Halbach Arrays

I read that one of the innovations in the PM motors Tesla is using in the m odel 3 is the Halbach array they use for the magnets. Seems this greatly i ncreases the magnetic field on one side of the magnets for little downside. The trick is being able to glue powerful magnets in an arrangement where they strongly repel one another. The guy talking about them said when they first saw one of these they put it in a vice to hit it with a hammer and t he pieces flew apart. Lol

Seems they glue four magnets together to make a single array. Not sure how these Halbach arrays are arranged in the motor. Seems the Tesla motor is much more powerful, lighter and cheaper to make than the motors used in the BMW i3 or the Chevy Bolt. The weights differ by about 10% but there was a bit larger difference in price with the Tesla model 3 motor being the top dog across the board.

Rick C.

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gnuarm.deletethisbit
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My favorite neodymium magnet seller is K&J Magnetics. They put out a brief newsletter each month, usually with a couple of short videos showing some detail of magnets and their applications. Anyway, they had a little article on linear Halbach arrays which shows the basics of refrigerator magnets with a strong field on one side and little field on the other, and a bit on motor magnets (and in a second installment).

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Regards, 
Carl Ijames
Reply to
Carl

Volt and Bolt drivetrain uses ferrite magnets in the secondary motor, they weigh more and don't perform as good.

To get the performance numbers the Model 3 has at the price they're likely using neodymium magnets across the board and betting that any price volatility will be offset by lighter weight and lower overall cost of the rest of the motor.

AFAIK most of the world's supply comes from China and they've been known to freeze exports completely from time to time.

That's less of a problem if most Model 3/future Tesla vehicles end up being primarily built in China which isn't really an option for GM.

Reply to
bitrex

Musk is a neoliberal globalist through and through the only reason Tesla is based in the US at the moment is because that's where the government/investors who give him money are.

The minute it becomes profitable to pack it all up and ship everything but the dealerships and a token Tesla North America office off to China he will. So long, and thanks for all the fish.

Reply to
bitrex

he model 3 is the Halbach array they use for the magnets. Seems this great ly increases the magnetic field on one side of the magnets for little downs ide. The trick is being able to glue powerful magnets in an arrangement wh ere they strongly repel one another. The guy talking about them said when they first saw one of these they put it in a vice to hit it with a hammer a nd the pieces flew apart. Lol

how these Halbach arrays are arranged in the motor. Seems the Tesla motor is much more powerful, lighter and cheaper to make than the motors used in the BMW i3 or the Chevy Bolt. The weights differ by about 10% but there w as a bit larger difference in price with the Tesla model 3 motor being the top dog across the board.

Not sure why you say this is not an option for GM. This is exactly what th ey have said they are going to do, make their high volume EVs in China to s ell in China before they address the US market. In fact the US market is a fter Europe too.

Rick C.

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Reply to
gnuarm.deletethisbit

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Maybe, but there are advantages to making cars in the US. Why do you think the US automakers have been doing it all these years? If they thought the y could make more money selling Chinese made autos in the US they would in a heartbeat.

Rick C.

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Reply to
gnuarm.deletethisbit

Chevy and Ford move a lot of product on jingoism; I think many American buyers would be ambivalent at the least about buying an F-150 or Silverado made in China. Price it right though and who knows I definitely don't think they'd sell zero China-150s at the right price.

Can't say I really blame Tesla I suppose, EVs are more abstractly popular in Asia and have more consistent government support. EV sales are likely to remain meh in the US for some time and government support is wildly inconsistent.

Reply to
bitrex

I would very much prefer to buy a Volt made in Detroit but if the Chinese were to make a clone with a few improvements like say charge twice as fast and price it at $25k, if it seemed at least no less well-made than the US variant I don't think I'd turn it down.

Reply to
bitrex

On Friday, January 11, 2019 at 11:27:41 PM UTC-5, snipped-for-privacy@gmail.com w rote:

model 3 is the Halbach array they use for the magnets. Seems this greatly increases the magnetic field on one side of the magnets for little downsid e. The trick is being able to glue powerful magnets in an arrangement wher e they strongly repel one another. The guy talking about them said when th ey first saw one of these they put it in a vice to hit it with a hammer and the pieces flew apart. Lol

ow these Halbach arrays are arranged in the motor. Seems the Tesla motor i s much more powerful, lighter and cheaper to make than the motors used in t he BMW i3 or the Chevy Bolt. The weights differ by about 10% but there was a bit larger difference in price with the Tesla model 3 motor being the to p dog across the board.

