Electric Motor Secrets

[Jetijs]

Schpankme,
# I think I will increase the outer diameter of the stator from 100 to 120mm that is the size of a CD. I need it to be a little bigger because of the shaft and bolt diameter issues. I do not know about the thickness yet, it all depends of the material and cuttng costs. I think the thickness will be 60-100mm, that is 120-200 plates (if I will het them at 0,5mm thickness).
# I do not know if there is any off shelf motor that could be perfectly suitable for this. Steven tried to convert a simple induction motor core, but we do not know the results yet. As you can read in previous posts, such a off shelf induction motor stator core is a real pain to wind. Also the poles could be too close together. Tomorrow I will see what the guys form the motor rewinding company will tell me, maybe they have something that is more suitable
# You are going a mile a minute. I haven't even built one myself yet, so I can not tell you how much the shipping of such items will cost. I haven't even thought about selling these cores. At first we must built and test one motor an see how it performs, that could take some months.

Thanks,
Jetijs

[Schpankme]

simulation of your core

Schpankme,
I did a simple simulation of your core ... Here are the results:

Thanks,
Jetijs

Jetijs,

Looks like were winding the cores on the inside.

New Project Motor

o Have you decided on motor Dimensions?
o Wonder if there's an "Off the Shelf" Motor to use?
o What's your price for shipping me a new motor kit (stator & rotor)?
o This is the perfect time for others to join in.

- Schpankme

[Jetijs]

Schpankme,
I did a simple simulation of your core and it does not look good. I used vizimag for this. Here are the results:



I think that these images speak for themselves
Thanks,
Jetijs

[Schpankme]

Did a quick simulation

Regards,
Steven

Steven,

I'm curious as to what the simulation would show for patterns, if we put the Stator/Coils on the outside. Or would we end up with a Faraday Cage!

Could you produce the simulation for the motor geometry attached?

- Schpankme

[lighty]

@nali2001

Ah, I see how you did it. Clever decision to avoid hassle with coil defs. Thx for the idea.

[nali2001]

Simulation

Well I did not use a 'coil material' so there are no current sources. I just used magnets in the simulation - to simulate the coils.
http://home.planet.nl/~sintt000/Motor.FEM

[Schpankme]

Phase Switching & Rotation

Schpankme,

... the 2 pole rotor under test is pretty quiet
... how you can produce specific attraction cycles with the 3x5 arrangement

Peter

Peter,

Your point is well taken; my thoughts were to create Phase Switching & Rotation of the Rotor to achieve max drive torque.

Regarding Rotor assembly - the rotor made from multiple plates and held with multiple nuts & bolts, looks to be a low tech way of achieving max performance?

- Schpankme

[lighty]

@nali2001

I know it's a bit OT but I presume you made that simulation in FEMM. Could you please share the simulation file? I'm interested in how did you define the current sources.

[nali2001]

Simulation

Did a quick simulation
http://home.planet.nl/~sintt000/Simulation.gif
on that core design and to me it seems just fine.

One thing though since the poles of the stator are somewhat close to each other in this design, extra precautions must be take to insure that the rotor looses as much residual magnetism as possible, before it has reached the next stator finger. If not and the next finger coil is loaded it will cause cemf (back emf) and will draw additional currents under load. Just as any other motor. (which will probably be the biggest problem in my motor due to the solid steel rotor)

Regards,
Steven

[nali2001]

Core

Hi there Schpankme,
Well a two pole rotor is as much in balance as any other design that can be mirrored. Your design is in my opinion problematic to a fair extend. I presume that you will be firing the coils in '3 cycles' well what this does is that the magnetic attraction is not equal that means that the is a somewhat unbalanced attraction on the rotor. Since you (I presume) only energize one coil at a time this will cause vibrations an stresses on the bearing that must not be underestimated. And it is true that a big problem of reluctance motors is the noise. Since there is a deformation of the core it self happening. And it is a know and little resolved problem with these motors.

Plus the back spike recovery besides circuitry also depends on the material. Very fast materials with high permeability are eventually preferable like Hyperco50, Metglas or even Somaloy but that is out of the question now (likely always)

Kind regards,
Steven

[Peter Lindemann]

How Does This Work?

Peter, et al

From your critique, it's understood that the Stator density could disrupt the ability to harvest max energy. My goal is a motor that provides max torque and harvesting.

As an alternative here's the 3x5 (3 pole rotor/5 pole stator). My reason for suggesting this geometry is that it lends itself well to keeping mass center of the rotor; compared with the 2 pole rotor, which 'in my opinion' present issues of harmonics/tunning at sonic and subsonic speeds.

- Schpankme

Schpankme,

You can see and hear on my YouTube clips that the 2 pole rotor under test is pretty quiet, so I don't see a problem with the issues you raise. Also, I don't understand how you can produce specific attraction cycles with the 3x5 arrangement you are currently suggesting.

Peter

[Schpankme]

3 pole rotor/5 pole stator (3x5)

Schpankme,

... The 4 pole rotor mating with the 6 pole stator ... For high torque with no recovery, this design works extremely well.
... for our purposes ... it does not provide space for a "pause" between ... coils going off before the next set of poles are in alignment ...

Peter

Peter, et al

From your critique, it's understood that the Stator density could disrupt the ability to harvest max energy. My goal is a motor that provides max torque and harvesting.

As an alternative here's the 3x5 (3 pole rotor/5 pole stator). My reason for suggesting this geometry is that it lends itself well to keeping mass center of the rotor; compared with the 2 pole rotor, which 'in my opinion' present issues of harmonics/tunning at sonic and subsonic speeds.

- Schpankme

[elias]

Yes

Elias,

You are correct. The other poles are just waiting. If you put an "X" rotor in this stator, the rotor won't know which direction to turn, being attracted back as well as forward. In fact, it wouldn't turn at all. Think it through. You'll see it.

Peter

Yes That'll happen, I was not considering the fact that the stators turn on and off separately, I was not sure about how the magnetic flux behaves on the core.

Thanks

[Peter Lindemann]

Poles Waiting...

Peter,

Wouldn't it be better if Jetijs, used a "+" shaped rotor? I mean wouldn't it add to the mechanical output?

It seems that while one pair of the stators are attracting the rotor, the other pair are just watching.

Elias

Elias,

You are correct. The other poles are just waiting. If you put an "X" rotor in this stator, the rotor won't know which direction to turn, being attracted back as well as forward. In fact, it wouldn't turn at all. Think it through. You'll see it.

Peter

[elias]

A question popped into my mind.

Peter,

Wouldn't it be better if Jetijs, used a "+" shaped rotor? I mean wouldn't it add to the mechanical output?

It seems that while one pair of the stators are attracting the rotor, the other pair are just watching.

Elias