Magnax, new axial flux motor

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Altair   1 kW

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Magnax, new axial flux motor

Post by Altair » May 31 2018 7:05am

Interesting new development here: https://newatlas.com/magnax-axial-flux- ... %20Monitor

[moderator edit to add product name]

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Re: New axial flux motor development

Post by gogo » May 31 2018 7:52am

https://newatlas.com/magnax-axial-flux- ... tor/54821/
Note: there are graphics and videos at the link site (along with adverts I didn't care about).

After nearly a decade in development, Belgian startup Magnax claims it has developed an ultra-high power, lightweight, compact axial flux electric motor with performance figures that blow away everything in the conventional radial flux world. Crucially, it says it's worked out how to manufacture them too.

It might not have the romance of combustion engine tuning, but it seems a bit of a battle is brewing to develop the kinds of high-performance motors that will power the electric cars, motorcycles, aircraft and industrial equipment of the future.

A week ago we wrote about Equipmake's spoke motor design, which allows it to pump out some 9 kilowatts per kilogram with exceptional cooling and continuous power production ability.

To put that kind of power production in perspective, the ludicrously fast 193-horsepower BMW S1000RR superbike of 2011 – a power-to-weight beast that would slay just about anything in the automotive world – has a lightweight motor that makes a puny 2.4 kilowatts per kilogram. So 9 kW/kg is no joke.

Which makes this axial flux, direct drive motor from Belgian company Magnax a real eyebrow-raiser. Magnax claims it makes a peak power no less than 15 kW/kg, with the ability to produce sustained power at around 7.5 kW/kg. To bring that back to the motorcycle example, if you built a Magnax motor that weighed as much as the BMW superbike's engine, you'd have yourself a 603-horse powertrain that could produce bursts of up to 1206 horsepower for short periods before overheating and needing to take it easy for a bit.

Obviously, that's a silly example, but these kinds of ultra-lightweight motors could do significant work towards offsetting the large weight figures of today's heavy lithium battery packs in electric vehicles. And until automotive-grade battery density takes a significant leap forward as it's been promising to for several years now, weight will continue to be a serious issue for e-mobility.

Benefits and drawbacks of Axial Flux Designs

While the vast majority of electric motors currently in circulation are radial flux designs, Magnax claims the key to the high power density it's achieving is the direct drive axial flux design used in all its motors, which uses a stator disc sandwiched between two rotor discs with small air gaps in between. Yokeless axial flux motors, the company claims, have a number of advantages if implemented properly. The flux path is shorter, and the magnets further away from the axis, leading to greater efficiency and leverage around the central axis.

What's more, the axial flux design allows Magnax to waste very little copper on overhanging loops on the windings. Magnax's motors have zero overhang; 100 percent of the windings are active, where the company claims radial flux motors can sometimes have up to 50 percent of their copper inactive, adding extra resistance and causing heat build-up. Magnax uses a rectangular-section copper wire in its windings to give the highest possible density. And the motors are much thinner than radial flux machines, meaning that you can stack them easily to work in parallel.

There are, of course, difficulties when it comes to building axial flux motors – otherwise everyone would be making them. Powerful magnetic forces acting between the rotor and stator discs tend to make it very difficult to keep the air gap between them uniform. If they start to wobble or bend, the discs can start rubbing against one another, leading to bearing damage at best, and rapid, spectacular unscheduled disassembly at worst.

Magnax claims it addresses this in its yokeless axial flux design by having two rotor discs that constantly put equal and opposing forces onto the stator disc. The rotors are connected directly to one another via a shaft ring, so the magnetic forces cancel each other out, and the internal bearing doesn't have to deal with them.

Cooling is key with any high powered electric motor that's expected to do consistent work, and axial flux designs tend to suffer in this regard, since their stator windings are sandwiched between the rotor discs, making it hard to get heat out. Magnax claims its motor designs cool well, as the windings are in direct contact with the outer aluminum casing, allowing decent heat transfer.

It seems to be working. Continuous power figures for the Magnax motor come out at 50 percent of what it can make at its peak, which is pretty decent but not in the realm of the best-cooled radial flux motors. The Equipmake motor, for example, can continuously make nearly 70 percent of its peak power, suggesting superior cooling.

