Thanks Sandy for this motor teardown. I can comment on the winding technology wound vs hairpin. I work with engineers to help them simulate and design these different types of windings and they both come with pros and cons. Wound windings are well known and more flexible in their design, you can make them fill a slot of any shape with a rather good fill factor. The insulation between each separate wire makes that fill factor impossible to reach 80% for instance. Designers usually can go up to 50-60% of copper in the slot. In terms of layout it is also easier to do any sort of connection as you can bend and reposition wires "easily". The cooling of these wires is not very easy as it comes as a large bundle of wire with resin/impregnation around them. Hairpin windings are a recent trend as they provide some benefits. The fill factor can be a bit higher but the slot has to be rectangular. Also as you mentioned Sandy, with higher speeds, you have higher frequency currents and then you can start to have eddy currents and proximity effects going on. It means the current goes mostly on the outside of the section, so you increase your AC losses. Also the conductor closer to the rotor and the airgap sees more varying magnetic flux density which also generate more losses as well as unbalances between wires. The connection of several paths of hairpins also creates unbalances in genral and you can have circulating currents. So in general, it looks easier on paper, or to manufacture and assemble but it means more challenges and less flexibility in the design. I think Tesla kept the wound windings for the simplicity it brings even if it may mean a slightly lower fill factor. They chose initially induction motors over PM motors for the same reason. Regarding the V shape or W shape of the magnets, it is obviously a very sensitive design depending on the performance to achieve, the magnets help for the low speed torque and the V shape acts to create reluctance torque at higher speeds. A tiny change in angle or dimension can change the torque or performance by 10% and the cost of magnet material as well. I work with Altair and we can test and simulate those several multiphysics effects. More than happy to answer any questions.
I don't work in the field, but I thought the difference in layout of the magnets might be due to the different diameters. Magnets that are placed closer to center would need to have a different angle to align to the magnetic field lines than magnets that are placed further out from the center.
Thanks for taking the time to write that. High power high efficiency electric motors are definitely more complicated than what meets the eye. Thank you for the insight ..Take care enjoy 😁
@Sandy Munro, @TheSimong85 Great explanation about the stator wiring options. Can you also comment regarding the stator water circulation that Ford and VW use without a need of a pump, versus the Tesla oil usage requiring an oil filter and a pump? I might be wrong, but does Tesla uses also the oil pressure for dissipating the heat from the rotor bearings?
Yeah he hit Elon (and Jagdeep in the QuantumScape interview) with some tough questions despite his respect for their respective advanced tech. Also even though he worked with some USA OEMs he doesn't shy from talking about their weaknesses. He and his staff have a very objective opinion about EV tech which is refreshing.
It's so rare, people publicly changing their mind when they are proved wrong about their previous public stance. Congratulation on your wisdom, if not on your first stance 😃.
@@dukequack6209 why do you think so? His previous decision doesn’t count anymore and he learned to judge better in the future. This is a good thing. Forgiveness is another 😉
@@DanielDuese he means Recognition for the things that are good does not discount the things that were bad things monkey does bad it’s still as bad it just means it does somethings good
Thanks to SpaceX, it should be possible around 2030 if they are fortunate. Without them, it would probably have take 10 or 20 more years. So the answer is No, seriously after more than 50 years it should be more than abvious.
@@robdc4829 No Nasa did, I had nothing to do with it. He is right in some ways but you are right as well. Ford choice a good company to do their motors, who already had this motor. So Apple, designs all their stuff, and their Chinese contractor, builds the items. Did Ford design this motor? If not, they at least chose a good supplier to do it for them. Good, but second place, compared to Tesla. Sorry, ask Sandy who is the bench mark for EV's.
It was fun watching Sandy and his coworker struggle to assemble the inverter. At the factory these more complex electrical sub assemblies use sequential assembly processes, fixtures, special tools and well trained assemblers. They make it look easy.
It seems that someone at Ford finally watched some of Sandy's videos. Even if they didn't build many components themselves at least they are choosing better suppliers and making an effort now.
the Problem with FUD motors and other LEGACY OEM is they are NOT building An Advanced SMART cars , they are ONLY building DUMB Electric car like an OLD FASHIONED gas car with Horse 🐎 & Buggy 🚜 Technology. in many ways TESLA is 5 years ahead of Legacy Auto, and they are pulling away.
