Does AC form a closed loop circuit?

[sophiecentaur]

Could you tell whether undertow is a displacement of a water a few centimeters ahead?

You have to ask yourself what would be the result of a constant net flow in any direction.
Gravity waves (I.e. Waves on a liquid surface) have a longitudinal. component but that is a periodic displacement , only.

 

[justin001]

You have to ask yourself what would be the result of a constant net flow in any direction.
Gravity waves (I.e. Waves on a liquid surface) have a longitudinal. component but that is a periodic displacement , only.

Sorry but I couldn't get what you're trying to say.It might be because I'm totally weak in Physics.I would like to know whether there is at least a minute displacement for the waves that reach the beach?

 

[sophiecentaur]

Did you read the terms "transverse" and "longitudinal" in my earlier post? They are the key to this, I think. Google them or try the BBC Bitesize revision notes. I can only repeat that there can be no net forward flow of medium. The consequence would be a build up over time.

 

[justin001]

Did you read the terms "transverse" and "longitudinal" in my earlier post? They are the key to this, I think. Google them or try the BBC Bitesize revision notes. I can only repeat that there can be no net forward flow of medium. The consequence would be a build up over time.

Do you mean to say about this article: http://www.bbc.co.uk/education/guides/zgr8d2p/revision/1?

 

[sophiecentaur]

Yes. That is one way in. There are links to sound and light.
Calling water waves transverse is actually not accurate but they are often used as an intro because we can see them working. You need to get in the habit of reading around lots when you have a question. Only you know what level of info you need and you can select the most appropriate stuff.

 

[justin001]

Yes. That is one way in. There are links to sound and light.
Calling water waves transverse is actually not accurate but they are often used as an intro because we can see them working. You need to get in the habit of reading around lots when you have a question. Only you know what level of info you need and you can select the most appropriate stuff.

As the article says that "wave moves past you" does this mean that 'water moves past you'?

 

[sophiecentaur]

For a wave on a wiggled string, does the string move past you? Only if you let go and throw it. The 'Medium' is not the Wave.

 

[anaranjo]

There is an analogy for electron movements forward and backward in a conductor: the Newton's Cradle, or Newton Pendulum. The balls (electrons) do not travel. They just transmit the energy. Here a link of many:

 

[Salvador]

I felt maybe I could give a hand at explaining.But any way you need to know or learn if you don't know some of the basics because without them it's hard to explain as it sounds all like a language from Mars.
So in a typical AC generator you have three sets of coils in the stator and a rotating rotor with poles on it formed also by coils.The rotor coils develop a magnetic field creating poles on the rotor much like poles from a permanent magnet.the coils get their current from a set of brushes and sliding contacts called sliprings.Remember a DC motor or generator has what is called a commutator , but AC generators have slip rings.

Usually AC generators are three phase.The angles between phases represent the geometry of the AC generator were the coils are spaced with such angles in the stator.Look at my crude drawing and take for example one of the three coils on the stator, now imagine one of the rotor poles approaching the coil as it rotates , let's say it's the N pole.what you see in that coil is the voltage starts to rise in a sinusoidal fashion because as the rotor pole gets closer to the where the stator coil is the magnetic flux increases through that coil , so the voltage rises when the pole is exactly 1:1 with the middle of the coil that's were the flux stops increasing and the voltage has hit it's peak.Then as the magnet moves away from the closest position the flux lines decrease and the sinus starts to fall and the voltage decreases in the coil.This happens until the voltage hits zero volts and for a very brief moment there is no flux through the coil and no voltage in it but then the next pole , this time S pole again approaches the same stator coil so the magnetic flux starts to increase again , only this time it's the opposite pole so the voltage in the coil begins were the previous pole left it at zero volts and now it descends into the negative side of the sine wave, simply because its the opposite pole so the electrons (which you love) now flow the other direction into the coil.
As this pole again reaches the closest position and the flux is maximum through the coil the sine wave hits the lowest point as the pole moves away again the sine wave starts to rise again to get back to zero volts again and so one full AC cycle has ended and consisted of two half cycles.
two opposite poles rotating by was necessary to create this full cycle each of the poles made one half cycle but each half cycle was with opposite polarity because the poles themselves are opposite so the electron flow reversed direction.
If you understand how each cycle works then you can further see how the three phase AC generator works.It's all basically a matter of a static magnetic field rotating near by fixed coils and a change in magnetic field creates a voltage in a coil.A transformer works the same way it's just that it doesn't need to rotate because the current that makes the field is already changing so the field also changes.
In a generator you have physical movement which then through magnetism creates a changing current in a coil.This is also one of the reasons why in a typical AC generator the output frequency is dependent on it's rotor RPM , do you see why is that so Justin ?

