Tesla M3 teardown information video - Hallbach Array Motor

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MitchJi   1 GW

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Tesla M3 teardown information video - Hallbach Array Motor

Post by MitchJi » Jan 04 2019 6:06pm

Sandy Monroe discovered that the Tesla model three permanent magnet motor uses a Hallbach Array! That means the Square root of two efficiency and power increase! That is 1.41! Huge difference!



Oops 😬, fixed incorrect tags!


He was also very impressed with the HVAC system which he mentions is reviewed in this jalopnik article:
https://jalopnik.com/the-tesla-model-3s ... 1830992728
Best Wishes!

Mitch


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Re: Tesla M3 teardown information video - Hallbach Array Motor

Post by Arlo1 » Jan 04 2019 8:09pm

MitchJi wrote: ↑
Jan 04 2019 6:06pm
Sandy Monroe discovered that the Tesla model three permanent magnet motor uses a Hallbach Array! That means the Square root of two efficiency and power increase! That is 1.41! Huge difference!


Oops 😬, fixed incorrect tags!


He was also very impressed with the HVAC system which he mentions is reviewed in this jalopnik article:
https://jalopnik.com/the-tesla-model-3s ... 1830992728
I don't believe its a halbach array. I am hopping Biff or others in the know will explain in further detail. And the Square Root of two thing is pure BS. Square root of 2 is a calculation from peak to RMS. The things limiting power in the motor are more than just the magnets. You can't magicly change the magnets and expect the motor to have 1.41x more power it doesn't work like that. As well if its a partial reluctance motor it would then not rely on the magnets as much for something to interact with the fields produced from the stator.
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Re: Tesla M3 teardown information video - Hallbach Array Motor

Post by billvon » Jan 04 2019 11:20pm

Arlo1 wrote: ↑
Jan 04 2019 8:09pm
I don't believe its a halbach array. I am hopping Biff or others in the know will explain in further detail. And the Square Root of two thing is pure BS. Square root of 2 is a calculation from peak to RMS. The things limiting power in the motor are more than just the magnets. You can't magicly change the magnets and expect the motor to have 1.41x more power it doesn't work like that.
Agreed. It's like saying that if you eat 1.4x the sugar you'll be 1.4x stronger and faster. There's a bit more to it than that.
--bill von

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Re: Tesla M3 teardown information video - Hallbach Array Motor

Post by MitchJi » Jan 07 2019 11:52am

Arlo1 wrote: ↑
Jan 04 2019 8:09pm
MitchJi wrote: ↑
Jan 04 2019 6:06pm
Sandy Monroe discovered that the Tesla model three permanent magnet motor uses a Hallbach Array! That means the Square root of two efficiency and power increase! That is 1.41! Huge difference!
I don't believe its a halbach array. I am hopping Biff or others in the know will explain in further detail. And the Square Root of two thing is pure BS. Square root of 2 is a calculation from peak to RMS. The things limiting power in the motor are more than just the magnets. You can't magicly change the magnets and expect the motor to have 1.41x more power it doesn't work like that. As well if its a partial reluctance motor it would then not rely on the magnets as much for something to interact with the fields produced from the stator.
Did they come up that theory to explain the power and weight that they obtained in their testing?

Unrelated question. What relationship does higher voltage (800 vs 400) have to higher charge rates?
Best Wishes!

Mitch


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Re: Tesla M3 teardown information video - Hallbach Array Motor

Post by liveforphysics » Jan 07 2019 3:12pm

I think the root cause may be that nobody at Monroe seems to grasp basics of EV energy storage or powertrain.
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Re: Tesla M3 teardown information video - Hallbach Array Motor

Post by Arlo1 » Jan 07 2019 3:34pm

I agree Luke. And Mitch there is no relationship to voltage and charge rates. You can have 1/2 the voltage and 2x the amps or 2X the voltage and 1/2 the current....
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Re: Tesla M3 teardown information video - Hallbach Array Motor

Post by grindz145 » Jan 07 2019 4:12pm

liveforphysics wrote: ↑
Jan 07 2019 3:12pm
I think the root cause may be that nobody at Monroe seems to grasp basics of EV energy storage or powertrain.
This was exactly the feeling I got after watching the video...

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Re: Tesla M3 teardown information video - Hallbach Array Motor

Post by TilmanBaumann » Jan 07 2019 4:37pm


MitchJi wrote: Unrelated question. What relationship does higher voltage (800 vs 400) have to higher charge rates?
Mostly a question of wire thickness in the case of DC fast charge. The charge cable and plugs can only support a certain amount of amps.
To get more power through, you need to raise the voltage.

Copper is expensive and heavy. And power electronics tend to scale in price more with amps than with volts.
High amp onboard chargers are bulky.
All good reasons to go high voltage.

Another point where voltage matters for change speeds is the extreme low end. Chademo doesn't really work well below roughly 150V. CCS iirc has a similar limit. That is why zero motorbikes don't have fast charge.

The future of performance EV seems to be high voltage if you read the current developments on that era.

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Re: Tesla M3 teardown information video - Hallbach Array Motor

Post by Hillhater » Jan 07 2019 5:50pm

TilmanBaumann wrote: ↑
Jan 07 2019 4:37pm
The future of performance EV seems to be high voltage if you read the current developments on that era.
yes. Note the latest FE cars run 900volt systems..battery included.
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Re: Tesla M3 teardown information video - Hallbach Array Motor

Post by Punx0r » Jan 07 2019 6:03pm

So why doesn't the engine in my road car rev to 15,000 rpm like an F1 car?