I really appreciate Sandy's appreciation for why a designer might have done something a certain way, and how he acknowledges that good design is really hard. So many people in their reviews bashing on designs without actually knowing what is required to make a design good, they just know what they don't like. Thanks Sandy - I imagine your employees appreciate being employed by you.
I spent 10 years being a machinist 15 years as a journeyman PatternMaker .. So most of my life in manufacturing. I have a degree in electronics and applied science. So this kind of content is awesome entertainment. Thank you so much.
BorgWarner investor day presentation claimed it supplies the integrated Drive module which includes gearbox, motor and inverter? Does that mean GKN provides that to BorgWarner?
Great job, Sandy! I really like this types of videos where he explains why it's a good or bad design and show it by being able to asembly it back himself without needing an extra pair of hands! I'm sure that all guys there are very knowledgeable, but no one explains it like Sandy's. Also he has grown comfortable in front camera. Not an easy task for an engineer.
True, although the explanations are not always that great. At one point here he said 'this is a good design because, er, I like it'. Which is not exactly a compelling engineering reason :-)
Can you imagine being the engineer who designed those systems and having to watch someone tear apart and critique your baby? Glad these designers did an amazing job. Time to buy more Ford stock. 🚀🚀
It's not that the gears are great, just that forming two gears and a shaft from a single chunk of steel, instead of assembling two gears onto a separate shaft, produces a simple and reliable part.
@@1943vermork Yes, although typical modern construction would probably be to cut the smaller gear on the forged shaft, with only the the larger gear splined on; it looks like the Chevrolet Bolt is an example of that.
@@raroque12 Are you one of those Tesla fanatics. He can praise Tesla up and down but the moment he says something positive about Ford you think he's a Ford puppet? And BTW Ford didn't make the motor in the Mach-E, Magna did, he's praising Magna's engineering work.
I have a bunch of experience in Mfg in automotive watching Sandy makes me appreciate what I don’t know and want to catch up somehow. I'm and older guy at 52 but when new tech comes my way I want to get on board.. the younger people may be ahead of me but I am excited to learn and watch. Same with Sandy I think.
Hi Sandy, I don't know where you got your informations with those 70% good/rework parts. The company I am working at sells the production-lines for the hairpin stators with a rate of somewhere +90%. So I think its defenitely the more reliable way to do those stators.
Great teardown! Thanks as always. So, Ford on the Mach-e has 2 different supplier for the front and rear powertrain: Borg warner for the rear unit and Magna for the front.Toughts about this?
Mr Monroe. The skin effect, I believe, applies to high Frequency power; usually in the upper MHz or GHz rates. DC and low Frequencies use the cross area of the conductor.
This idea is correct. The depth of the skin is inversely proportional to frequency. Motors tend to run at very low frequencies (20 kHz area) where you're right. You'd use the entire cross section of the wires. A couple hundred kHz and you'd go ahead and do the calculations for completeness.
@@jackpalczynski7884 The audio fools will argue this point. I've seen some evidence that even at or just above 20Khz the skin effect can be measured. I know once you reach say 50Khz or so it certainly has some effect. My background is in electronics, however I'm certainly no expert on the subject of the Skin Effect.
It's not a stupid question; I think it's thoughtful and very reasonable. Magnetic cores use laminates aligned with the direction of magnetic flux, to reduce large energy losses which would occur due to eddy currents in solid iron. en.wikipedia.org/wiki/Magnetic_core#Laminated_silicon_steel
Whether to use the hairpin design or wound stator depends on the rotor speed. If you want to make a high rpm motor, you have to use a wound stator in order to retain efficiency. If you make a slow motor you can use the hairpin stator.
You guys are excellent, really enjoy your videos. Wondering about tapered roller bearings on differential gear. Seems like it would be more clearance critical affecting bearing load when squeezed between cases that have composition gaskets. Seems ball bearings would be less critical only concern would be to shaft shift occuring when moving from forward to reverse?