Even in a typical DC generator the current (field) is changing in the output coils , just that the commutator and further addition of capacitors at the output smooths out the otherwise varying voltage/current.

The reason why single phase needs a return wire and three phases doesn't is because in three phase supply the return is managed by other phases because as you see in the workings of a generator , while one phase rises another one falls so to speak of or while the electrons flow in one way in one phase they flow the opposite way in another and this then creates a net flow of power , in a single phase electrons can't flow both directions at the same time in a single wire so two wires form a loop.Actually every loop must consist of atleast two wires, no matter whether it's AC or DC.And even when you think that in the ground case there is just one wire , no the ground is the other wire if it's used in a DC or AC situation , even though it's not common practice to use ground as a conductor because it's conductance varies from place to place.It's only used for safety , or as earthing point in case of accidents.As to the coupling between your house and the generator , No , the wires that power your house only run to the nearest transformer and in the national grid there are tens if not hundreds of transformers between your house and the generator of the closest electricity station.
Once you will learn this then you can start to go further and see that the electrons you are talking about are actually just a medium for something that is unseen to the naked eye , which is the EM field which also is the one that carries the energy , then you will also see that even though not directly via wires but your house is indeed coupled to the generator at the power station via the EM field because that is how every transformer can get power from one winding to another even though these two windings are not electrically or physically connected.

 

[the_emi_guy]

Justin,
Perhaps imagine what would happen if we did *not* provide return path.

Imagine delivering 1A of current from a generator to an automobile sized load without providing for a return path. Within 1 second we will have charged up the load to 1,000 megavolts (assuming 1000pf load to ground capacitance). The idea is that electric charges enforce equilibrium with enormous strength (using Sophiecentaur's analogy, the links in the chain are very strong).

(And even in this case it can be argued that there is still a return path in the form of displacement current through the capacitance)

 

[justin001]

I felt maybe I could give a hand at explaining.But any way you need to know or learn if you don't know some of the basics because without them it's hard to explain as it sounds all like a language from Mars.
So in a typical AC generator you have three sets of coils in the stator and a rotating rotor with poles on it formed also by coils.The rotor coils develop a magnetic field creating poles on the rotor much like poles from a permanent magnet.the coils get their current from a set of brushes and sliding contacts called sliprings.Remember a DC motor or generator has what is called a commutator , but AC generators have slip rings.