Do everyday vehicles perhaps have different engineering priorities compared to gram-shaving, money-no-object, balls-to-the-wall racing machines?

~400V is a common upper limit for everyday electricity in an industrial setting, presumably because it's an acceptable trade-off between safety, environmental tolerance and power density - bearing in mind wiring runs are typically far, far longer in a building than a vehicle.

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Re: Tesla M3 teardown information video - Hallbach Array Motor

Post by Hillhater » Jan 07 2019 9:11pm

If you rode a M'bike or drove a Tesla, you might just find your engine does rev to 15k !
And if you worked on a Toyota/Lexus hybrid you might also find 7-800volt drive systems.
The race track in often the birthplace and prooving ground of tomorrows road car technology.
Industry uses a whole range of voltage systems, and 800-1000+ v is not uncommon (EAFs)
And dont forget the Nationwide grid system is based on many thousands of volts. With many thousands of people used to working in that environment every day.
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Re: Tesla M3 teardown information video - Hallbach Array Motor

Post by TilmanBaumann » Jan 08 2019 3:21am

There might be a different safety certification process involved for electricians working on the car.
But probably not. 600v DC kill you just as much as 900v DC.
Bosh iirc offers powertrains that can be serviced my non HV certified garages. But they are very meager power.
Won't be long and all garages are certified for proper EV work.

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Re: Tesla M3 teardown information video - Hallbach Array Motor

Post by madin88 » Jan 08 2019 3:40am

Arlo1 wrote: ↑
Jan 04 2019 8:09pm
I don't believe its a halbach array.
Yes i also think that it would not make sense to use a halbach array on an IPM motor (where the magnets are surrounded with steel), as the main advantage of halbach would be that it doesn't require steel for flux return. So why?

Tesla was using four single pieces of magnets in each slot, but i believe the guy did not interpret this right and those four pieces are segments in order to lower eddy current losses in the magnets itself (for the same reason as why we using steel lams on stator on and rotor).

Here a picture of the Model 3 rotor where the intersections between the magnets are visible:

Image

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Re: Tesla M3 teardown information video - Hallbach Array Motor

Post by MitchJi » Jan 08 2019 9:22am

madin88 wrote: ↑
Jan 08 2019 3:40am
Arlo1 wrote: ↑
Jan 04 2019 8:09pm
I don't believe its a halbach array.
Yes i also think that it would not make sense to use a halbach array on an IPM motor (where the magnets are surrounded with steel), as the main advantage of halbach would be that it doesn't require steel for flux return. So why?

Tesla was using four single pieces of magnets in each slot, but i believe the guy did not interpret this right and those four pieces are segments in order to lower eddy current losses in the magnets itself (for the same reason as why we using steel lams on stator on and rotor).

Here a picture of the Model 3 rotor where the intersections between the magnets are visible:

Image
Okay, this is all over my head. Another comment/question. They did say that the magnets exploded when they hit them with a hammer. That means that they are aligned in a way that they are pushing themselves apart . What does that mean?
Best Wishes!

Mitch


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Re: Tesla M3 teardown information video - Hallbach Array Motor

Post by fechter » Jan 08 2019 9:31am

MitchJi wrote: ↑
Jan 08 2019 9:22am

Okay, this is all over my head. Another comment/question. They did say that the magnets exploded when they hit them with a hammer. That means that they are aligned in a way that they are pushing themselves apart . What does that mean?
It depends on the plane the magnet fractures in. In one plane, the pieces will stay attracted by magnetism. In the other two planes, the pieces will strongly repel and try to flip over to be in the attracting direction. If you take two bar magnets and try to put them side by side, you will see how this works.

When you hit one with a hammer, the fractures will be sort of random but more likely to break along one of the repelling directions due to internal stress.
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Re: Tesla M3 teardown information video - Hallbach Array Motor

Post by Arlo1 » Jan 08 2019 11:10am

fechter wrote: ↑
Jan 08 2019 9:31am
MitchJi wrote: ↑
Jan 08 2019 9:22am

Okay, this is all over my head. Another comment/question. They did say that the magnets exploded when they hit them with a hammer. That means that they are aligned in a way that they are pushing themselves apart . What does that mean?
It depends on the plane the magnet fractures in. In one plane, the pieces will stay attracted by magnetism. In the other two planes, the pieces will strongly repel and try to flip over to be in the attracting direction. If you take two bar magnets and try to put them side by side, you will see how this works.

When you hit one with a hammer, the fractures will be sort of random but more likely to break along one of the repelling directions due to internal stress.
Also when you break a magnet in to multiple pieces each new piece has a North and A South so it will be very likely some parts will want to repel others.

Another point is a proper halbach array needs 5 magnet. He shows 4 sections.

One more point to disprove this is how the magnetic fields flow in the rotor of the IPM motor.
Attachments
Magnetic-flux-trajectory-according-to-the-direct-and-quadrature-axes-in-a-4-poles-IPM.png
Magnetic-flux-trajectory-according-to-the-direct-and-quadrature-axes-in-a-4-poles-IPM.png (32.15 KiB) Viewed 1011 times
Capture.PNG
Capture.PNG (171.62 KiB) Viewed 1011 times
Does your project need a high performance motor drive, battery charger or other power electronics developed? Let's talk!
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