The good design of the motors has nothing to do with the Ford engineers and everything to do with the BorgWarner engineers. So out of the two things you mentioned, the Ford engineers only had to design a decent HVAC/coolant system and they couldn't do it. Ford is lucky that it can just purchase off the shelf designs for the most important systems from third party parts suppliers. If they can't even manage to keep some cooling hoses reasonably streamlined they have zero chance of designing a modern high performance electric drivetrain.
I meant to say credit goes to the Magna engineers for the front motor. BorgWarner produces the rear motor which Sandy was not as enthusiastic about. Ford gets credit for the cooling system/HVAC mess.
I learned that skineffekt comes in play at higher frequenses, so there must be a high frequens based system. It also makes inductiv components more compakt. Ewen the diff. is compact. But maybe "big part" based with exp. repear...? The inwerter looks clewerly designed. Many smaler caps. might be inustrial standard components and therefore cheeper to use. The cooling from the other side is a elegant way to do it. Nice and tidy. They found smart people to design this.
BorgWarner investor day presentation claimed it supplies the integrated Drive module which includes gearbox, motor and inverter? Does that mean GKN provides that to BorgWarner?
I was wondering, how would a model with the "front" motor at both ends, perhaps with a horse power bump, perhaps not a tire smoker but driveable for everyday use.
Silicone RTV “instant gasket” is (very) old tech. The anaerobic gasket replacements such as Loctite 518 are far better and they cure only when air is excluded. Any excess will not create lumps that can clog oil galleries and it separates like a normal gasket.
@420KinK well, definitely by not acknowledging Non-binary peoples. Unfortunately with people of Sandy's generation there are still some things they are not aware of.
Sandy was coy but honest enough to mention briefly that this marvel of an engine was designed and built by .. Magna (who makes the Jaguar EV etc ). So at least Ford chose a good subcontractor. Props to them for that. /s
Magna's engineering department gets the credit for good engineering. Ford's parts procurement department gets a participation trophy for purchasing a good product.
Magna Powertrain, which is also making similar parts for three other Ford products, Cadillac, and various German makes (VW, Porsche, BMW, etc). I'm guessing there will quite a bit of internal commonality.
@@johnroyal4913 I don't understand how the "Diff" can be shorter than the final drive gear face width? I've worked with Diffs all my working life & have Never come across one that slim. I go to the Racing trade fairs where Diffs of all manners are presented. But this Diff seems to be shorter than the length of spline on the two driveshafts that engage it????? Yet Sandy just Glossed over it ????
In an earlier Mach-E video Sandy referred to the front motor as an induction motor, presumably assuming that it would be. As confirmed in this video, it is not an (asynchronous) induction design - it is a typical interior permanent magnet synchronous motor.
@@harsimranbansal5355 No, "induction motor" has a specific meaning in electric motors, and clearly that's what Sandy meant (and was wrong about). Yes, windings are inductors, but saying "Technically all motors are induction" is as nonsensical as saying "Technically all motors are resistance", because all wires have resistance. In the term "induction motor", the "induction" refers to current induced in rotor conductors (windings or cage) by changing stator magnetic fields, producing a rotor magnetic field for reaction. That is not how this motor works; there are no conductors in the rotor and the motor does not work by inducing rotor current.
@@abraxastulammo9940 Perhaps. One of the VAG platforms uses induction motors at both axles, but he knew that the Mach-E was IPM at the rear. I think he was assuming that everyone would do what Tesla did in the Model 3/Y (which is IPM rear and induction front), but even Tesla doesn't do that in the Model S/X.
Ford decided on a spec, decided on the space available, went to suppliers and asked them to tender. Magna won..... The ford designers were happy. No in house design.
What I want to know is did Ford have anything to do with the design of this motor or was it all Magna, and Ford just basically bought this off the shelf. I have a 2017 Ford focus electric, and I believe the powertrain in it was completely designed by Magna.