Usually AC generators are three phase.The angles between phases represent the geometry of the AC generator were the coils are spaced with such angles in the stator.Look at my crude drawing and take for example one of the three coils on the stator, now imagine one of the rotor poles approaching the coil as it rotates , let's say it's the N pole.what you see in that coil is the voltage starts to rise in a sinusoidal fashion because as the rotor pole gets closer to the where the stator coil is the magnetic flux increases through that coil , so the voltage rises when the pole is exactly 1:1 with the middle of the coil that's were the flux stops increasing and the voltage has hit it's peak.Then as the magnet moves away from the closest position the flux lines decrease and the sinus starts to fall and the voltage decreases in the coil.This happens until the voltage hits zero volts and for a very brief moment there is no flux through the coil and no voltage in it but then the next pole , this time S pole again approaches the same stator coil so the magnetic flux starts to increase again , only this time it's the opposite pole so the voltage in the coil begins were the previous pole left it at zero volts and now it descends into the negative side of the sine wave, simply because its the opposite pole so the electrons (which you love) now flow the other direction into the coil.
As this pole again reaches the closest position and the flux is maximum through the coil the sine wave hits the lowest point as the pole moves away again the sine wave starts to rise again to get back to zero volts again and so one full AC cycle has ended and consisted of two half cycles.
two opposite poles rotating by was necessary to create this full cycle each of the poles made one half cycle but each half cycle was with opposite polarity because the poles themselves are opposite so the electron flow reversed direction.
If you understand how each cycle works then you can further see how the three phase AC generator works.It's all basically a matter of a static magnetic field rotating near by fixed coils and a change in magnetic field creates a voltage in a coil.A transformer works the same way it's just that it doesn't need to rotate because the current that makes the field is already changing so the field also changes.
In a generator you have physical movement which then through magnetism creates a changing current in a coil.This is also one of the reasons why in a typical AC generator the output frequency is dependent on it's rotor RPM , do you see why is that so Justin ?

Even in a typical DC generator the current (field) is changing in the output coils , just that the commutator and further addition of capacitors at the output smooths out the otherwise varying voltage/current.

The reason why single phase needs a return wire and three phases doesn't is because in three phase supply the return is managed by other phases because as you see in the workings of a generator , while one phase rises another one falls so to speak of or while the electrons flow in one way in one phase they flow the opposite way in another and this then creates a net flow of power , in a single phase electrons can't flow both directions at the same time in a single wire so two wires form a loop.Actually every loop must consist of atleast two wires, no matter whether it's AC or DC.And even when you think that in the ground case there is just one wire , no the ground is the other wire if it's used in a DC or AC situation , even though it's not common practice to use ground as a conductor because it's conductance varies from place to place.It's only used for safety , or as earthing point in case of accidents.As to the coupling between your house and the generator , No , the wires that power your house only run to the nearest transformer and in the national grid there are tens if not hundreds of transformers between your house and the generator of the closest electricity station.
Once you will learn this then you can start to go further and see that the electrons you are talking about are actually just a medium for something that is unseen to the naked eye , which is the EM field which also is the one that carries the energy , then you will also see that even though not directly via wires but your house is indeed coupled to the generator at the power station via the EM field because that is how every transformer can get power from one winding to another even though these two windings are not electrically or physically connected.View attachment 101212

Yeah you're right this seems as a "language from mars".I think I should learn the basics and I'll come back.

 

[justin001]

Justin,
Perhaps imagine what would happen if we did *not* provide return path.

Imagine delivering 1A of current from a generator to an automobile sized load without providing for a return path. Within 1 second we will have charged up the load to 1,000 megavolts (assuming 1000pf load to ground capacitance). The idea is that electric charges enforce equilibrium with enormous strength (using Sophiecentaur's analogy, the links in the chain are very strong).

(And even in this case it can be argued that there is still a return path in the form of displacement current through the capacitance)

Do you mean to say that if the same wire is used for supplying and returning electricity there would be electron collisions?

 

[justin001]

There is an analogy for electron movements forward and backward in a conductor: the Newton's Cradle, or Newton Pendulum. The balls (electrons) do not travel. They just transmit the energy. Here a link of many:

Sorry but I couldn't play that video.It might be because You Tube is blocked in our college.

 

[justin001]

For a wave on a wiggled string, does the string move past you? Only if you let go and throw it. The 'Medium' is not the Wave.

Yeah that's right for string but I can't get the picture for water waves.It might be because I'm not that much imaginative.

 

[the_emi_guy]

Do you mean to say that if the same wire is used for supplying and returning electricity there would be electron collisions?

No, what I am suggesting is the hypothetical situation were there was no return path, current flows to the load and is not balanced by any current returning back.

The enormous voltage that would be produced by pumping all of these electrons into the load may help you understand why there must be a return path which allows a balancing amount of electrons to exit the load.

