Hi Vidar.

I cannot tell if your simulation was any good or not. I don't know how to operate Femm.

And I don't know how you could simulate any torque without the stator magnets in place.
When the rotor magnets are out of electro magnet position you have zero stall torque.
Your simulations must calculate stall torque in various positions. when you do this you'll
see that using stator magnets will create torque to twist the rotor. Without the stator no twist.

You could use the original simulation file posted here to see if you get some other output.
ACP got 50.85Nm torque in his simulation using grade N37. My calculations is based on N45.
http://www.overunity.com/index.php/topic,3456.msg54963.html#msg54963

It's not the first time Femm have been flawed in situations it haven't been programed to cope.

Yes, but I haven't drawn the electro magnets in these drawings. I just wanted to see the stall torque of the rotor.
You can look at the PDF how they are designed and then insert them yourselves before simulating.
The blue area is just the winding. You don't need to draw that to perform the simulation.

Femm can't simulate this properly, look at the reszlts of the simulation, all the flux is concentrated around the ends of the spiral. Because the program is 2d it can't simulate the flux lines flowing under and over the spiral which is what happens in real life.
The flux lines have to complete a closed circuit because the program is 2d the only way the magnets can complete the cycle is by looping around each end of the spiral.
I allready tried some practical experiments, and from what I can see, the spiral behaves quite differenty than that shown by Femm, It has some torque around the whole spiral as Honk predicted and not just at the extreme ends as shown by the Femm simulations.

Magnetic fields interact only in the same plane. Two magnetic fields that are crossed by 90 degrees does nor repel or attract, so 3D is not necessary. However I understand your concern regarding FEMM, but as far as I know, the magnet arrays, even if they are bent like a half "circle", it will behave as a long straight magnet to a smaller magnet. A smaller magnet will allways try to find the middle of the long magnet - an optimum resting point. As you can see in FEMM, there are few or no magnetic lines in the middle of each statormagnet array which in fact (as far as I can see) is simulating exactly that. Maybe I'm totally wrong - I hope so. Maybe Honk will succeed with his project

Vidar

Magnetic fields interact only in the same plane. Two magnetic fields that are crossed by 90 degrees does nor repel or attract, so 3D is not necessary. However I understand your concern regarding FEMM, but as far as I know, the magnet arrays, even if they are bent like a half "circle", it will behave as a long straight magnet to a smaller magnet. A smaller magnet will allways try to find the middle of the long magnet - an optimum resting point. As you can see in FEMM, there are few or no magnetic lines in the middle of each statormagnet array which in fact (as far as I can see) is simulating exactly that. Maybe I'm totally wrong - I hope so. Maybe Honk will succeed with his project

Vidar

But magnetic fields in real life are 3d not 2d. The flux lines have to complete a circuit, they have to leave and enter the same magnet. In Femm this is only possible for the middle magnets of the spiral by running around the ends of the spiral and back again, This distance is too far, consequently the fields are negated. In real life however, the magnets in the middle of the spiral can complete their cirduit by looping under and over the spiral which is a much shorter distance than looping around each end of the spiral as in the 2d case. Long lengths of magnets arrays without gaps between aer not acurately modelled in Femm.

Great Saving

By the way, buymagnet.com and ndfeb-magnet.com  seem to be one and the same manufacturing company,  Shenzen Shan, in China. They also produce small motors.

Will they supply the rotor magnets shaped according to the drawing? Are there any news on the laser cutting of the steel parts?

I guess I'm ready to place the orders on the material I need to build the motor.

1) Magnets from China.
2) Laser cut parts from my buddy.
3) Supermalloy for the electro magnets (not yet confirmed price)
4) Various lokal parts, bearings, steel shaft, screws, generator gear.

Sounds great Honk, I really look forward to your updates. Thanks