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All the theory about AC generators and motors is wrong!  


Mitko Gorgiev
Member Admin
Joined: 3 years ago
Posts: 42
25/07/2021 10:45 am  

Does this sound shocking to you? Yes, it sounds also shocking to me, but I wouldn’t have written it if I am not sure what I am talking about.
Of course, you may say: 150 years of generators and motors, thousands of great minds and engineers working on the field (Siemens,
 Dolivo-Dobrovolsky, Ferraris, Tesla, etc.etc.), all works perfectly well, and now some fool shows up and says it is all wrong.

You can call me all kinds of names, but it won’t change the truth. And the truth is on my side.

How did the greatest nonsense about the explanation of the working principle of electric generators and motors actually come about? I was thinking quite a lot about it and this is what I have come up with.
In all generators and motors there is one thing which is rotating and another thing which is stationary. An invisible interaction between these two things is thereby going on (figure below).

Now, one intuitively concludes that the force of interaction between the two things is the strongest at the moment when they are exactly opposite to each other as shown in the figure (b) above.

And look now: one considers this intuitive conclusion confirmed by something which is called “Faraday’s law of induction”. Please look at the most exploited figure when the Faraday’s law is discussed:

There are also two things here, one rotating and one stationary. The rotating thing is a wire loop, while the stationary thing is a magnet. According to the Faraday’s law (footnote 1), the magnitude of the induced current is the greatest when the loop is in the vertical position, that is, when the two sides of the loop where the current is actually induced (marked with small “L”) are nearest the magnet. Why? Because the rate of change of the so-called magnetic flux through the loop is the greatest when the loop is in the vertical position.

(footnote 1) Faraday’s law says that E=dΦ/dt; the minus sign before “dΦ/dt” I have left out because it is absolutely not important when one discusses the magnitude of the induced current.


But neither in the former nor in the latter picture is the induced current maximal at those moments. Quite the contrary! In both cases at those moments the electric current is zero and thus the magnetic interaction also.

Do you want a proof that the Faraday’s law is wrong and therefore its place is in the garbage of the history? I will give you the simplest proof you can imagine.
Look please at the figures below:

A straight conductor is moving vertically toward the exact middle of a magnet (figure a). No current is induced in this conductor.
In the second variant the conductor is shifted a little to the right and is moving again vertically towards the magnet. A current is induced in it which flows away from us (figure b).
In the third variant the conductor is shifted a little to the left and is moving vertically towards the magnet again. A current is induced in it which flows towards us (figure c).

In the figures below are shown three variants of a wire moving through a magnetic field. No matter how the wire is moving through the field, whenever it crosses the middle line the induced current falls to zero.

So, when the rotating loop is in the vertical position, the two sides where the current is induced cross the middle line. Therefore, at that moment the current drops to zero. The Faraday’s law predicts maximum current at that moment. NONSENSE!

As a consequence of this delusion there are also others: the so-called “rotating magnetic field” and “magnetic locking”.
The latter term is such a great nonsense that it is actually a pure stupidity. I don’t write this to offend anybody, but to incite you to begin to think. ( Why it is a stupidity I have explained 
here and here).

The first term is not a nonsense per se, but it is also very misleading. Please watch this video about an induction motor:

Is this an AC induction motor? - Yes, it is.
Is it turning? - Yes, it is turning.
Is there a rotating magnetic field that acts on the aluminum disk? - 
No, there is not.

Watch now please how this man explains the rotating magnetic field:

He takes two-phase AC and then applies it to two double coils at 90 degrees distance.
I have never seen such a “wonderful” instance of cherry-picking.

I would ask him how he would apply the concept presented in the video to these three coils:

P.S. If you want really true explanations about the principle of generators and motors, see these articles:

What is the principle of 3 phase induction motor?

Some widespread misconceptions about the electric motors!

Is the Wikipedia’s explanation of the working principle of an induction motor actually a nonsense?

Is the explanation of the working principle of synchronous generators and motors true?

Is Faraday's law of induction true?

What is Faraday's law of electromagnetic induction?

Will touching a neutral wire render an electric shock? Why?

How does a synchronous motor sense that the mechanical load is increasing?