Introduction to the principle of magnet power generation, Free electrons in a conductor are subject to the Lorentz force
According to the law of conservation of energy, energy cannot be generated without reason, nor can it disappear without reason. The electric energy generated by magnets must come from other forms of energy. Physics tells us: the process of an object doing work is the process of energy conversion. The electric energy generated by the magnet is obtained by external objects acting on the generator to convert other forms of energy into electric energy. The device that uses magnets to generate electricity is mainly a generator. The energy that works on the generator can be the mechanical energy of water, or the chemical energy consumed by a heat engine (gasoline engine, diesel engine, steam turbine, etc.).
During the rotation of the generator, the rotor cuts the magnetic induction line to do work, so that the electrons in the conductor move directionally under the action of the magnetic field to generate an induced electromotive force (voltage). When the circuit is closed, an induced current will be generated. Of course, only a part of this work is converted into electrical energy. magnet power generation
From a microscopic point of view, when a part of the conductor in the closed circuit moves relative to the magnetic field, the free electrons in the conductor move together with the conductor and are subjected to the Lorentz force, causing the free electrons to move in a directional manner to form a current. It can also be understood in this way: when the magnetic field passing through the closed circuit changes, an electric field is generated around the magnetic field, and the electric field makes the free electrons in the conductor move in a direction to form a current.
The size of the generated current (or the level of the induced voltage, or the amount of electric energy generated) is related to the number of turns of the coil, the strength of the magnetic field of the magnet, and the speed of the rotor. The more turns, the stronger the magnetic field, and the faster the rotor speed, the more electrical energy is generated and the more mechanical energy is consumed.
The composition of the magnet is iron, cobalt, nickel, boron, neodymium and other atoms, and its types include neodymium iron boron magnets, samarium cobalt magnets, alnico magnets, ferrite magnets, permanent magnets, and artificial magnets. Among them, NdFeB magnets are known as the king of magnetism and have the strongest magnetism. The working temperature of AlNiCo magnets can be as high as 600°C, and the materials of SmCo magnets are expensive, but they are more suitable for working in high temperature environments. Artificial magnets are the most common magnets in life. magnet power generation
A part of the conductor of the closed circuit cuts the magnetic induction line in the magnetic field, and the phenomenon that the current will be generated in the conductor is called the electromagnetic induction phenomenon, and the generated current is called the induced current.
There are five types of induced currents: changing current, changing magnetic field, moving constant current, moving magnet, and conductor moving in a magnetic field.
There are two conditions for the induction current: a closed circuit and a change in the magnetic flux passing through the closed circuit. In the absence of one condition, there will be no induced current. Calculation method: Assume that the closed circuit is a coil with n turns, ΔΦ is the amount of change in magnetic flux, Δt is the time it takes for the change to occur, and E is the induced electromotive force generated. Then the induced electromotive force is calculated as E=nΔΦ/Δt, the magnetic flux Φ=BS, B is the magnetic induction intensity of the uniform magnetic field, and S is the facing area, which is Faraday’s law of electromagnetic induction. You can also use the calculation formula for cutting the magnetic field line movement: E=BLVsinα. magnet power generation
The maximum induced electromotive force of the alternator Em=nBSω. The magnetic field generated by the induced current must hinder the change of the magnetic flux that causes the change of the induced current.
Electromagnetic induction is mainly used in dynamic microphones, tape recorders, car speedometers, motors, transformers, etc.