 

[justin001]

No, what I am suggesting is the hypothetical situation were there was no return path, current flows to the load and is not balanced by any current returning back.

Sorry but I couldn't get 'why the current that flows to the load is not balanced by any current returning back'?Could you help me.

 

[the_emi_guy]

Sorry but I couldn't get 'why the current that flows to the load is not balanced by any current returning back'?Could you help me.

Sorry, perhaps my reasoning is a bit too deep. I'm realizing it requires some knowledge of electrostatics.

If we pump negative electrons into a conductor, that conductor becomes charged negatively. This is like static electricity. Turns out that 1A of current flowing for 1 second is a *lot* of electrons. Enough to charge a conductor up to billions of volts. Of course this is impossible, so when we send 1A of current into something, 1A of current must come out of that something. The current that comes back out we can call return current, but as others have mentioned it is really a loop.

 

[justin001]

Sorry, perhaps my reasoning is a bit too deep. I'm realizing it requires some knowledge of electrostatics.

If we pump negative electrons into a conductor, that conductor becomes charged negatively. This is like static electricity. Turns out that 1A of current flowing for 1 second is a *lot* of electrons. Enough to charge a conductor up to billions of volts. Of course this is impossible, so when we send 1A of current into something, 1A of current must come out of that something. The current that comes back out we can call return current, but as others have mentioned it is really a loop.

Could you tell whether 1 coulomb-Volt = billions of volts(approx).I really couldn't get the reason of 'why billions of volts is generated if we charge a conductor'?

 

[Baluncore]

I really couldn't get the reason of 'why billions of volts is generated if we charge a conductor'?

To charge a conductor requires that the conductor must be insulated somehow from it's environment. That makes the conductor one plate of a capacitor while the other plate is the rest of the universe.
Capacitance is defined as the ratio of voltage to charge; C = Q / V.
From that comes; V = Q / C, so to get a huge voltage you need a big charge and a small capacitance.Worrying about the movement of electrons is a distraction. There is a magnetic field wrapped around every current in any wire. By itself that will radiate everywhere. But if there is an equal and opposite return current flowing in another wire, next to the first, the two opposite magnetic fields will cancel away from the two wires, which will prevent radiation. If you do not have a return wire you have an antenna that will radiate the energy instead of guiding it to the load.

 

[jim hardy]

Going back to the original question

Some say that AC should form a closed loop circuit for electricity utilization but is there really an loop from the Power station(hot wire) to the Ground(neutral) and then from Ground to power station so that it forms a loop?

Yes there is such a loop.
But it doesn't usually include "ground"
Plus,
It's not a single loop but a series of closed loops like the links of a chain
each loop connecting two of the transformers in the long distribution chain between the power station and your house.

So the return current from your house doesn't go all the way back to the power plant, only to the transformer on the pole by your house.
That transformer recirculates its high side return current back to the transformer in a switchyard that feeds your neighborhood,
and so on all the way to a power plant somewhere.
Each transformer is the junction of two links.

maybe i should have drawn them linked ?
Naaahh, you get the idea, current doesn't cross the transformer core only energy does...

If there's any current flowing through "Ground" in one of those many links
it's because there's an unbalance, ie currents in the opposite sides of the link aren't equal.

When your studies take you to three phase you'll learn that the links are not simple two wire loops but have three main wires, plus another lesser wire called "Neutral" which is usually earthed by grounding rods.

I hope this oversimplification helps plant the concept. Really it's just Kirchoff.
In today's "Publish or Perish" academic environment textbook authors are forced to "elegantize" it.

...when someone asks a PF question and the resulting overkill can put a chap right off the subject (they can get scared off and never come back with responses).

