With concentrated three-phase winnings in nine slots, you have built a stator for a three-pole motor, which makes no sense to me. The "14P" motor presumably means "14 pole"... which makes no sense either. How did you pick these configurations, and what are you using as a reference guide to motor design that would lead you to pick those?
Posts by brian_
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It looks like you intended to attach a table, but it's just a link to imgur that doesn't show any relevant image. Where did you get the table? Is there a website with instructions for building motors that you are following?
Motors certainly can work without iron cores, but except in the case of specific designs to work that way, they will generally work poorly. I suspect that most stuff (of any kind, motors or otherwise) shown working in YouTube is either barely working or simply fake, as the maker is more interested in YouTube views than the technology.
Decades ago in a high school shop class we built working brushed DC motors, back before "3D printing" existed (before most people had any kind of computer at home)... and even it that design had an iron strap for a field (stator) core and a bundle of nails for an armature (rotor) core.
Okay, I see what they're doing. Rather than using windings for each phase is pairs mirrored across the motor, they have only a single winding per motor pole pair per phase. The magnetic field paths are terrible, but I don't think anyone building these is concerned with designing an effective motor anyway... they're not the sort of thing you would find in an EV.
The blue motor (9 slots in stator, 6 magnets in rotor) is a 6-pole motor - it has three times as many magnets in the rotor and three times as many winding sections in the stator the simplest 2-pole motor. A normal 3-phase 2-pole motor has six windings:
(ignore the voltages in this example, and note that this example is delta-wired; also note that this is an inner-rotor motor, but the principle is the same as an outer-rotor)
... so a 6-pole motor would have 18 windings (in 18 slots if using a concentrated winding scheme like this).
The motor built according to this more crude design has only three windings for 2 poles
... and so only 9 windings (in 9 slots) for the 6-pole version.
(this one is shown with wye wiring, but it works the same with delta)
So now I understand that the 9-slot 6-magnet motor should work, if driven correctly, although with no iron it will be ineffective and inefficient.
This page gives a decent description of how the three phases must be driven to work, and why it works:
Controlling BLDC Motors
It even uses the minimal winding pattern (without mirrored pairs of windings). Note that it uses the normal 3-phase notation of UVW instead of ABC, but they mean the same thing.
The key to making this work may be that the phases are not just "turned on" in a suitable sequence - they are connected to positive or negative as appropriate to make the current flow the correct direction through the winding for the stage in the energizing pattern - it goes in six steps, not just three - and I don't know if your controller is doing that:
(the green arrows show the current flow and the pink arrow shows the resulting magnetic field)
Obsessive Compulsive Disorder
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