Motor Basic Clarification

[Vihaan]

It is really tough for me to understand the basics of motor, i had one bldc motor which i opened below is the image

The stator (slots where the coils are wound?) i could rotate with hand so here stator is moving, the rotor is having 8 permanent magnets so it is 4 pole motor with alternating North and South pole. My initial doubt was if i take the magnet1 for example if it is North then its south pole is unused? Is it possible to say which is North and which is south? Why do we say one North and South pole is 360 electrical degrees?

 

[E-HP]

It is really tough for me to understand the basics of motor, i had one bldc motor which i opened below is the image
View attachment 377438
The stator (slots where the coils are wound?) i could rotate with hand so here stator is moving, the rotor is having 8 permanent magnets so it is 4 pole motor with alternating North and South pole. My initial doubt was if i take the magnet1 for example if it is North then its south pole is unused? Is it possible to say which is North and which is south? Why do we say one North and South pole is 360 electrical degrees?

I'm not clear on the questions, but this article has some simple versions of a BLDC motor and the magnet arrangement. Maybe there's something there that will help clarify things.

https://www.monolithicpower.com/media/document/Brushless_DC_Motor_Fundamentals.pdf

 

[lnanek]

Running the current through an electromagnet in the opposite direction creates a magnet with the opposite pole compared to usual. Or, I suppose, just winding it with a corkscrew going the other direction. One you can have a controller do with MOSFETs, though, and the other you can only do in the factory when creating the motor. So for the electromagnet portion, there isn't a wasted pole as the controller can make it whatever pole it wants.

There isn't really any reason one is "north" and one is "south" or that the right hand rule works either, it's all just convention. A lot of electronics is like that. We even got the direction of electrons vs. electrical current wrong in the early days and it stuck.

 

[stancecoke]

It's just a matter of definition.
To see what is where, just put a constant angle, a constant ud and uq=0 to your inverse Park and look to which position the rotor moves

 

[fill]

The RC world has been hands on and screwdriver deep with bldc motors for a long time and can be a great source of primer material at all levels.