. Some of the topics discussed included how the polarity of an electromagnet is determined by the direction of current flow, the effects of increasing electrical input on the strength of the magnetic field, the materials that can be used to make magnets and whether they can be welded to, and the availability of electromagnets for purchase. The conversation also touched on the possibility of shielding or canceling out magnetic fields, with the conclusion that there is no surefire way to do so, but some methods may help to concentrate or reduce the field.
  • #1
6fthook
1
0
Hello guys/gals

I have a few questions regarding electromagnets that I'm hoping you can shed some light on for me. I don't know much about physics, magnets, etc. I am a career firefighter that is trying to build something requiring the use of electromagnets.

1. I'm trying to have an electromagnet be able to repel another magnet (not electromagnet). When I electrically charge the electromagnet, does it automatically have a N and a S pole? Can I change what side is which? Also, is it constant which side is which when I charge it or does it change?

2. If I put more current to the electromagnet, does the repelling force increase?

3. What exactly are magnets made of? Can I weld other metals to it?

4. Is there a good place online to purchase magnets/electromagnets? I'm looking for about 2" diameter and 1" or 2" height cylinder.

5. Is there any material that can cancel the magnetic force? Example, some kind of material that I can wrap around the electromagnet and magnet to cancel out the magnetic field so it doesn't affect other things around it?


Hopefully everything made sense. I'm sure I'll think of a few more questions in the near future.

Thank you so much for any help you can provide.
 
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  • #2
Welcome to PF, 6fthook. (Honestly now, isn't that an exaggeration? :rolleyes:)
The polarity of an electromagnet is determined by which way the current is flowing. Swapping positive and negative connections changes the field orientation.
Increasing the electrical input does indeed strengthen the field, but be careful not to overload your windings.
Lots of different materials can be used to make magnets. The easiest and cheapest is iron or steel. Other metals can be welded to it.
EftonScience (formerly Edmund Scientific Co.) used to sell an electromagnet of approximately the size that you specified. It ran on 2 'D' cells and had a 500lb. lifting capacity. I haven't seen a catalogue in decades, so I don't know if it's still available.
 
  • #3
There isn't a way to shield against magnetic fields like you can with electric fields. The best you can do is have a high mu material wrapped around the magnet to try and concentrate most of the field in the high mu. Another method is to have a second magnet that approximately cancels out the original magnetic field.
 

Related to Several electromagnet questions

1. What is an electromagnet?

An electromagnet is a type of magnet that is created by running an electrical current through a wire coiled around a metal core. When the current flows through the wire, it creates a magnetic field around the metal core, making it behave like a magnet.

2. How does an electromagnet work?

An electromagnet works by using the principles of electromagnetism. As an electrical current flows through the wire, it creates a magnetic field around the metal core. The strength of the magnetic field can be controlled by adjusting the amount of current flowing through the wire.

3. What are some common uses of electromagnets?

Electromagnets have a wide range of uses in various industries. They are commonly used in motors, generators, speakers, and transformers. They are also used in medical devices such as MRI machines and in everyday objects like doorbells and refrigerators.

4. How can the strength of an electromagnet be increased?

The strength of an electromagnet can be increased by increasing the number of wire coils around the metal core, increasing the amount of current flowing through the wire, and using a core material with a high magnetic permeability.

5. Can electromagnets be turned off?

Yes, electromagnets can be turned off by stopping the flow of current through the wire. Without an electrical current, the magnetic field around the metal core will disappear, and the electromagnet will no longer act as a magnet.

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