1. Most current generators have rotors with magnetic poles. Anyway, as long as there is relative motion, it can generate electricity, especially for high-power generators. poles. Due to the excitation current, it is much smaller than the current generated by electricity. Of course, the current through the brush must be smaller, and if it is a permanent magnet, even the brush is omitted. The permanent magnet is that it does not consume energy to excite. But the magnetic field strength is not high and the magnetic field intensity cannot be adjusted, so permanent magnets are only used in small-power generators, and electromagnetic magnets are used in large-power generators .
2. Sorry, I'm studying mechanics. Yes, although you have to learn the engine part, but it's not as in-depth as those who specialize in moteurs.
3. When current appears in the coil, the resistance torque acting on the rotor will be greater than that without load. Much more important is just friction torque, but the current in the coil means that. there is an energy conversion and the mechanical energy is converted into electrical energy. The work done by the additional torque is used to convert into electrical energy. The principle is that the live wire will receive a force in the magnetic field. this principle, and the generator rotor is also affected by this force.
4. It exists in theory, but it's still in theory, and it uses ionized plasma that generates electricity as it moves steadily. a magnetic field, but it is still in theory and the reality has not yet appeared. First stage nuclear power generation always converts nuclear energy into thermal energy and then drives the generator through agas turbine, which is different from a thermal power plant. Others are just batteries and cannot be considered generators, such as solar cells, which have practical applications and home power supply, but efficiency. The number of solar cells is currently very low, 20% is already very high, and it is extremely expensive and is only used in satellites. There are also fuel cells, which are still at the laboratory stage and have not yet been developed on a large scale. scale.
I don't know the speed of electrons, but the current speed is indeed close to the speed of light, 300,000 kilometers per second
The current speed does not tell how fast an electron can travel from the power plant to the user. This is the speed at which the process takes place between the moment the electric field is generated and the moment when the electrons begin to move steadily.
There is a very striking metaphor, which is also transferred from the Baidu Encyclopedia:
“This can be understood from This way, as if there is a tube filled with soybeans when a soybean is inserted from one end, one immediately comes out from the other end. is equivalent to the speed of current propagation; and when you look at some grain in the tube alone, the speed of movement is very low. "
Alternating current refers to a voltage or current that has a definite direction and direction. The amplitude changes periodically over time. It has nothing to do with wires. Its direction is determined by the generator.
You may be wondering why the current in both forward and reverse directions can be "used" should it not be sent from the power plant for the users? canuse it?
A common analogy: rub your legs several times with your hands, first from top to bottom, which is the positive direction, then from bottom to top, which is the negative direction, and finally from top to bottom. . , RIGHT! It's alternating current. Have you noticed this everywhere you go? In one direction, just rubbing your legs will make them hot? The same goes for electric current. As long as it flows through the conductor in any direction, it can work.
You can also understand it as the generator "driving" the electrons to oscillate "forward-backward." -forward-backward" in the conductor. Let the user generate force or heat, which is alternating current