Relation Between Electric Frequency and magnetic field rotation speed in a motor

[Chacabucogod]

Hi!
I understand that if you have a stator with a a three phase electric signal going into it, both the frqyency and angular velocity of the magnetic field and the electric entry will be the same. Now when you feed it with 2 groups of three phases electric signals you get four poles, or at least that is what the book says. Why does that happen. Why does one pole only go half the way and the other one the other half. I can't quite grasp that idea.

Thank you

 

[gkam44]

Chaca, good question. But each of the three phases is in its own winding. The windings are 120 degrees apart physically (rotationally), too. It is not one winding. I have some stuff I used to teach around here somewhere, if you want help in visualization.

 

[Chacabucogod]

That'd helpful! Thankyou

 

[gkam44]

On short notice, I just looked up "three phase windings" and found some pics. http://www.google.com/url?sa=i&rct=...PV3hQaPUk-5Yzlvnh-IclTkg&ust=1414530506784639

One pic shows how the physical windings are put in the stators, and another shows how the three phases line up 120 degrees apart electrically.