One further challenge comes with manufacturing, as the stator discs can be particularly hard to get right, and even harder to build in an automated high volume process. So when they do get built, they're hand-made and highly expensive as a result. Magnax claims to have cracked this problem too, with a number of "proprietary solutions" that allow it to scale and build these things cost-effectively.

The Magnax motor is highly scalable, ranging in size from 15 centimetres (~6 inches) right up to discs 5.4 metres (~13 feet) in diameter and beyond. They can be slotted in next to one another to run in parallel, and they can run either as direct drive or through a gearbox if you're willing to accept the efficiency losses involved.

Magnax is pitching them at electric cars and motorcycles, aircraft rotors, and as large-diameter, high torque, low RPM solutions for wind power, hydroelectric and wave power generation.
At the end of the day, field testing in the automotive and industrial worlds will be the proof of this pudding, but if this is truly a high-power, long-life, well-cooled, high-efficiency, low-maintenance axial flux motor, Magnax could be poised to make some serious waves.

The company has spent some nine years getting its tech together after a proof of concept was originally built at the University of Ghent in 2009. Now, it claims to have working prototypes and a manufacturing methodology sorted out. With a bit of luck, the rubber will hit the road soon and we can see if this truly is the electric motor of the future.
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spinningmagnets   100 GW

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Re: New axial flux motor development

Post by spinningmagnets » May 31 2018 8:00am

An axial flux should be the first configuration that should be considered when pondering a motor design where size is a concern. It provides the maximum copper and steel-lam density per motor volume.

That being said...in any application where there is a little room to play with, a radial-flux outrunner has a lot of options going for it, especially cost, and torque - per material cost (since all the magnet volume is located at the very perimeter)

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Re: New axial flux motor development

Post by lizardmech » May 31 2018 11:28am

There seems to be an endless stream of startups with axial flux motors but they never have much of a business strategy, they usually release a few demo units then spend the next decade hoping some car company will buy them out or order millions of units. None ever try to target markets where a smaller company could compete like hobby/drone motors and ebikes.

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Re: New axial flux motor development

Post by Voltron » May 31 2018 1:02pm

Possibly the manufacturing difficulties made them too pricy for what's considered the disposable toy industry. I love my ebike of course, but motors like these are going to be in electric aircraft and cars that have needs beyond hobby level performance.

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Re: New axial flux motor development

Post by amberwolf » May 31 2018 6:55pm

Is that the same as this one?

viewtopic.php?f=10&t=93444

If so, maybe someone could put the two threads together so all the info stays together? If not, just ignore me....

Altair   1 kW

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Re: New axial flux motor development

Post by Altair » May 31 2018 8:46pm

Indeed, it's the same motor.
As nothing new has been added here, is it possible to just delete this thread here?
I am the OP, can I do that?

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efMX Trials Electric Freeride   1 MW

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Re: New axial flux motor development

Post by efMX Trials Electric Freeride » May 31 2018 9:26pm

Altair wrote:
May 31 2018 8:46pm
Indeed, it's the same motor.
As nothing new has been added here, is it possible to just delete this thread here?
I am the OP, can I do that?
you can delete your posts but not the responses of others.. next time maybe do at least a quick search before creating new threads;) ..
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i have nothing for sale.. :)

Altair   1 kW

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Re: New axial flux motor development

Post by Altair » Jun 01 2018 5:56am

You're right.
:oops:

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Re: New axial flux motor development

Post by major » Jun 01 2018 10:19am

gogo wrote:
May 31 2018 7:52am
https://newatlas.com/magnax-axial-flux- ... tor/54821/
Note: there are graphics and videos at the link site (along with adverts I didn't care about).

After nearly a decade in development, Belgian startup Magnax claims it has developed an ultra-high power, lightweight, compact axial flux electric motor ...


