How does a magnet work in a dynamo?

Answer 1

First I'll explain what it is then comes the operational stuff.Another name for it and one which really explains what it does is "Rotary convertor".It consists of an electric motor with an extra set or sets of windings on the Armature,the part that rotates.The motor part is connected to the supply voltage.12v in cars and 28v in aircraft where many of them were used.The remaining windings spinning on the armature would give 200 to 500 volts to run radio or guidance equipment which back in the day was all vacuum tube type. The field was excited by the 12 or 28 volt supply and the secondary windings of the armature had many more turns to develop the high voltages necessary.Efficiency was not very good but reliability was exemplary.Some of these units are still working today, nearly 70 years later.Try that with your CD player!!The Dynamotor,being a compact one piece unit saved weight and space in many a B-17 bomber of WW II.The alternative would be a separate motor to spin the generator or dynamo,as they were once called.Hence the name Dynamotor.Hope this helps

Answer 2

Quick Answer:

A classic dynamo generates electricity by using a rotating coil of wire that passes near magnets which causes current in the wire. That current can do work and so power can be extracted from a dynamo driven by an external source like a waterfall.

The basic physical principle is known as "induction."

Short explanation:

The electrons in the wire feel a force, the magnitude of which is given by the velocity of the wire perpendicular to the magnetic field lines. (There is no force resulting from charges moving parallel to a magnetic field.)

There is a simple equation for the force on a moving charge in a magnetic field.

A charge, q, is being carried in the wire by the movement of the wire with a velocity, v, perpendicular to a magnetic field, B, and it feels a force, F.

F=qvB

(Of course, if there is an electric field present, that too has a force and you have to add it to the force due to the magnetic field.)

This force pushes the charge through the wire and so the force does work and energy can be extracted form the dynamo.

More explanation:

A few centuries ago, Faraday discovered that if you moved a wire loop near a permanent magnet, the loop had electrical current generated in it.

At the time, no one expected such a thing and it led to the discovery of new and more generalized forms of the laws of electromagnetism (laws of electric and magnetic fields).

We now understand what is happening. They already knew that an electric field would exert a force on a charged particle. That is how a battery creates current in a wire. The ends of the battery have a voltage created from the chemical energy in the battery. The electric field is determined by a voltage and is the voltage divided by the distance, or better, the voltage is equal to the electric field times the distance over which the field exists. (V=E.d)

In any case, the electric field created between the two ends of a wire acts on the charges in the wire and they each feel a force equal to the charge times the field.

F=q E

Well, Faraday saw something like that happened when there wasn't any battery creating a field but the the process causing it was the motion of the wire relative to the magnetic field. And, one of the most dramatic chacteristics was that it did not matter if you held the wire and moved the magnet or you held the magnet and moved the wire. You still got a current induced in the wire moving perpendicular to the magnetic field.

This led, back then, to Faraday's law of induction.

Faraday's Law: The induced electromotive force in any closed circuit is equal to the negative of the time rate of change of the magnetic flux through the circuit.

The "electromotive force" is what Faraday called equivalent of the voltage that would be required of a battery to move the same current. (It is a historical thing that voltage and the word force did not get straightened out clearly until later and we still give the name "electromotive force" largely out of respect for the history of discovery.)

The "magnetic flux through the circuit" was the magnetic field strength time the area inside the loop formed by the circuit where the current was measure. (Again, only that part where they are perpendicular. You multiply the component of the magnetic field that is perpendicular to the surface whose edges are defined by the loop of the circuit.

Basically, Faraday's Law of Induction was simple a statement of what was "discovered." It just happened in the lab and he (and others) worked out the quantitative characterization of when it happened and how strong and so forth. The "law" is really a law of Nature, not Faraday. He was just the one reporting it.

The original dynamo designs used the law pretty much exactly as it was discovered, making giant coils of wire rotate on a shaft surrounded by huge permanent magnets. There was a lot of electricity generated this way. Modern power plants still generate electrical power with the Law of Induction, but the permanent magnets are replaced by electromagnets and there is some electronic circuitry involved in controlling currents.

Even so, modern wind farms and hydroelectric plants and hand generators for home all still employ magnets and wires moving and it is still the law of induction at work.

Answer 3

In a dynamo, a magnet creates a magnetic field that interacts with coils of wire to produce electricity through electromagnetic induction. As the magnet spins within the dynamo, it generates a changing magnetic field that induces a current in the coils of wire, resulting in the production of electricity. This electricity can then be used to power various devices or be stored for later use.