Tesla Model 3 and Y Modular Motors

Hello, I'm Professor John Kelly, and  this is the WeberAuto YouTube channel. Today we're going to look at the Tesla  Model 3, rear and front motors, and the equivalents that go in the Tesla  Model Y, also, but let's begin with the rear motor for the Tesla Model 3.  Now, as I've been exploring these different motors and drive units, on  the Model 3 and reading about the Model Y motors, I've found some interesting  things that I think you'll get a kick out of. So let's, let's take a look at these.  First, the rear motor for the Tesla Model 3. As you may have seen in some  other videos, used as a permanent magnet-based rotor, you know, in other  words, there are magnets inside of this, it's called an internal permanent magnet  rotor. And this rotor has a shaft that goes all the way through. This has some  splines right here, that hook to an input shaft that is going to drive some  other gears to make the vehicle move down the road. We've got some nice SKF  bearings right here. And bearing on the other side. I'm going to put this rotor  and input shaft into a mock-up that me and my shop assistant built. And  let's take a look at how this thing is connected together. And then we'll talk  about what's common between all of these motors. So let me get this  motor put in place first.   Okay, as you can see, I've got it placed in some v blocks here.  And we can just spin the rotor in the V blocks on its magnets. These, these  bearings that it's spinning on are not ceramic bearings. These are some high  quality, SKF bearings made for high RPM because this motor also spins at a  very high RPM, close to 19,000 RPM at its maximum vehicle speed on the performance  version of the Model 3. But let's take a look at the other gears and  components involved here. So this gear that we have right here, that's on the input  shaft has 31 teeth, and it is going to drive another gear here on this  countershaft that has 81 teeth. So if we run that over here put it right down in its  v-block. Get the gears lined up, we have 31 teeth driving 81 teeth, and that gives  us a gear ratio between those two of 2.6129. And the countershaft has another  gear a smaller gear that has 24 teeth on it, and it is going to drive our  great big ring gear right here. This ring gear is the same diameter as the Model S  ring gear that we looked at in previous videos 213 millimeters, it's a little  bit wider than the front ring gear that used to be 40 millimeters on the Model  S This one is 46. The rear one was 50 I believe. So it's the same diameter just  a little bit narrower than the gear on the rear of the Model S and it uses these  same gigantic bearings that the Model S used to handle all of the torque that  is supplied to this differential case, the ring gear is held on with 16 bolts  just like the other Model S's. This has an open differential style differential  and so now we are going to set this differential case with ring gear with  its 83 teeth down into the V blocks right there. So now we have the 24 teeth of the counter  gear driving the 83 teeth of the ring gear and that gives it a gear ratio of  3.4583 to one between the countershaft and the ring gear. And then if we do an  overall gear ratio between the electric motor shaft the input shaft, the counter  gear, the small gear on the counter gear and the ring gear on the differential  there, we end up with an overall gear ratio of nine Point 036321. Now  I noticed in the owner's manual and on Tesla's website for the Model 3, and  the Model Y, they just list this as a nine to one gear ratio. But it's not  nine to one that would be a hunting gear set, we want a non-hunting gear set,  we don't want the same teeth coming in contact every nine revolutions. So we  have a gear ratio of 9.0363 to one. So now, that means that I have to rotate  this permanent magnet rotor 9.0363 rotations to get one revolution of our  ring gear. Now the ring gear has side gears that connect to it. And that  is where our axle CV shafts or half shafts come in. Okay, the way I have this  facing, this would be the rear of the car, this would be the front of the car.  And there. Once again, as I spin the electric motor rotor, the permanent magnet  rotor 9.0363 times our CV half shafts turn our hub and bearing assemblies  and our tire and wheel assemblies, one revolution. So this motor spins a little  over nine times faster than your tires. Okay, these are all the moving parts  that are inside of the Tesla Model 3 rear drive unit, the rear electric motor.  