I continue on my quest to build my own e-bike motor. This is probably the last prototype motor I build before going for the real deal!
.STL files on Printables: https://www.printables.com/model/5499...

Some clarifications and amendments:
*An extra note on the geometry of the stator - The involute stator design also allows the stator to have more effective copper area in it (especially if concentrated windings are used)... I cut that part out from the script because the video was already starting to get pretty long...
*A little definitions mistake also snuck in: Technically every permanent magnet and reluctance motor is a "synchronous motor" (the electrical rotation is in synchronous correspondence with the rotor rotation)... The definition of synchronous in this video differentiates between motors where all generated electromagnet poles are exactly in sync with the magnetic poles of the rotor, rather than not (for example BLDC motors which have more- or less permanent magnets on the rotor than generated electromagnet poles)
*A clarification on how exactly reluctance motors work: I nearly completely gloss over the explanation in the video but generally you can think of it in the following two ways; Reluctance motors work based on magnetic circuits. Because air is poor at "conducting" magnetic fields (it has a high reluctance), then if the rotor is made of material that the magnetic field lines would take preferentially (low reluctance), then the lowest energy/steady state of a magnetic circuit is where this low reluctance material is as aligned to the applied magnetic field as possible. Now, as the electromagnet poles in the motor move (the higher intensity magnetic flux regions move), the magnetic flux lines are no longer properly aligned with the low reluctance material in the rotor. Since this is not the lowest energy state/steady state for the system, then it produces a torque on the rotor to align it back towards the lowest energy state, which is where the reluctance rotor poles are exactly lined up with the electromagnets, thus making the rotor move along with the electromagnet poles.
Another way to think about it would be that since the reluctance rotor is made of materials that have high permeability (permeability is inversely proportional to reluctance) then the material itself becomes a magnet as the magnetic flux passes through it (just like electromagnet cores become magnets). Since the electromagnet pole and the pole generated in the rotor are opposing polarities then they attract, and as a result as the electromagnet pole rotates, it pulls the rotor along. This second way of explaining it is roughly what I tried to quickly convey in the video too, as I believe it to be much easier to understand.

=|Featured Videos|=
   • Electric Motor Winding Types Comparis...  
   • Understanding electric motor Windings!  
   • Understanding electric motor Windings!  

=|Links|=
Back iron flux lines images (and there's lots of good information there):
https://things-in-motion.blogspot.com...

=|Music|=
(0:10-2:51) "Smooth Waters" - SergePavkinMusic
(3:00-5:36) "Documentary" - Coma-Media
(5:38-7:33) "Graze the Roof" - Plants vs. Zombies OST
(7:53-8:53) "Kawaii!" - Bad Snacks
(9:14-10:46) "Bittersweet Waltz" - Sir Cubworth
(11:09-12:34) "Lost in LoHI" - DJ Williams
(13:10-13:57, 14:17-15:22) "Energetic Indie Rock" - Oleksii Kaplunskyi (LesFM)
(15:37-16:28) "Orient" - SefChol

=|Chapters|=
0:00 - Intro & Motivation
0:54 - Axial Flux
1:26 - Synchronous
2:07 - Reluctance
2:46 - Stator design
4:26 - Windings
5:33 - Construction
6:20 - Electromagnet cores & back irons
7:40 - Project rediscovery
8:07 - Sensors
8:49 - First run (failed)
9:35 - Fixing the mistakes
10:44 - "Moderate" success
12:10 - Permanent magnet rotor
12:35 - Success!
13:46 - Measuring max speed & kV
15:22 - Future, Files & Outro