240v debate....

[Besoeker]

Congratulations. You got all that exactly backwards. :slaphead:

Yes. I ought to be surprised.
But rather disappointed that I am not.

 

[Rick Christopherson]

In post #433, you claimed
"that your circuit, as drawn, is wrong."
Please post why YOU think is a correct version.
Without dancing around the topic.

You drew a nodal diagram for your source, but you don't know what a nodal diagram is. I do not have the patience to play games with someone pretending to be something they are not. If you had not come back with a smart alec answer, I would have just let it go, and your guise would not have been revealed.

 

[hurk27]

Actually, that's the anode. As drawn, the cathodes are connected to each other and form the positive leg of the load.
Of course, a certain member claims that my drawing is wrong so, I extend you the same invitation. Draw it as how you think it should be.

Correct my mind is playing trick I did swap anode and cathode,:happyyes:

and your drawing is correct also if the center tap transformer is in phase.

I think the problem is the time line, what is what at a given point in time, when I laid out the post I described the time line as 90? and 270? as to when Ia and Ib is positive respectively, if both Ia and Ib were positive at the same time then the SCR firing would be at the same time and would result in a single firing per cycle, lets put this on the side for a moment and conceder what is a in-phase circuit, would not a in-phase circuit have a positive on one conductor and a negative on the other at a given point in time?

If the above is true then so is the time line on a center tapped transformer when Ia is positive then Ib is negative, to say other wise would be a contradiction, now if Ia and Ib is in-phase, then Ian and Inb must also be in-phase or the SCR/diode circuit would not function as both SCR's/diodes would fire at the same time, it is the function of the center tap transformer being in-phase that allows one diode to fire each half cycle during the time line.

 

[mivey]

I think the problem is the time line, what is what at a given point in time, when I laid out the post I described the time line as 90? and 270? as to when Ia and Ib is positive respectively, if both Ia and Ib were positive at the same time then the SCR firing would be at the same time and would result in a single firing per cycle

Which is obviously not what Besoeker was stating. To interpret the drawing that way is to purposely try to mis-understand.

lets put this on the side for a moment and conceder what is a in-phase circuit, would not a in-phase circuit have a positive on one conductor and a negative on the other at a given point in time?

And that is an issue: a circuit is neither in phase nor out of phase. You must define a direction before you can define in or out of phase. That brings up the next issue: there is no universal direction.

If the above is true then so is the time line on a center tapped transformer when Ia is positive then Ib is negative, to say other wise would be a contradiction, now if Ia and Ib is in-phase, then Ian and Inb must also be in-phase or the SCR/diode circuit would not function as both SCR's/diodes would fire at the same time, it is the function of the center tap transformer being in-phase that allows one diode to fire each half cycle during the time line.

Ia and Ib can not be said to be in phase or our of phase with anything until you specify the direction.

Polarity and direction are not the same thing. The polarity does not indicate the "correct" direction. The only thing polarity does is tell you which way the electrons in one part of a circuit are moving relative to electrons in another part of a circuit at a given instant in time. A voltage is just a potential difference and can be taken in either direction. Nothing says there is a universally "right" and "wrong" direction and polarity marks sure don't tell you that.

 

[mivey]

Nothing arbitrary about it. It's how things work in real life.

And because you have made a decision about how the voltages are going to be used, that removed what would have been arbitrary. I may have a different circuit that uses the voltages in a different arrangement. Both of us would be using the same forces but in different directions.There is nothing that would say my circuit is "right" over yours being "right" because they are both valid uses of real voltages.

I can't believe this is so hard for others to get. It is basic electric theory, not some voodoo that we have just invented during the course of these discussions. As for the flux comments I keep hearing: there is no voodoo going on there either. The flux does not completely define in what direction we must take the force (not THAT force ).