This is as I mentioned, a permanent magnet rotor. So I have a permanent magnet  right here, a neodymium magnet from a Toyota hybrid electric rotor. And I just  want to show you, I'm not holding it here in my hand, that if I bring that  magnet anywhere near this rotor for the Tesla, I can make the Tesla rotor rotate,  just moving the magnet back and forth. These are very strong magnets. also kind  of an interesting demonstration here. If we, if you watch this  magnet in my hand, right here,   if I turn changed directions, then it goes the other  direction. That's because of all the different sets of magnetic poles that  are in here. This is not an induction motor, like they use in the front of  the Model 3 and Model wide vehicles. So this is a permanent magnet-based electric  motor. And there's some really cool videos on how the design of this works  and, and how the permanent magnets are aligned with other pieces of the  rotor itself. But that, which is very impressive, but check this out. What I  think is really cool about the overall design of the front and rear drive  units for the Tesla Model 3 and Model S is that they are actually modular,  meaning we can you can change just a few pieces that make it a different motor.  So if I take out this permanent magnet rotor right now, so I'm just going to  lift it out. It's pretty heavy. I'm going to take off the input shaft, and  I'm just going to set this rotor very carefully off to the side over here. And  now we're going to change this entire unit to the front drive unit. So to change  this to the front drive unit, I need to bring in a different rotor. This is a  copper core, induction motor rotor, and we're going to take that exact same  input shaft that slid onto the end of our permanent magnet rotor over here for  the rear drive unit. And we'll slide it right on to the induction motor for  the front drive unit. And watch this. Set that right up in there. Align the  bearings and now we have the front electric motor, the front drive unit,  all the other parts are the same. How cool is that? The exact same part number so I've  checked them all out. I've got both a front and a rear drive unit apart on the  benches. Over here behind the camera, and they have the exact same parts inside of them. So for manufacturing and costs that's  a really cool idea because it uses all these common components, you don't have to produce all these other components  for different designs of axles, we have the exact same gear ratio on the front  exact same number of gear teeth, exact same bearings, it's all the same internal  pieces, we have the same oil pump the same oil filter the same oil cooler.  The only thing that has to be different with the change in the rotor is a change  in the inverter and the stator, this the part the big three-phase stator that  the rotor slides into. So, there are different power ratings for different  electric motors on the Model 3, you can get a rear-wheel-drive only, which  is the permanent magnet one, you can get a standard all-wheel drive, which is  the permanent magnet in the rear and the induction motor in the front, you can get  a performance all-wheel drive that has the permanent magnet in the rear and  the induction motor in the front. But at higher power, the internal guts are  the same, but the inverter and the stator, either give it more power or  not the inverter in this state are a matched set. By the way, I'll bring  in the permanent magnet again from the rotor of a Toyota Prius and notice that  it has no effect whatsoever on this rotor for the induction rotor for  the front motor on the Model 3 and the Model Y. And then what's really  cool is I was watching a video from Sandy Monroe several months ago about  the Tesla Model Y front motor. And he pointed out that even a different rotor  for the Model Y that did not have a copper core, it had an aluminum core.  And so there are at least three different rotors for this same gear combination  here, which I suspect the aluminum rotor aluminum is not as good of a conductor  as copper is. So that's probably the standard nonperformance version, front  rotor, and possibly the copper one is for the performance one only, I don't know  for sure. But I that's what I that's what I suspect. So that's pretty cool.  The common components of the rear motor, the front motor for the Tesla  Model 3 and the Model Y, the part numbers for all of these motors in the  Model 3 and the Model Y are identical for the rear motors, I can't find the  part number of the front motor for the Model Y the drive unit. But I suspect  from looking at the outside of the case that it's the same as what we've  got here just has that different aluminum rotor. Okay, let's take a look  at the rest of the common components that you'll see in the Model 3 and  Y rear and front motors. Okay, let's continue with what else is modular, what  can what is almost interchangeable from one drive unit to the next on these on  this modular design of these Tesla Model three and Model Y drive units. So I have  an empty drive unit housing right here. And this drive unit. I've taken the gears  out of I showed you those in the first part of this