4 Pole Induction Motor Working Principle

[BlackMelon]

Hello,

I am studying the working principle of an induction motor. The attachment below (link) is a portion from Stephen J. Chapman's textbook (page 160-169). He proved the theory of the rotating magnetic field so well for a 2-pole induction motor from 160 to 164. However, on page 166, the author proposed a 4-pole motor but did not provide the similar proof. I would like to know how this configuration forms a rotating magnetic field and makes the rotor (squirrel cage) rotate. Do you guys have any good papers for this?

https://www.mediafire.com/file/86a7...-2bh471C15I5A5Gi_YZx77Vy9g6jgxUTzcZuZAwiHQijI

Thank You
BlackMelon

 

[artis]

@BlackMelon the number of poles is just that aka the number of poles, the underlying physics of how the motor works doesn't change. The only thing that changes is the torque and RPM characteristic of the motor but the physics is the same, you still have a current that changes with time and drags the rotor along, only with more poles each set of coils drags the rotor a smaller distance.

Having less coil pairs/pole pairs means that each coil is located more degrees apart and each cycle drags the rotor for a longer distance.
This is why for a given fixed frequency fast RPM motors usually have less poles , as a consequence they also have less torque