 

[jwelectric]

I thank each of the posters in this thread as it is growing into that all elusive 1000 post thread but even though it is growing rapidly I just can?t see what some of you are trying to say that has one iota to do with the original post

I wanted to run a pump at 240v vs 120v, for obvious reasons, voltage drop, wire size, etc. But... I get this a lot from people, 240v is more dangerous. So I'm looking for a better way to explain to people that its just as safe as a 120v circuit but with better benefits.

This question is directed to a single phase 120/240 volt transformer and some of the answers has went into two separate generators producing 120 volts all the way to three phase power plants producing DC voltages. None of which addresses the 120/240 volt circuit in question.

I am beginning to think that none of you have any clue as to what you are talking about and are just listening to your heads roar instead of sticking to the simple 120/240 volt transformer which will have a ?single phase? supplying the load.

There seems to be the belief that there is really two phases of 120 volts that oppose each other at 180 degrees and some that believe as I do that the name of the panel to which all this connects tells the story, ?single phase? that is always in tune with itself and never opposing itself.

Please do not let up as two things are occurring, 1- we might reach that all elusive 1000 post thread and, 2- I have never laughed so much or so hard. The phrase that laughter is the best medicine is true as I have felt the best in the past week as I have in several years.

 

[mivey]

I thank each of the posters in this thread as it is growing into that all elusive 1000 post thread but even though it is growing rapidly I just can?t see what some of you are trying to say that has one iota to do with the original post

This question is directed to a single phase 120/240 volt transformer and some of the answers has went into two separate generators producing 120 volts all the way to three phase power plants producing DC voltages. None of which addresses the 120/240 volt circuit in question.

It is kinda related and I made the stretch here:

I think it is a fair question to ask: "if the line-to-ground voltage is essentially 120 volts for both 120 and 240 volt systems {at least for the ones we normally see}, how do we still get 240 volts?". One must understand the relationship between voltages that have a grounded neutral reference (X2 & X3 grounded neutral). In this line of questioning, an X1 or X4 reference would not be as clear.

I am beginning to think that none of you have any clue as to what you are talking about and are just listening to your heads roar instead of sticking to the simple 120/240 volt transformer which will have a ?single phase? supplying the load.

Does anybody really know much of anything? We are beings living in a vast universe that we barely understand. We gain some knowledge and make bold declarations about how right or wrong something is. What we know and what we think is nothing compared to the knowledge of the One who made our universe.

There seems to be the belief that there is really two phases of 120 volts that oppose each other at 180 degrees and some that believe as I do that the name of the panel to which all this connects tells the story, ?single phase? that is always in tune with itself and never opposing itself.

Any voltage can have a direction defined to be the direction of push and the direction of pull. We say a push is when the potential rises across the source in the same direction that current flows from the source feeding the load (the generator pushes current to the load). In Besoeker's circuit, he wants to use the "push" from n to a and the "push" from n to b.

At a specific point in time at any point inside the two-terminal single-phase AC source, carriers are being pulled from one direction and pushed in the other (like the bucket brigade in a fire line). We say they are all moving the same way, and although it is a net movement concept, we say all sections are all "in-phase" if we use the same direction for all sections.

The fact that the electrons (the net movement) are all moving the same way does not mean we have to consider all of the forces as pushes or all of the forces as pulls. The fact is that the same force that can create a push in your circuit is the same force that can create a pull in your circuit. To say one way is real and the other is a math trick is to say the the force itself is a math trick because it is only one force that does the pushing or pulling across the two terminals. If you do not understand that, you do not understand how electricity works.

Please do not let up as two things are occurring, 1- we might reach that all elusive 1000 post thread and, 2- I have never laughed so much or so hard. The phrase that laughter is the best medicine is true as I have felt the best in the past week as I have in several years.

I am here strictly for my own enjoyment. I like threads like this because they make you think and work on your communication skills.

 

[jwelectric]

Does anybody really know much of anything?

Well now I must not have enough education to understand all this push and pull.

