Alternative motor windings and drive schemes

[Clugh]

Investigation of Electromagnetic Losses Considering Current Harmonics in High-Speed Permanent Magnet Synchronous Motor
MDPI energies:

In the peer reviewed research what they found is:

When sinusoidal and harmonic currents were applied to the HPMSM, the DC copper losses remained the same in both cases. However, the AC copper losses increased significantly under PWM excitation due to the presence of high-order current harmonics. At low operating speeds, the difference in core losses between sinusoidal and harmonic current operation was relatively small, at approximately 11%. As motor speed increased, however, the core losses associated with PWM current became substantially higher, reaching a 30% increase compared to sinusoidal operation. Furthermore, rotor eddy current losses were particularly affected by the PWM current; across all operating points, the rotor eddy current loss increased by approximately 70% compared to the losses observed under sinusoidal current excitation.

You cant forget the rotor as part of the iron losses and Dr Okon knows all about it as he has had returned plenty of motor where the magnets were permanently damaged. That's why magnovol slot wedges to protect them can broaden the efficiency band significantly.

[Clugh]

They are wrong to claim that everyone can wind the machines. If that were true, why have Dr. Okon and the so-called superior mind of Audiosmith only produced 1- and 2-layer machines in the last 20 years, with no wye-delta hybrids and no 3- or 4-layer machines? These are the cleanest-running FSCW machines on factory stators. They stick to outdated windings and keep creating silly threads to justify to pilots why they haven’t offered any new winding designs in over 20 years, accepting seasonal failures in flight and countless reworks. They refuse to wind modern designs because it would expose that they aren’t leading anything with antiquated windings that “anyone” can supposedly do.

It’s incredibly difficult for someone to explain how it works when they’ve never wound and shown a functioning example. The medical doctor who winds for a hobby has plenty to say to electrical engineering doctors who validated this years ago. To this day, they haven’t produced a working hybrid or anything beyond a 2-layer wind, since their basic Kv calculations don’t align with these designs. Some of these windings can halve AC iron rotor and PM losses, with winding and power factors surpassing the 2-layer machines. The routing and termination are too advanced for the so-called winding “guru” in Gotha. I wound my first hybrid scorpion years ago.

Since they thrive in Germans only sites and Germans only conversations this is clearly a Germans only problem for the goofy forum. The real German EE's and GURUS at the University of Bundeswehr in Munich Germany are fully aware or these advanced winds and are the ones that developed many of them. That's how from reality the Dr is. These are the facts and the only reason id report new winding tech into a forum.

I've even left a video numerous times that show idle currents never achieved by a conventional 1 or 2 layer. They opened numerous threads on the subject matter that never produced a working example and they fall right to the bottom. They can only blame themselves because I sent several people there the winding diagrams and they never produced a thing that works.


Even when It comes to maximum copper fill a serially wound coil is truly not the way.😳

Same turn same direction windings like a servo motor maximizes fill. Additionally it is easier to wind.

[Clugh]

Scorpions Hong Kong 5020

Im not going to waste my time dragging a hard head horse to water but semi magnetic slot wedges is one way to get more out of the rotor and magnets.

[Clugh]

Hallo Ralph, ich habe gelesen, was Sebastian schreibt – ich habe keine Ahnung, wovon er da redet. Ein Pyro 600 liefert weit über 1000 Watt; da liegt er völlig daneben. Ich kann dir nicht viel über ihn sagen, außer dass er in Wirklichkeit gar keine Wicklungen vornimmt. Es scheint, als würde er sich heutzutage darauf beschränken, nur noch zu provozieren. Ich halte nicht viel von ihm; ich habe ihm sogar selbst die Wickelschemata geschickt, aber von ihm sieht man immer nur nackte Statoren. Er hat außerdem einen völlig falschen Bericht über Stern- und Dreieckschaltungen veröffentlicht – mehr als heiße Luft hat er hinter seiner Tastatur noch nie produziert. Viel Erfolg dabei, 11 Windungen eines 1,18-mm-Drahts dort unterzubringen – der Kv-Wert ist für meine Piloten jedenfalls absolut unbrauchbar. In ihren Fluggeräten wird der Motor sehr zahm laufen; bei hohen Drehzahlen macht dieser „Draht“ ohnehin keinen großen Unterschied beim Wirkungsgrad. Der Motor sitzt in einem Getriebe – er kann also, anders als bei einem Direktantrieb, frei drehen. Ich verstehe, worauf du hinauswillst – das ist schon ziemlich amüsant. Ich hoffe, die Lektionen haben dir gefallen.

The motors peak around 4000 watts @ 10s lipo. But motor and drive weight are also very important to them.

[Clugh]

For pilots in North America, there’s no 1.18 mm bare wire available. That size is larger than 17 AWG in our standards, so 11 turns will be interesting to see under the hammers, and not positioned right in the middle of the slot opening near the tooth tips where leakage occurs, resulting in elevated AC losses in the wire. High power density is great, but sometimes it makes more sense to choose a larger machine for more power, especially when pushing them to the limits of their performance.


