Halbach Axial Flux Motor

[AussieJester]

Courtesy of Miles from Endless Sphere-->

Here's a PDF with some information on the LaunchPoint motor

KiM

 

[safe]

LaunchPoint

...pretty much sums up why I switched projects.

There is snow outside this morning. :chillpill:

 

[Email]

Sounds like a Tesla Turbine in terms of performance. Perhaps a marriage made in heaven for those who want gas & electricity usability. The best motors are those that work on the old principals, which were bypassed due to the greedy oil and gas industry. Would be a fun project for a hybrid engine which could run on both (and even charge batteries).

 

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The best motors are those that work on the old principals, which were bypassed due to the greedy oil and gas industry.

Now that's funny !!! (forgive me for yanking your chain)

Nope... all the old ideas required an iron core and that means losses because of having to energize the core. In effect what "the master" Halbach revealed is that you can in effect "short circuit" a magnet if you place them into a Halbach array.

Halbach only discovered these properties in the 1980's while working at Lawrence Livermore Labs while doing particle accelerator research. Strictly by coincidence I was working at Lawrence Livermore Labs as a "temp" admin assistant doing silly jobs for them. (mostly copying blueprints in the print room) Since they had these bicycles in the restricted zone to ride around on I got to take lunch breaks and ride all over the lab and take sneak peaks into the work they were doing. It's likely I rode right by Halbach at least once.

Anyway... this is "the master" to worship for this new idea:

...the idea of a Halbach array is not brand new, but it being only 20-30 years old and it requiring the use of modern high powered permanent magnets means that it was not easy to do until recently. ("the master" has already passed away)

We just happen to be "lucky" to have all the necessary elements available to us today. Tesla discovered many things, but he never imagined a Halbach array.

I'm hopeful that if "we" ebikers adapt the ideas well to our ebikes that we will find a better motor concept than was possible in the past...

 

[Email]

Halbach Array = Electric Engine ~95% Efficiency
Tesla Turbine Engine = Fluid/Gas Pressure ~ 95% Efficiency

Each quite capable of driving the other... especially at high speeds.

My point is that the reason Tesla Turbine did not develop beyond what it did (and more or less was forgotten) was because prior technologies were already making headway and were using far more fuels than what the Tesla Turbine required, plus they did not have the advantage of modern alloys like we do today. The backwards logic of the gasoline industries today is to advance technology for development of new fuels and patent the **** out of it so that nobody else can produce them and undercut their prices.

If you took a Tesla Turbine and combined it with a Halbach Array you could have an engine that is very efficient at producing electric power from one Halbach array on one portion of a vehicle, and drive the wheels utilizing another Halbach array at a different portion of the vehicle. That array could utilize both battery power, and power from the small turbine/array. And sorry to burst the bubble but 80's technology is old. Yes we may just be starting to "rediscover" or apply it, but so is the case for Tesla Turbines. There's many folks out there trying to get a small diesel Tesla turbine built and into production for the developing countries.

If one were to build the vanes or discs as a Halbach array for the turbine such that they had cool air or fluid flow, the magnet array along with the boundary layer principal (Tesla's contribution) could give you the best of both worlds, perhaps instead of acting as an engine a coolant could be what flows through the engine keeping the high speed magnets from heating up and demagnetizing. Both utilize high speed spinning discs, the similarities are there. Perhaps some piezos (another ancient technology, the ideas of using crystals which respond to electric stimuli, or can create electric stimuli) to help with balance and shifting due to the strong EMFs. Technology and ideas exist, it's just a matter of putting it all together into one marketable or viable product.

And yes, the drive for an open source efficient doable design is what drives me to put out my thoughts into cyberspace instead of a patent office. If a real engine were developed that could handle high speeds, fast acceleration, and do it all low weight and efficiently etc. then it would be of benefit for not just cyclists but all motored vehicles (be they land cruisers, water craft, or air craft).

 

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At above 20 hp the Induction motor has very high efficiency. (Tesla's Motor)

Below 1 hp all sorts of problems pop up and it becomes hard to get decent efficiency.

For about a month I was studying the benefits of the AC Induction motor and there are some that are worthwhile compared to the standard permanent magnet motor, but once I understood what the Halbach design had to offer I switched.

Not needing a heavy iron core is a HUGE advantage.

Think of the massive "Big Iron" hub motors out there that weigh 25 lbs.... if you can get the same performance with just a few pounds instead then it makes the hub motor concept viable again.

The only reason I rejected the "Big Iron" in the past is because of the weight.

(the Halbach eliminates the need for the iron)

 

[AussieJester]

The only reason I rejected the "Big Iron" in the past is because of the weight.

(the Halbach eliminates the need for the iron)

...so I think the root of their problem is that they seem to think that they are destined to be the future of ebikes (the hub motors) and I just disagree because gears work so much better and are more in tune with the spirit of the bicycle.

Bicycles and ebikes should be elegant in their design, everything should be seemlessly integrated together to work as a unit.

REF: Ebikehub.com

KiM

 

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Proof that new revelations can change the status quo...

I had no idea that iron could be eliminated from an electric motor when I made that statement.

(this should underscore the amazement that the Halbach creates)

We really are dealing with a new world...

 

[AussieJester]

The only reason I rejected the "Big Iron" in the past is because of the weight.

Also suggest you have a very short memory of what you say. ^^above comment wasnt the ONLY reason at all now was it Safe.

So how long does the winter last there Safe? your going to be snowed in for months now i understand? Must suck balls for you, itching to test then look outside and you need a set of skiies to chek the mail box haha



KiM

EDIT:

Looks like recumpence is also have a run of motors built Safe...NON RC...

"The motor I am looking at building (having built for me) would be roughly 10 pounds, 4.5 inch diameter, 4.5 to 5 inches long, 30kw peak (continuous with enough cooling), 90%+ efficiency, with a 7,500 typical maximum. I could offer (would have to) a belt drive primary reduction to drop that RPM 2.5 or 3 to 1"

 

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25 lbs for a hub motor was enough for me to easily reject it as an option.

Was it the "only" reason?

I suppose not... it was enough of a problem for me to quickly get past it and reject it without looking back.

The thing that is uncertain is the behavior of the Halbach motor across a wider powerband. That's something that the AC Inductioon motor was really good at because it had the "field weakening" ability. As I see it the Halbach motor is a standard linear formula motor, but you could potentially use it in such away as to limit the motor so that it gives a flat powerband. (1K power) Actually that part is still less than certain for me.

It's "easy" to talk about "peak whatever" but it's usually the average that matters... so the details will be interesting as I learn them. (people that talk only about the peak are usually clueless about the average)

Had I known about the Halbach array in 2006 it would have likely changed the way I approached the problem. (back in 2006 all I knew was that permanent magnet motors weighed a lot and needed gearing)