Kudos to justin001 for hanging in there.Sorry if i have belabored the obvious.
Trying to
"Keep it simple."

old jim

 

[justin001]

To charge a conductor requires that the conductor must be insulated somehow from it's environment. That makes the conductor one plate of a capacitor while the other plate is the rest of the universe.
Capacitance is defined as the ratio of voltage to charge; C = Q / V.
From that comes; V = Q / C, so to get a huge voltage you need a big charge and a small capacitance.Worrying about the movement of electrons is a distraction. There is a magnetic field wrapped around every current in any wire. By itself that will radiate everywhere. But if there is an equal and opposite return current flowing in another wire, next to the first, the two opposite magnetic fields will cancel away from the two wires, which will prevent radiation. If you do not have a return wire you have an antenna that will radiate the energy instead of guiding it to the load.

Oh sorry I'm weak in this field.I'' learn the basics of capacitor and come back to you.

 

[justin001]

Going back to the original question
Yes there is such a loop.
But it doesn't usually include "ground"
Plus,
It's not a single loop but a series of closed loops like the links of a chain
each loop connecting two of the transformers in the long distribution chain between the power station and your house.

So the return current from your house doesn't go all the way back to the power plant, only to the transformer on the pole by your house.
That transformer recirculates its high side return current back to the transformer in a switchyard that feeds your neighborhood,
and so on all the way to a power plant somewhere.
Each transformer is the junction of two links.

View attachment 101238
maybe i should have drawn them linked ?
Naaahh, you get the idea, current doesn't cross the transformer core only energy does...

If there's any current flowing through "Ground" in one of those many links
it's because there's an unbalance, ie currents in the opposite sides of the link aren't equal.

When your studies take you to three phase you'll learn that the links are not simple two wire loops but have three main wires, plus another lesser wire called "Neutral" which is usually earthed by grounding rods.

I hope this oversimplification helps plant the concept. Really it's just Kirchoff.
In today's "Publish or Perish" academic environment textbook authors are forced to "elegantize" it.
Kudos to justin001 for hanging in there.Sorry if i have belabored the obvious.
Trying to
"Keep it simple."

old jim

Yeah thanks for that.To be honest I even couldn't get how 'three phase' works.It's true that academics has destroyed the world of intuitive science at least in a few countries.If I haven't studied that much 'ill science' in high school I might be able to understand the discussion going on here.It's really better to have a plain brain than a brain full of unrelated stuff that turns you in a loop from which you can't never escape.Also I still can't get how generators work.I'm confused with the "coils part" and can't even get why we use coils in generator.

 

[Salvador]

A coil is just a conductor wrapped in a loop , how else do you expect we could generate electricity ?The rotor can even be made of permanent magnets for smaller generators , because it only needs the magnetic field to be there but the generator output must have some sort of a conductor don't you think? Electricity flows in conductors and is also induced in them via changing EM fields.
Just out of curiosity , what was your idea about what lies inside a generator ?

By the way coils and conductors are among the most basic and fundamental parts of any electrical system , just think about it they are in all kinds of motors/generators, transformers, inductors, they make up all the wires running from power stations to homes , also antennas are mostly coils or pieces of wire each with a different length , like the radio you have in your house has that metal stick coming out of it.

P.S. Don't feel bad , many people can learn to wire three phase when they need to attach a motor to it but I think only a handful of them actually understand how the theory works , it's not exactly that easy it takes time and basics to understand all aspects of it.

 

[justin001]

A coil is just a conductor wrapped in a loop , how else do you expect we could generate electricity ?The rotor can even be made of permanent magnets for smaller generators , because it only needs the magnetic field to be there but the generator output must have some sort of a conductor don't you think? Electricity flows in conductors and is also induced in them via changing EM fields.
Just out of curiosity , what was your idea about what lies inside a generator ?

By the way coils and conductors are among the most basic and fundamental parts of any electrical system , just think about it they are in all kinds of motors/generators, transformers, inductors, they make up all the wires running from power stations to homes , also antennas are mostly coils or pieces of wire each with a different length , like the radio you have in your house has that metal stick coming out of it.

P.S. Don't feel bad , many people can learn to wire three phase when they need to attach a motor to it but I think only a handful of them actually understand how the theory works , it's not exactly that easy it takes time and basics to understand all aspects of it.