I was under the impression that there were two different theories of how electrons moved around a circuit and they were as follows, Electron flow where electrons move from negative to positive and the conventional flow where electrons flow from positive to negative.

What I have not learned as yet is that anything is pushing or pulling anything. The way is see it is the electrons are moving from one potential to the other.

I also have a hard time seeing now in a single coil of wire how something can be pulling and pushing at the same time half way through the coil of wire. Take away the induced counter voltage and look at the wire as one straight piece of wire how can the electrons be pushed half way through then all of a sudden the electrons start being pulled?

Maybe I just figured it out. The first half the electrons are doing the electron flow thing and the second half they are doing the conventional flow thing. Yea I can see it clearly now.

 

[jim dungar]

And I am stating that Van and Vbn are mutually displaced by 180deg.
Do you dispute that?

Yes, I have stated this previously, the math is Van+Vnb = Vab = Van-Vbn, therefore Vnb=-vbn and so Vab = Van-(-Vnb).


Again I am discussing the real life of a single winding transformer not the application of mathematics.
What dictates the actual relationship between the flux of the core and the voltage between any two points on the winding; physics (i.e. Faraday's Law) or how things are viewed (i.e. measured)?

 

[mivey]

Well now I must not have enough education to understand all this push and pull...I also have a hard time seeing now in a single coil of wire how something can be pulling and pushing at the same time half way through the coil of wire.

It is just another way to describe increasing potential or decreasing potential given a chosen direction.

Contrary to what some posters think, there is no universal law saying which direction is the "right" direction. They are confusing polarity with direction. Polarity and direction are related, but they are not the same thing.

 

[jwelectric]

Contrary to what some posters think, there is no universal law saying which direction is the "right" direction. They are confusing polarity with direction. Polarity and direction are related, but they are not the same thing.

But does not the polarity control the direction? Choose which flow you want, electron or conventional, does the polarity not control the direction in which the electrons flow?

 

[Lady Engineer]

Darn it ma'am, get back here and join in. :happyyes:

PS. I told you it was just starting 200 posts ago.

LOL, Jumper! Ma'am makes me sound old. I'm only 35. LOL

Anyway, this should be on a talk show!

Jerry Springer: You say that a center tap on a single phase transformer has a 180 degree phase shift

Forum poster B: Yes, but I'm not being heard, Jerry. That's why I'm on this show. I need to tell everyone the truth, including Forum poster A.

Jerry Springer: Ok, well are you ready? Please welcome to the stage, Forum poster A

Forum poster A: Hi, Jerry...why am I here?

Jerry Springer: You're here because Forum poster B has something he needs to say....

Ok, you fill in the blanks!

 

[mivey]

Anyway, this should be on a talk show!
...
Ok, you fill in the blanks!

Now that was funny. :lol:

 

[weressl]

Well now I must not have enough education to understand all this push and pull.

I was under the impression that there were two different theories of how electrons moved around a circuit and they were as follows, Electron flow where electrons move from negative to positive and the conventional flow where electrons flow from positive to negative.

What I have not learned as yet is that anything is pushing or pulling anything. The way is see it is the electrons are moving from one potential to the other.

I also have a hard time seeing now in a single coil of wire how something can be pulling and pushing at the same time half way through the coil of wire. Take away the induced counter voltage and look at the wire as one straight piece of wire how can the electrons be pushed half way through then all of a sudden the electrons start being pulled?

Maybe I just figured it out. The first half the electrons are doing the electron flow thing and the second half they are doing the conventional flow thing. Yea I can see it clearly now.

To me the easiest analogue is liquid(water) in pipe. Flow is the Current, Pressure is Voltage and resistance is, well: resistance. DC is a continuous, unidirectional flow with steady pressure, and AC is a rising/falling/reversing pressure with flow behavior following the pressure.

 

[Besoeker]

You drew a nodal diagram for your source, but you don't know what a nodal diagram is. I do not have the patience to play games with someone pretending to be something they are not. If you had not come back with a smart alec answer, I would have just let it go, and your guise would not have been revealed.