Thanks,
Hubert

[Clugh]

Die 8 Windungen – im Vergleich zu den vorgeschlagenen 11 – könnten für einen 14-poligen Motor sinnvoll sein. 😏

Gute Nacht...
Hubert

[Clugh]

The Md's theory has some problems.....

If > 400 kmh is the only thing that saves the motor from burning that doesn't explain the fires you've seen in the speed planes that fly that fast. 🙈And then that STATEMENT also means planes less than 400 km/h aren't protected? The truth its what the chart show is motors asked to do more than what they truly can. The way you avoid fires is building larger motors that can comfortably take the loads! And not depending on air rushing by. 😏

Then the entire reason you use thermally conductive potting and not UHU or nothing at all is to keep the working resistance of the wires lower. This has also been proven empirically in North America with F3A motors with it that run an average of 350-850 mah less than motors without it in a P25 flight program.

The motors run cooler and they both see the same amount of inrush rushing air which is probably very little under the hood of F3A aircraft.

If a motor is overloaded it will certainly burn up. It doesn't matter who winds it.

Thermally conductive VIP has already been proven as effective by IEEE long ago and people like Dr Hendesrshot and IEEE fellow who offers the service. Powercroco is not a member. He should submit his unpublished non peer reviewed theories on the closed forum to the body and see if it earns a Hubertus pos DOC grant.

[Clugh]

[Clugh]

[Clugh]

The theory doesn't hold any weight empirically because there is this...... The one pilot he mentions saves his engines buy using thermal protection with the YGE. Everyone that by passes it ends up burnt. That's what all the various repairs of speed grill motors is all about. he claimed the YGE limiting was the limit to the power on the motors so they bypassed them and the 1000 dollar motors and 600.00 inverters lit up like a Christmas tree.

The engineers at YGE totally rejected his theory and agree the motor are a limit to themselves and their inverters will protect itself from an overloaded motor when the safe guards are implimented
The Builder in GOTHA can make his claims about air rushing pass the and motor case but empirically I think the EE's and YGE know what they are talking about. He walks right around these results all the time. The question is will you? Its a costly decision so make sure unless you have plenty of money to burn.

TTYL
Hubert

[Clugh]

Brushless motor tuning through copper fill level optimization without theoretical babble!

A thread title like this really underscores the ignorance of the editors, especially when you consider the millions of dollars spent on R&D and empirical testing by at least 70 universities worldwide, showing minimal deviations from established theories in controlled labs—not on a rc plane full of unaccounted-for variables. Not to mention the formal education and patents for devices based on these theories, many of which are used commercially every day.

The man has rewritten the books and proven them all wrong rewinding a few drone motors and unapproved wooden test stands.... lets see who adopts them in the "real world"

Certainly the academic motor EXPERTS don't have the empirics or resources to trump that...

[Clugh]

"You can chase much more current at partial load, generating more torque." ~Sebastian Kunzke~

Torque is roughly proportional to q-axis current in FOC control.

However:

• More current always generates more copper loss.
• Efficiency does not necessarily improve.
• "Partial load" alone doesn't mean additional current is beneficial.

FOC allows torque production to be controlled more effectively and can maximize available torque within motor limits.

"That's why the Halbach array doesn't help so much." ~Sebastian Kunzke~

A Halbach array:

• Concentrates magnetic flux on one side.
• Reduces flux on the opposite side.
• Can increase air-gap flux density.

But if the stator is already saturated:

• Additional concentrated flux may provide little benefit.
• The iron cannot effectively utilize the increased field.

In that specific situation, the author's conclusion is reasonable.

However:

• Halbach arrays can still improve efficiency.
• They can reduce rotor losses.
• They can improve flux distribution.

So saying they "don't help much" is highly dependent on motor design.

[Clugh]

" Above all, the inductive resistance limits the current. "~Christian Lucas~"

At low speed

Not really. Current is mostly limited by:

• winding resistance
• battery voltage
• ESC current limits

Inductance has relatively little influence.

At high speed

Absolutely true.
As electrical frequency rises:

• Low speed → resistance dominates.
• High speed → inductance becomes increasingly important.

[Clugh]

Hi Christian,
I largely agree. At high speed, current is limited by the available voltage budget:

V=EbackEMF+IR+L(dt/dI)

Back-EMF is usually the primary speed-limiting factor, while winding inductance and saturation increasingly restrict current buildup as electrical frequency rises. Once the stator teeth approach saturation, inductance drops, leakage flux increases, and additional current produces diminishing torque gains. This is why simple Kv, resistance, or efficiency calculators often miss what is really happening. Short-circuit and loaded measurements provide much better insight into inductance, saturation behavior, and the true current limits of the machine. Field weakening can extend the speed range by reducing effective air-gap flux and back-EMF, but it does not eliminate the underlying limitations imposed by inductance, saturation, thermal effects, and the available DC bus voltage. In the end, measurement is usually more valuable than relying solely on simplified models.