Yeah that's true.From the lessons I learned from high school when the picture of generator comes into my mind I get an north pole and south place resting on opposite sides with a conductor rotating by the power of water falling on the turbine. I'm really confused with the coil windings in a generator.I can't get where the coil windings are placed in a generator.Also I can't get where the induced current is generated or more precisely in which coil winding electromagnetic induction takes place.

 

[sophiecentaur]

Making connections to a rotating shaft is not convenient, especially when high power. So it is easiest to rotate a magnet (permanent or a low power electromagnet with slip rings) on a shaft and have the output coil(s) fixed. You get the required relative rotation and can shift a lot of power through static cables.

 

[Baluncore]

I'm really confused with the coil windings ...

Maybe you need to take apart an induction motor, a universal motor and a car alternator.
Get some scrap parts. That will show you how the conductor circuits and the magnetic paths are related.

 

[jim hardy]

It's true that academics has destroyed the world of intuitive science at least in a few countries.

I have respect for academics because they build on the steps made by intuitionists . Science leapfrogs ahead because of both. Asimov's "The Gods Theselves" has a digression on the subject. It takes both types.

Also I still can't get how generators work.I'm confused with the "coils part" and can't even get why we use coils in generator.

Generators and motors come down to right hand rule
when you take vectors and study cross product
generator and motor action become intuitive
though simple right hand rule will demonstrate it too.

it's the force on free charges inside the wires
http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magfor.html
see the great picture at that site

well i guess those snobs don't want us using their images.in a generator the charges in the moving wire are pushed longways toward one end of the wire by the magnetic field, making voltage for some external use.
In a motor the charges are moved longways down the wire by external voltage, causing them to push sideways against the magnetic field making torque .
really it's that simple

old jim

 

[George K]

Some say that AC should form a closed loop circuit for electricity utilization but is there really an loop from the Power station(hot wire) to the Ground(neutral) and then from Ground to power station so that it forms a loop?

Don't be confused. Always there must be a closed loop for a current (DC or AC) to flow. The voltage (as provided by a voltage source) is just the "tendency" of the electrons to flow. But the electrons will never flow unless -somehow- the two poles of the voltage source form a closed loop. This will happen by connecting a load (a bulb, a motor, a heater e.t.c.) to the poles so that the electrons will be able to flow (from one pole of the other). And this the current. For example, connect one lead of a lamp to the + pole of a battery and the other lead of the lamp to the ground. Does any current flow through the lamp? No, it doesn't. (Electrons will not "come up" from the ground by themselves.) You should, also, connect the - pole of the battery to the ground in order to form a closed loop for the current to flow (assuming, ideally, that the "ground" is a very good conductor).

 

[justin001]

Don't be confused. Always there must be a closed loop for a current (DC or AC) to flow. The voltage (as provided by a voltage source) is just the "tendency" of the electrons to flow. But the electrons will never flow unless -somehow- the two poles of the voltage source form a closed loop. This will happen by connecting a load (a bulb, a motor, a heater e.t.c.) to the poles so that the electrons will be able to flow (from one pole of the other). And this the current. For example, connect one lead of a lamp to the + pole of a battery and the other lead of the lamp to the ground. Does any current flow through the lamp? No, it doesn't. (Electrons will not "come up" from the ground by themselves.) You should, also, connect the - pole of the battery to the ground in order to form a closed loop for the current to flow (assuming, ideally, that the "ground" is a very good conductor).

So do you mean to say that electrons come from the "ground" but not from the '-' pole of the battery that has excess of electrons?I thought that electrons flow from the '-' pole of the battery to the '+' pole of the battery due to the attraction of electrons towards an place where there is '+' charges.Is there a salt bridge in battery?I think the flow of electrons continue indefinitely because of the salt bridge.