Magna is a Tier 1 supplier - that means it supplies parts directly to the assembly line in a just-in-time fashion. Ford, GM, and Chrysler got rid of alot of their in-house people and went to suppliers. That's why Magna became such a huge company - it took on the work that the "big 3" in NA were outsourcing. Magna also builds entire vehicles. They are building the Fisker vehicle. They recently entered into a Joint Venture with LG to produce electric drivetrains, inverters, and other systems. The traditional automakers going forward will very much depend on suppliers like Magna for electric systems. That's not a bad thing, Magna employs 169,000 people worldwide and they in turn have their suppliers for stuff, also worldwide. Besides, with Magna building so many different parts for so many different vehicles, they are in a position to draw on their experience on what works best, where. We shouldn't be surprised at seeing some innovative designs from a supplier like Magna.
"Skin Effect" is caused by all the electrons in the wire repelling each other. This is why multi-stranded cable can carry more current than a similar mass solid conductor. Stranded wire has more surface area.
Does skin effect matter at EV motor inverter frequencies? So far as I can tell, most EV manufacturers are using frequencies between 2 kHz and 10 kHz. That's pretty low frequency and results in pretty thick skin depth.
SANDY , if you guys haven't seen the Ford Mach E 1400 prototype commercial that Ford produced , you guys must watch it. It is pretty pretty amazing and that video really shows that Ford does have some good stuff under that hood. Maybe not the battery advantage but their motors don't mess around.
When Sandy says better he means cheaper to build. Tesla chose the wound method because it’s cheaper but the other method offers more fill and is mostly seen as better but more costly and complicated to build.
@@Icayn Better has lots of components, one is cheaper, which is cost of components, ease of manufacture, failure rate. Better also includes; efficiency, durability, predictable characteristics, etc.
@@davidharris7249 I agree, but my point is Sandy only gauges “better” by what is cheaper to manufacture. It’s a fault of his in my opinion, he couldn’t care less about ease of service, long term reliability, cost of repair, or even final cost to consumer. He obsesses over fewer screws, and fewer parts, no matter the cost to the consumer.
@@Icayn Agree, but he does stress that in EVs every gram saved means better efficiency and more range -- and less cost in parts and manufacture, and a better product if done right. Elon: the best part is no part.
@@davidharris7249 not sure that approach is best for the driver/consumer in every case. The Germans say to heck with efficiency and just use a bigger battery. This allows them to give us superior build quality and more traditionally luxurious interiors and higher levels of refinement. All the screws VW likes to use cuts down on noise harshness and vibration. That matters to me. I don’t care if they used one stamp to make the entire car at the factory, I care about comfort, reliability, and cost to own long term.
I would love to see the thermal pathway in action on that inverter cooled setup. Those pockets look like they could be isolated to not cool off as much as they should.
23:50 I don't like spring connectors in IGBT circuits. The slightest misconnection (maybe due to vibration) makes the whole inverter blow up immediately.
You can design these to withstand vibration deterministically. Vibrations are stated in terms of acceleration and as long as the spring has a higher force them the maximum possible acceleration times the mass of the spring contact, it won't disconnect. According to studies, they are often more reliable than Pressfit and especially Screw-Terminals. This is also because the contacts on the IGBTs don't need to handle any forces except the spring, so the bonding wires won't be loaded.
Water has enormous heat capacity compared to air, so you need far less of it to get the same cooling. The tradeoff is that while {filtered} air is a good insulator, water with stuff dissolved in it cannot safely make contact with any of the live wires. Lots of design conflicts arise here - tricky business...
The industrial motors you might be thinking about are rated for 24x7 operation at 100%, sometimes even more. Also they require no "external parts", ie water cooling system to work. Electric motors in EVs can deliver a huge peak power, but they are not rated to work at 100% all the time. If you see any EV accelerating, it will reach max speed (legal or driver desired), in a few seconds, maybe hitting 100% power output. Once the car is at constant speed, it will consume an smaller amount. An EV at 100~120 km/h consumes about 20~30kW even on a climb, way less than peak power. The EV motors can operate continuously at this "low" power numbers with liquid cooling without issues.
So Magna did an amazing job on the front PM motor, but Borg Warner did a not so good job on the rear. Why did Ford contract two different companies? Why not just pick the better design for both front and rear?
Maybe because it's for Ford an new technology that needs an reduancy backup. If the back motor breaks you still have an front motor. And the other way around. So you still get with your car home. They're looking which motor system will last longer? Don't but all your eggs into the same bucket.