What's more, the axial flux design allows Magnax to waste very little copper on overhanging loops on the windings. Magnax's motors have zero overhang; 100 percent of the windings are active, ...
Appears to claim zero end turns, which is BS from what I can see from the coil picture.
magnax-axial-flux-motor-7.jpeg
Coil
magnax-axial-flux-motor-7.jpeg (72.13 KiB) Viewed 2734 times
Regards,

major

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Re: New axial flux motor development

Post by billvon » Jun 01 2018 11:15am

major wrote:
Jun 01 2018 10:19am
Appears to claim zero end turns, which is BS from what I can see from the coil picture.
Looks like a solenoidal winding to me. In a solenoidal winding, all the copper contributes to flux. (Wires going to the power supply excepted, of course.)
--bill von

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Re: New axial flux motor development

Post by liveforphysics » Jun 01 2018 1:32pm

End turns always contributed to flux, just the flux the ends generates is on the wrong axis to be making rotational torque, and instead makes a balanced thrust axis force that net cancels.
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Re: New axial flux motor development

Post by major » Jun 01 2018 2:59pm

billvon wrote:
Jun 01 2018 11:15am
major wrote:
Jun 01 2018 10:19am
Appears to claim zero end turns, which is BS from what I can see from the coil picture.
Looks like a solenoidal winding to me. In a solenoidal winding, all the copper contributes to flux. (Wires going to the power supply excepted, of course.)
Hi billvon,

This may be true for a free standing solenoid as shown, but is not the case for the coil when used in the magnetic circuit in the motor. Apply Ampere's Law and see that the end turns contribute thousands of times less flux than the coil sides passing through the magnetic paths and it is a very close approximation to say the end turns contribute nothing.

We had a whole thread on the subject not long ago, so I guess we needn't rehash it. Amberwolf will get upset .

major
Last edited by major on Jun 01 2018 10:34pm, edited 1 time in total.

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Toorbough ULL-Zeveigh   100 MW

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Re: New axial flux motor development

Post by Toorbough ULL-Zeveigh » Jun 01 2018 10:08pm

their white paper iz a reely light shade of pale.
my impression (not enuf info to draw a conclusion);
the square wire iz gud for a couple percent improvement.
liquid cooling fer even more.
no way 2tell how much the flux being axial makes up the difference.

not even a price mentioned. (did i blink & miss it?)
but when it cums2 to price premium, flemish engineering is to german engineering what german engineering iz2 chinese engineering.
lizardmech wrote:
May 31 2018 11:28am
There seems to be an endless stream of startups with axial flux motors but they never have much of a business strategy, they usually release a few demo units then spend the next decade hoping some car company will buy them out or order millions of units. None ever try to target markets where a smaller company could compete like hobby/drone motors and ebikes.
letz me putz it in perspective for you.
axial flux is the betamax of electric motors.
a slight improvement over radial at a much higher price.
i'd happily make use of it if were given 2me but itz so above my pay grade i'll likely never c1.
you precisely put your finger on it.
there's been enuf kix at the kat that if it had anything 2offer we'd have it by now.
spinningmagnets wrote:
May 31 2018 8:00am
An axial flux should be the first configuration that should be considered when pondering a motor design where size is a concern.
the first 2b considered & rejected.
you need to back up this drunken boast with a reel world example.
show me the biggest axial ya got & i'll whip out mine.

http://www.diyelectriccar.com/forums/sh ... 7301256232

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spinningmagnets   100 GW

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Re: New axial flux motor development

Post by spinningmagnets » Jun 02 2018 11:42am

It's true I was drunk when I wrote that, but...when you have a few moments to spare, this might be interesting:

"Lebowski DIY triple-stator dual-rotor axial-flux motor"
viewtopic.php?f=30&t=46476

I't's not the "biggest" axial flux (designed to be 1,000W?), but the design is scale-able for those with the time and inclination. Full disclosure, I have not actually built one, but...I trust Lebowski's posted performance data.

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Re: New axial flux motor development

Post by Vanarian » Jun 08 2018 7:37am

liveforphysics wrote:
Jun 01 2018 1:32pm
End turns always contributed to flux, just the flux the ends generates is on the wrong axis to be making rotational torque, and instead makes a balanced thrust axis force that net cancels.
Thank you for this tip, it means I'm not wasting my time right now trying to go hybrid!
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Re: Magnax, new axial flux motor

Post by zzoing » Oct 06 2018 2:18am

They should send one to Justin so that he can give us some decent efficiency and power and torque ratings for it. I'd say it can have 2x the torque based on the magnet surface area. Whether that means that it captures twice as much as of the magnetic field is another matter. it must be twice as slow too. Magnax claims that their motor is 23 kilos, versus a typical tesla motor which is 35 pounds, perhaps that means we can have 3 kilo motors on ebikes that can run 2kilowatts. one for the future.

Will send the axial motor pages to Xlyte and 9C so that chinese can mass copy them in a miniaturized version.

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