This video shows the Tesla 3's motor guts & magnets, starting at 3:12.

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Cheers, James Arthur

Reply to
dagmargoodboat

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hink the US automakers have been doing it all these years? If they thought they could make more money selling Chinese made autos in the US they would in a heartbeat.

I don't believe EV sales will remain "meh" in the US. But for now Tesla is the only real EV company because they are the only one with a charging sol ution. For GM and the others, it's like trying to sell razors before you c an buy blades. But that will come in time. The one report I've read estim ated it will take the competition four years to get to where Tesla is today . So they are planning on major new EVs in that time period. What if you designed an EV party and nobody came? You'd have a Bolt!

Rick C.

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Reply to
gnuarm.deletethisbit

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Yes, you might prefer a Volt, but not many others agree with you most notab ly GM.

Charging faster is not really an option until other batteries are available . Or are you talking about the slow charging of the Volt?? That option is off the table. Hybrids are not in the future of EV driving.

Rick C.

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Reply to
gnuarm.deletethisbit

No reason the battery technology it has now can't charge somewhat faster, the Leaf's Level 2 charger electronics can draw 6.6 kW. The Volt tops out at around 3.8 kW they cheeped out on the charger electronics a bit to hit a price have to save money for the gas-burner! Someone may design an aftermarket mod/hack at some point if it's feasible, dunno.

Reply to
bitrex

I see way more Bolts on the road around here than I do Model 3s...

Reply to
bitrex

I saw one Model 3 last week in a parking garage:

Does it have an auto-park system I think something's wrong with it.

Reply to
bitrex

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able. Or are you talking about the slow charging of the Volt?? That optio n is off the table. Hybrids are not in the future of EV driving.

Sorry, I thought you were talking about real EVs. In general the limitatio n on charging is presently about 1C or in other words, 1 hour. Cars that h ave lower charge rates are not likely limited by the battery, but the charg ers. 3.8 kW is about 15 amps at 240 volts. Not sure why it would be that low. The battery is good for 50 miles? That would be around 10-15 kWh whi ch should charge at about 10 kW rate or better, no? Don't know why the 3.8 kW rate...

Rick C.

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Reply to
gnuarm.deletethisbit

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think the US automakers have been doing it all these years? If they thoug ht they could make more money selling Chinese made autos in the US they wou ld in a heartbeat.

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a is the only real EV company because they are the only one with a charging solution. For GM and the others, it's like trying to sell razors before y ou can buy blades. But that will come in time. The one report I've read e stimated it will take the competition four years to get to where Tesla is t oday. So they are planning on major new EVs in that time period. What if you designed an EV party and nobody came? You'd have a Bolt!

Yeah, I know. No accounting for taste I guess.

Rick C.

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Reply to
gnuarm.deletethisbit

Probably because to go up on the charging rate from 3.8kW they'd have had to step up to the next beefier size of MOSFETs, beefier cable, different charge controller, etc. which would've added $200 to the parts cost and $1000 to the sale price

Reply to
bitrex

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ilable. Or are you talking about the slow charging of the Volt?? That opt ion is off the table. Hybrids are not in the future of EV driving.

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ation on charging is presently about 1C or in other words, 1 hour. Cars th at have lower charge rates are not likely limited by the battery, but the c hargers. 3.8 kW is about 15 amps at 240 volts. Not sure why it would be t hat low. The battery is good for 50 miles? That would be around 10-15 kWh which should charge at about 10 kW rate or better, no? Don't know why the 3.8 kW rate...

If you were talking about going from 30 amps to 60 amps I'd agree. Bumping from 15 amps to 30 amps is more like a $30 upgrade in cost. I know, I've been pricing similar components for charging and for 30 amps and under it i s pretty minimal. I think that is the reason why L2 charging units are mos tly 30 amps. I've seen none that are less and the ones that are more cost around $100 more. Mostly it is the cable and the contactor. Under 30 amps and it saves little.

Rick C.

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Reply to
gnuarm.deletethisbit

bitrex wrote

Probably had a leaking side thruster:

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Reply to
<698839253X6D445TD

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nk the US automakers have been doing it all these years? If they thought t hey could make more money selling Chinese made autos in the US they would i n a heartbeat.

There's also import tariffs, Toyota, Honda et al. have factories in the US and EU

Reply to
Lasse Langwadt Christensen

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