In post #433, you claimed
"that your circuit, as drawn, is wrong."
Please post what YOU think is a correct version.
Without dancing around the topic.
And I'm still waiting.

 

[Besoeker]

But does not the polarity control the direction? Choose which flow you want, electron or conventional, does the polarity not control the direction in which the electrons flow?

AC
It's AC into and out of the transformer. The electrons don't flow anywhere. The just wiggle back and forth a tiny bit.
Thought you might have known that.

 

[jwelectric]

AC
It's AC into and out of the transformer. The electrons don't flow anywhere. The just wiggle back and forth a tiny bit.
Thought you might have known that.

If I understand what that has been posted in this thread the reason why they ?wiggle back and forth a tiny bit? is due to the speed at which the polarity changes. During the positive side of the sine wave all the electrons are aligned a certain way and then during the negative portion the electrons reverse or in other words they align according to the polarity of the sine wave or flow according to the polarity. Is this not correct?

 

[charlie b]

I have stayed out of this discussion, at least since the last time I tried (unsuccessfully) to bring it back to the original topic. But now I see comments of a personal nature starting to come into the discussion. :thumbsdown: That stops immediately, or the thread gets not only closed, but moved into an area that is not accessible to the general membership. Play nice, or go away!

That said, I am hoping someone can give me a good reason not to close this thread anyway. :happyyes: It has long since failed to give any useful information to the person who started this thread, with my use of the word ?useful? being meant in the context of ?relevant to the original question.?

Without making any attempt to judge any post on its technical merits, I sincerely believe that this entire ?side discussion? boils down to an argument along the lines of, ?The grass is green. No you are wrong, the sky is blue.? I think it best to keep in mind that in the context of electrical theory, anything we draw on paper, anything we describe with words, any mathematical treatment, anything we display on oscilloscopes, anything we use computers to model, all of these things are mere representations of physical phenomena. The phenomena exist as they are, and all we can do is attempt to understand, describe, and make use of them.

But in the end, it does not matter so much how we choose to describe them. For example, I can say two sine waves are 180 degrees out of phase with each other, or I can say they occur simultaneously and reach their oppositely-signed peaks at the same moment, and it does not matter which of these I choose to say. So long as we take care in the choice of reference points, choice of positive and negative signs for voltage measurements, choice of positive and negative directions of current flows, and other related choices, then two seemingly different descriptions can both be accurate descriptions.

And yes I know that electrons just wiggle back and forth a tiny bit, but I am still going to describe them as flowing along a wire at nearly the speed of light, because I find that a useful mental model of a physical phenomenon, and that model helps me build circuits that do practical work.

 

[Besoeker]

If I understand what that has been posted in this thread the reason why they ?wiggle back and forth a tiny bit? is due to the speed at which the polarity changes. During the positive side of the sine wave all the electrons are aligned a certain way and then during the negative portion the electrons reverse or in other words they align according to the polarity of the sine wave or flow according to the polarity. Is this not correct?

Moving off topic further...
Coulombs. C
One Amp for one second.
Copper has a huge number of "free" electrons. That makes it a good conductor.
Each electron has a very small charge but, because of their huge numbers, a small movement of them produces appreciable current.
I did a few calcs, probably some years ago, on this forum.
Take a piece of 2.5mm^2 conductor (somewhere around 14AWG) with 10A.
The speed is about 0.3mm per second. Or about 1/100 of an inch. A half cycle for you is 1/120 seconds.
I'm sure that you can get from this that the distance is quite tiny.

 

[Besoeker]

I have stayed out of this discussion, at least since the last time I tried (unsuccessfully) to bring it back to the original topic. But now I see comments of a personal nature starting to come into the discussion.

You have a point.
When my grasp of the English language is being called in question. And my professional status denigrated and derided. That's personal, uncalled for, and without any basis.
Perhaps that's the kind of thing what you need to address.