EEG_EM_New_Technique_TRANSVERSE_FLUX (TF) (Provisional Patent Applied for)

[solarlab]

A question arose when considering the "Loop Coil" of the EE_TFG. This paper does shed
some light on the subject.

energies article:  Energies 2021, 14, 755. https://doi.org/10.3390/en14030755
https://www.mdpi.com/journal/energies

Improvement of Transverse-Flux Machine Characteristics by
Finding an Optimal Air-Gap Diameter and Coil Cross-Section
at the Given Magneto-Motive Force of the PMs

Partial extract from the article:

"3.2. Varying Coil Dimensions for Improving the Machine's Characteristics
At the next stage of this study, outer and inner TFM models with the air-gap radius
Rδ, at which the lowest value of cogging torque is reached, are investigated. In this study,
the influence of the winding (coil) dimensions on the stiffness of the external characteristics
(terminal voltage) was determined. When examining TFMs with both an inner and an 
outer rotor, the height of the winding was varied. The winding parameters of the outer and
inner rotor TFMs are enclosed in Table 3. This table shows the winding configuration of for
three values of their height: b = 20, 10, 4 mm. For example, the slot section for b = 20 mm
and b = 4 mm, differ by a factor of 5 (520/104 = 5). Having the same number of turns,
(W = 220) and the same filling factor (k = 0.5) the rated current of these windings also
differs by 5 (5.91/1.18 = 5).

Table 3. Winding parameters of the TFM with an outer and inner rotor.
Parameter b = 20 b = 10 b = 4
Height of the coil—b, mm 20 10 4
Width of the coil—h, mm 26 26 26
Filling coefficient—k 0.5 0.5 0.5
Coil cross-section—Scoil, mm2 520 260 104
Cooper cross-section—Scu, mm2 260 130 52
Current density—Jn, A/mm2 5 5 5
Number of turns, N 220 220 220
Conductor cross-section—Swire, mm2 1.18 0.59 0.24
Rated current In, A 5.91 2.95 1.18

The 3D FEM models of the single-phase TFM with an outer and inner rotor with
various coil heights are shown in Figure 10a,b. In the first row, the cross-section of the
coils is Scoil = b × h = 20 × 26 = 520 mm2. These are the dimensions of the winding of the
original model, previously shown in Figures 1 and 6. The physical model of the original
coil used in the TFM prototype (Figure 3b) is shown in Figure 11. The second row contains
the models with the cross-section two times smaller than the original one: Scoil = b × h = 10
× 26 = 260 mm2. And, finally, the third row contains models in which the cross-section
of the coil is five times smaller than that of the original model: Scoil = b × h = 4 × 26 =
104 mm2."

   

"The above characteristics show that to ensure an acceptable generator performance
at a rated current, it is necessary to reduce the cross section of the generator winding.

Therefore, increasing the cross-section of the coil in TFMs does not always mean increasing
of its output power. This is explained as follows: a winding with a large cross-section has
a magneto-motive force comparable to that of the PMs. Consequently, an increase in the
cross-section of the machine winding is possible to a limited value, after which the TFM
characteristics significantly deteriorate."

In the EE_TFG case; the "PMs" are, in fact, "Electromagnets."

SL

[kampen]

Dear Solarlab,

I am in the process of ordering Laminated Coils.
One more thing need to know, please advise about the core field orientation direction.
Is it in color BLUE or GREEN direction?

[solarlab]

Ooops!

Think I found the problem...

Oh well, no harm done - it's only wire and a "too small" dummy load.
Ahhh - the sweet aroma of a frying device just before the flash    @^&#$*#

And quite a suprise from such a cute little tiny device - who would'a thought?

The Lesson, after the fact: Simulate "twice" - Test "once!"
Just having a bit of scarry Fun...

SL

[Red squiggly line at zero is the 1A 50kHz input pulse from the H-bridge]

[solarlab]

Dear Solarlab,

I am in the process of ordering Laminated Coils.
One more thing need to know, please advise about the core field orientation direction.
Is it in color BLUE or GREEN direction?

Kind-of got out of sync here a bit - a lot going on, and between the two forums, easy for me to get lost...

Hi Kampen,

Not sure what you mean by "Laminated Coils." The laminations are the 1/2 Pole pieces,
and the Coils are wound on the longer end of the 1/2 Poles, as shown.

The generated magnetic fields are primarily in both directions (blue and green in your
diagram), but, as you've likely observed, they appear in all directions (6 degree FOV).

The Laminations are stacked going "into-the-page (from your diagram); there should be
a diagram of the lamination direction that was posted a while back.

With respect to the coils - they are wound as "North" on one side and "South" on the
opposite side of a single Pole configuration (the polarities alternate when wound and
wired correctly as the H-bridge reverses the applied current direction).

You might find something that will help in the Maxwell.pdf found in your Student version at
"Program Files/AnsysEM/Ansys Ttudent/v232/Win64/Help Maxwell -Maxwell.pdf"
Search "lamination" - under "lamination modeling," "Stack Direction." The direction depends
on the Material Coordinate System type as shown in the chart:
=> V(1) is X, V(2) is Y, and V(3) is Z. Depends on what you used for material coordinate;
usually it's the Global CS.

Hope this was a bit of help; but don't jump into fabrication too quicky - make sure you
understand how the system works, in detail, first!

Good Luck... Will be busy for a while designing and testing an automated - high speed-
"square coil" winder. Twenty coils per device adds up quickly and is hard on the fingers!

SL

Unfortunately I "Fried" the first pass test before having a chane to analyze it - just had to
"See what she could do!"  Wrong - dumb thing is I did the same thing with the initial
"LinGen."  Anyway, we'll get there - hopefully to a POC, that is... Looking forward to an
independant evaluation, or two, from these forums.

[solarlab]

Splitting the Workload - to allow Looking into an Important Fundamental

A recent discussion with a Colleague stirred a series of questions relating to the Lorentz Force
with respect to some brief observations prior to the EE_TFG meltdown.

It would be significant if a postulation is developed to explain this occurance.

My Collegue's knowledge and experience suggested that, briefly, "the Lorentz Force is
proportional to to the square of the magnetic field" - in other words - the increase is
not linear. He showed the phenomena mathematically (his speciality). 
 * This is in addition to the B-H Curve of the material used. *

Anyway, to keep the story short, I'm going to look into this in much more detail.

In the mean time; the EE_TFG M19 Testing and Analysis will be conducted by one of
my very capable peers under minimal guidance. The "Test Plan" is somewhat straight
forward but very time consuming (lots of various current, winding, and loop variations
to be considered).

It's extremely important, at this phase, that the mechanism be understood, as much
as possible. Limited work constraints mean not everything can be completed in any
reasonable time frame by only one person.

The basic concept has already been presented so it should not have any real impact.

SL