Magnet and Coil Stuff?

Question

I am trying to get some voltage out of a coil. The coil is wrapped around a PVC pipe. I have a 8" stack of magnets that will be moving. What are the specifics on how to get some juice out of it?
I'm having serious troubles. Can the coil wires be touching?

Answer 1

Since you mention that you want to move the magnets inside the tube, it appears you know that you want to create relative motion between a conductor and a magnetic field. This relative motion induces a current in the conductor. The difference in electrical potential created from this current flow is the voltage that is produced. Picture the magnets being combined to produce effectively one magnet. Now picture the magnetic field from this magnet. Do the same with coil wires touching. They essentially become a rough cylinder. You can still get relative motion if you can move the magnets fast enough, but it won't be very effective.

Check out this site for more ideas on your project: http://www.sciencebuddies.org/mentoring/project_ideas/Elec_p020.shtml?from=Home

Search terms you can use to better understand the principles:
Electromagnetism
EMF
Faraday
Relative motion between conductor magnetic field

Answer 2

First the wire cannot touch itself if it is not insulated. If it has metal to metal contact it is no longer a wire but a chunk of metal, and that will not produce electricity.

When a coil of wire is passed through a magnetic field, or a magnetic field passed through a coil of wire an amount of electricity will be produced. If you hook a Volt/Ohm meter to the two ends of the wire you will notice a small deflection in the meter needle. If you move the coil or magnet rapidly you will see the needle look like it is vibrating.Moving the coil inwards produces either a positive or negative current flow, moving it outward will produce the opposite flow.
The amount of electricity depends mainly on two things. First, the number of windings of wire. A thin wire will produce the same amount as a large wire. It is the number of loops, not the size of the wire. The second thing is the strength of the magnetic field. The stronger the magnet field the stronger the current flow and amount electricity. The magnetic field can also be increased by winding the wire around an iron core. The iron will concentrate the magnetic field and again produce more. The iron core must also be insulated from the wire.

Radio shack sells the type of insulated wire you need.It has an extremely thin coating of shellac on it to keep it from shorting out. They also sell iron cores.

Answer 3

You need a change in magnetic field to induce a voltage in a coil. If you are moving a stack of magnets back and forth, the field may be changing very little. Only at the ends of the stack will the field change greatly. Try your experiment with just a 1" stack of magnet ( or just one magnet) and move it back and forth so that it is completely out of the coil and then back in and through the other side. This should induce a measureable voltage.

Answer 4

Hopefully, the coil is what is often referred to as "magnet wire" - i.e. the wire is covered with a thin coating of shellac which insulates each wire from shorting out. You have to carefully clean each end to remove this insulation to get a good contact to your meter. If the wire is the proper kind and the magnets are moved rapidly through he tube, a voltage will certainly be produced in the coil.
Depending on all kinds of factors, the voltage may be slight - but if you set your meter on the ohms setting and select a scale that puts the needle near the center, you should see a great difference in the resistance when the magnet is moved through the tube.
Good luck and happy experimenting!

Answer 5

A coil of twine is wrapped round a bar magnet so as that when a cutting-edge flows via the coil, a rigidity is generated which pushes and pulls on the speaker cone, generating sound waves.

Answer 6

The magnets must not touch the coil and the coil must be magnetic to create a magnetic field for the other magnets to spin in.