AC Electrical Generator Basics - How electricity is generated

electricity is the flow of electrons in a wire the copper wire is made from millions and millions of copper atoms each atom has a free electron this is an electron which is able to move freely between other atoms it does move two other atoms by itself but this occurs randomly in any and all directions which is of no use to us we need lots of electrons to flow in the same direction and we do that by applying a voltage difference across the two ends of a wire this forces the electrons to flow if we reverse the battery the electrons flow in the opposite direction when electricity passes through a wire an electromagnetic field is generated around the wire if we place some compasses around the wire and pass a current through it the compasses will align with the magnetic field if we reverse the direction of current the magnetic field reverses and the compasses change direction if the wire is wrapped into a coil the magnetic field becomes stronger each cross section of wire still produces an electromagnetic field but they combine together to form a larger stronger magnetic field the electromagnet produces a north and south pole just like a permanent magnet if we increase the current to the coil the electromagnetic field increases we can also do the opposite if we pass a magnet through a coil of wire a current is generated in the coil the dial on the ammeter indicates a current flowing in the forward direction this is therefore generating a dc or direct current when the magnet stops moving the dial returns to zero when the magnet is moved in the opposite direction the current flows in the opposite way and the dial indicates a reverse current if we move the magnet in and out repeatedly the current will therefore alternate between flowing forwards and backwards this is how ac or alternating current is generated the current is continuously alternating in direction if we move the magnet faster a stronger current is generated if we use a stronger magnet then the current also increases if we use a larger coil with more turns then this will also generate a larger current instead of using a permanent magnet we could use an electromagnet as we move this in and out it will also generate an ac current in the coil but with the electromagnet we can adjust the current and voltage to vary the strength of the magnetic field this lets us control how much current is generated in the coil instead of moving a magnet in and out of a coil we can generate a current much easier by rotating the magnet and placing the coils around this the strongest part of the magnetic field is at the ends where the magnetic field lines converge you can see the magnetic field lines by sprinkling iron filings over the magnet with the magnet between the two coils there is no current generated but as the magnet starts to rotate the strongest part of the magnetic field gets closer and closer to the coil the coil experiences a changing intensity of the magnetic field this will cause more and more electrons to be pushed forwards up until its maximum intensity then the magnet starts to move away from the coil so the magnetic field begins to decrease and so does the current of electrons until it reaches zero again and now the opposite end of the magnet begins to get closer to the coil and this pulls the electrons in the opposite direction this again reaches a maximum point and then decreases back to zero and so if we were to plot this current on a chart we would get a sine wave with a current flowing in the positive and then the negative regions this setup gives us a single phase ac supply but we have all this empty space between the coils which seems a bit of a waste so what can we do with all this space well we can add more coils to create more phases and provide even more power if we place another coil 120 degrees rotation from the first phase this will give us a second phase why because the coil is at a different angle so it will experience the change in intensity of the magnetic field at a different time the current is therefore going to flow forwards and backwards at a different time that gives us another sine wave which occurs at a different time we still have empty space here so we can add another set of coils at 120 degrees from the previous set to create a third phase if we use just a single phase then for every rotation of the magnet half the time the current is flowing forwards and half the time the current is flowing backwards but with three phases we always have a phase which is flowing forwards and we always have a phase which is flowing backwards which means we can utilize this to provide more power instead of having three separate coils and six wires as the phases are always switching between forwards and backwards we can connect the ends of the coils together the current will then flow freely between each coil as it changes direction okay guys that's it for this video but to continue your learning then check out one of the videos on screen now and i'll catch you there for the next lesson don't forget to follow us on facebook instagram linkedin as well as the engineeringmindset.com

Channel: The Engineering Mindset

Views: 740,812

Keywords: ac generator, alternating current, electric generator, generator, electrical engineering, electricity, dc generator, working principle, electricity basics, electronics engineering, ac power, physics, electronics, industrial engineering, electromotive force, ammeter, electric potential, electrician training, electricity and magnatism, basic electricity, ac generator working, free energy generator, how electricity works, current electricity, online learning, michael faraday, ac, dc

Id: WhATjUHgzxQ

Length: 5min 56sec (356 seconds)

Published: Sat Jul 10 2021