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enter image description here Imagine simple 2 pole 3 phase induction motor, is there a mandatory pattern for the stator windings to creat a rotating magnetic field? Why must the angle between the coils be 120 mechanical degrees to create a rotating magnetic field? why can't I just put the coils in the stator in the order : aa'bb'cc' (each coil in 2 adjacent slots) ? and for 4 poles or more what is the rule?

I understand the math but is there anyway to imagine the whole process in my head? and the last question : How to consider a set of coils as a pole? like in the picture, why did he put the north pole and the south pole there and not vertical for example?

I am sorry if i'm not clear but these things are very confusing..

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The diagram is drawn as it is for convenience and simplicity. The orientation of the north and south poles are given for a specific moment in time. You must carefully study the written description and any other diagrams that are included where you found the diagram. Once you clearly understand the basic process as it is described, you can move on to more detailed presentations that describe actual winding schemes for motors with 2 and more poles. It may help to find the basic presentation presented in different ways. Other presentations are likely to be similar, but there may be enough difference to add to your understanding.

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  • \$\begingroup\$ ok. here is a simple question that may the answer clarifies something for me : What happens if we exchanges the positions of b' and b with each other? would that configuration create a rotating field? \$\endgroup\$
    – iMohaned
    Oct 2, 2016 at 15:50
  • \$\begingroup\$ I believe that reversing one winding would create an imbalance that would result in the magnetic flux that does not remain constant as it rotates. I will see if I can illustrate that a little later. \$\endgroup\$
    – user80875
    Oct 2, 2016 at 16:16
  • \$\begingroup\$ sir , I have drawn the vectors that results from something like that (pattern : abca'b'c') over equal intervals of 3 phase current supply and the vector of the total magnetic field was like that : i.imgur.com/l9rFgTJ.png does that meen that the field rotates with non-uniform speed? \$\endgroup\$
    – iMohaned
    Oct 2, 2016 at 18:30
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    \$\begingroup\$ I have drawn similar vectors i64.tinypic.com/20f7qzd.jpg It appears that the speed is not uniform and the direction reverses momentarily during the course of one revolution. The amplitude varies also. The net direction seems to be the reverse of the direction for the original connection. \$\endgroup\$
    – user80875
    Oct 2, 2016 at 20:14

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