Sandy call out poor deign and implementation for what it is. If that’s rude then perhaps it’s what’s need to get the providers to improve their product. I have never seen him aggressive or rude to people. He’s direct but he’s not disrespectful.
Once again, great dissection Dr. Munro! So wouldn’t an oil filter in a lubrication system increase the longevity of the device? I imagine Tesla having more electric vehicles on the road than anyone else might have a evaluated this, no?
A gearbox in an EV is similar to a rear diff in an ICE car. They don't have pumps or filters and they last the life of the car. It seems to me Ford has more experience making transmissions than Tesla.
@@davidharris7249 no but they know how to find some one that will make a gearbox that will last for the correct price. They have been doing this for a long time.
@@alesksander Tesla is absolutely right, with the way they are continuously in the media's crosshairs they can't afford to have vehicles burn to the ground because someone had no idea what they were doing. The media won't make the distinction and they'll just run the story.
@@boostav Exactly. The first "man electrocuted by Tesla" headline would be unfortunate, but nothing to do with Tesla. MSM, etc, wouldn't care Rich already had "an incident" at his workshop while playing.
@@alesksander AMEN! Tesla needs to fix course and stop opposing Right to Repair. Greed bags. Any excuse they come with is just that: corporate bs. The cultist brigade members then have their talking point to echo all over the internet. Wake up, those of you that aren't bots. RIGHT TO REPAIR
@@HillslamsMirror Keep crying. Right to repair won't be given for highly sophisticated products until the people working on them are from the 20th century. I personally won't trust an ICE mechanic to handle my EV.
So happy to see other companies improving and getting thins done right. Except for the cooling and some extra weight, the Mach-e seems to be a really good vehicle.
@@neeljavia2965 Mach E descending the Geiranger Fjord in Norway left 6 drivers stranded and there is also a video from USA of Mach E going into panic mode descending a high altitude road. 😱
6:20 gasket vs rtv? Which is more likely to leak after years of service? I’ve had rtv that just stays glued like no tomorrow and would be a better choice for long term service and no issues.
Nice IGBT modules. The integrated water cooling fins and contacts are well thought out. The DC input buss bar is also extremely well done. Keeping the positive and negative plate close and parallel minimizes input inductance and RF noise. You can see this pay off because the don't need a DC input filter inductor and capacitor to keep RF noise inside the inverter. Would not be surprised if the power input pins to the IGBT modules alternated + - + - + to minimize inductance as well. Like the intermediate gear in the gearbox too. Adding the long shaft between the large input gear and small output gear provides enough space to fit a standard gear Hob tool. Is the differential a spur-gear planetary design? They have a few more parts than a bevel gear design, but can be extra compact.
Ford shills: “Sandy doesn’t know what he’s talking about”. Sandy: “I love this Mach-E gearbox and differential”. Ford Shills: “Sandy really knows his stuff, he’s a genius engineer”. Sandy: “Tesla were right, a wound stator is better than the Ford stator”. Ford shills: “Sandy doesn’t know what he’s talking about”.
So what you're saying is that the car designers aren't complete idiots and may have done particular things for a reason that sandy isn't aware of. But sandy also isn't a idiot and may make some good suggestions. And keyboard warriors probably know less than either.
Hi Sandy . Part of the cooling system purpose on the motor is to stop the neodymium magnets from demagnetising due to heat and it is a rather great loss of greater than 95% from just one time of coolant loss. You should do a simple experiment for the audience with a magnet and heat gun . Use a temp sensor on multi meter and have the magnet holding a weight that i can just handle. Heat the magnet and see at what temp it lets go . Once it lets go it will never regain its flux strength again . Probably won’t even hold a paper clip ! It is a very important consideration with electric cars as over time with bad design the magnets will lose strength and some people might only think its the battery losing capacity! 👍🏻
If the rotor gets to the temperature, your bearings would have locked completely and torn apart at that point. If temperature raises too much the computers (inverter or some other module) will not allow the car to continue.
The front and rear have two different sets of requirements (for power, space, weight, etc), which were met by two different product, which happened to come from two different suppliers.