I learned these concepts but not the salt bridge from this video:

 

[justin001]

I have respect for academics because they build on the steps made by intuitionists . Science leapfrogs ahead because of both. Asimov's "The Gods Theselves" has a digression on the subject. It takes both types.

Generators and motors come down to right hand rule
when you take vectors and study cross product
generator and motor action become intuitive
though simple right hand rule will demonstrate it too.

it's the force on free charges inside the wires
http://hyperphysics.phy-astr.gsu.edu/hbase/magnetic/magfor.html
see the great picture at that site

well i guess those snobs don't want us using their images.in a generator the charges in the moving wire are pushed longways toward one end of the wire by the magnetic field, making voltage for some external use.
In a motor the charges are moved longways down the wire by external voltage, causing them to push sideways against the magnetic field making torque .
really it's that simple

old jim

Oh sorry I couldn't get that.I couldn't see any 'coils' in this image.To be honest I couldn't get the rules but I think first I might need to know how a generator works and then it might be better to study about the rules.Is this rule found by experiments or is there any theoretical evidence for these rules?

 

[justin001]

Maybe you need to take apart an induction motor, a universal motor and a car alternator.
Get some scrap parts. That will show you how the conductor circuits and the magnetic paths are related.

Yeah that's right but at present I don't have these in my hand or at home.

 

[justin001]

Making connections to a rotating shaft is not convenient, especially when high power. So it is easiest to rotate a magnet (permanent or a low power electromagnet with slip rings) on a shaft and have the output coil(s) fixed. You get the required relative rotation and can shift a lot of power through static cables.

Could you tell where the coils are fixed?I'm confused with where the coils are placed in a generator and which part of the generator that has coils produce induced voltage?

 

[Baluncore]

You should be aware that there are pictures of motors and generators available on the web.
https://en.wikipedia.org/wiki/Universal_motor
The stator and/or armature is a magnetic material with longitudinal slots on the gap surface. Each coil is formed as a rectangle, bent and placed in two slots far apart. The parts of the coil outside the slots cross the end of the magnetic material. The magnetic material between the slots forms the poles of the magnetic field that cross the gap.

 

[justin001]

You should be aware that there are pictures of motors and generators available on the web.
https://en.wikipedia.org/wiki/Universal_motor

Sorry but those images are too complex.It might be because I haven't studied the basics of generators and motors.

 

[Baluncore]

Sorry but those images are too complex.It might be because I haven't studied the basics of generators and motors.

Then pull your finger out and go study the basics of generators and motors.

 

[justin001]

Then pull your finger out and go study the basics of generators and motors.

That's right.

 

[George K]

So do you mean to say that electrons come from the "ground" but not from the '-' pole of the battery that has excess of electrons?I thought that electrons flow from the '-' pole of the battery to the '+' pole of the battery due to the attraction of electrons towards an place where there is '+' charges.Is there a salt bridge in battery?I think the flow of electrons continue indefinitely because of the salt bridge.

I learned these concepts but not the salt bridge from this video:

No, I didn't mean that. Read my answer more carefully. I said:
"Electrons will not "come up" from the ground by themselves. You should, also, connect the - pole of the battery to the ground in order to form a closed loop for the current to flow."
In my example the + pole is connected to the one side of the load (through a wire) and the - pole to the other side of the load (through the ground). So, in this way, a closed loop between the two poles of the battery is formed and (only then) a current flows through the load.

 

[justin001]

No, I didn't mean that. Read my answer more carefully. I said:
"Electrons will not "come up" from the ground by themselves. You should, also, connect the - pole of the battery to the ground in order to form a closed loop for the current to flow."
In my example the + pole is connected to the one side of the load (through a wire) and the - pole to the other side of the load (through the ground). So, in this way, a closed loop between the two poles of the battery is formed and (only then) a current flows through the load.

Yeah that's right.I really meant to say about 'neutral' but I accidentally said it's from the 'ground' as from this post:https://www.physicsforums.com/threads/does-ac-form-a-closed-loop-circuit.872245/#post-5477351.I think now it's clear.