video. But what I want you  to see is that on this side of the drive unit, there's a big opening for the  inverter and the inverter is the electronics that takes power on these two wires  from our high voltage battery DC power changes it to AC power sends it out on  these three terminals to these three cables. So in the drive unit, this bolts  up right there. And this drive unit inverter bolts onto the side of the drive  unit housing and it has a Part number on it this drive unit inverter  1120970-00-D and if you notice, right Here on this stator assembly, it  has the exact same Part number on it. So that means I believe that the inverter  and the stator assembly are a matched set to deliver one of three different power  and torque ratings available on the Model 3 in the Model Y, we have the  rear-wheel-drive only version, we have the standard forward or all-wheel-drive  version. And then we have the performance all-wheel-drive version.  So there are three different sets of inverters. And stator assemblies is  my theory. I've been able to find photographs on eBay of parts for sale  from those different models. And there are a whole bunch of different variations  of these over the year since 2017, when the Model 3 first came out. So the inverter bolts up here on the  one side, let me take that back off. But let me also go get the front inverter  and bring it over. So here's the inverter for the front motor of the Tesla Model  3. And if you look at it, it looks just like the one that we just took off  and set right over here for the rear motor. But this rear motor is a permanent  magnet rotor, the front motor has an induction motor. So the circuit board is a little bit  different. Possibly the transistors are different that are used there. But I want  you to see that this also bolts up to the exact same bolt pattern on the  rear motor. So I'm not saying that you can swap parts around I'm just saying for  Tesla, for the design to just have one size of casting one size of circuit board.  It's and make it all interchangeable. If you want to. Maybe if you wanted to  switch from a standard range to a higher power version, you could swap out the  inverter and the status assembly and make n rotor and make that happen and leave  all of the internal gears as we saw there are the same for Model the Model. Alright,  if we turn this drive unit housing around, we have this big round opening  here. That round opening here is for our stator assembly, we have our three-phase  cables right here. They are going to go into these three holes right here. This  bolt pattern lines right up. There's a gasket or aluminum gasket that goes on  there and bolts this and these three phase cables to the three copper terminals  on the inverter. There's the access plug right here, this orange plug on the  side, that is the bolts that connects the three-phase cables to the inverter.  So if you ever took an inverter off or a rotor or a stator off, you'd have to  first take this cover off and take the bolts out so that we can separate the  separate the two. Alright, the stator is oil-cooled. This takes a special ATF  nine it's kind of a purple-colored transmission fluid. There is no coolant  running through this transmission. It's all oil-cooled, and then it has a heat  exchanger right here that this is the exact same part number heat exchanger  that's on the front drive unit. This is the rear drive unit. But we have the  transmission fluid pumped through the bottom here. We have coolant coming in  the top here and an exchange exchanges heat to cool or warm the transmission  fluid. Down here at the bottom of the housing we have a place for a variable  speed electric oil pump that fits in here. What's nice about the variable speed  oil pump is that we're not reliant on a gear driven oil pump like we were on  the Model S versions on the Model S the rotor bearings and all the input shaft  bearings had to be kept cool and well lubricated especially at the higher RPMs  at the higher vehicle speeds and that didn't happen until the vehicle speed  was higher to drive that oil pump faster. Well on the Model 3, we have a variable  speed electric oil pump that can pump coolant, or the transmission  fluid, which is the coolant in this case through the bearings and not only that  through the state or to cook to help cool the stator because it's, it's the  transmission fluid that cools the state or assembly here. And so that is a huge  advantage over a just a gear driven oil pump. And then we also have an oil  filter an external filter that screws on right here. And if there was ever a  failure of any type, you can flush it out and change the filter. So we have the  exact same part number for the oil pump and the oil filter and the heat exchanger  for the rear motor as we do the front motor, the front drive unit. So a lot  of common parts, the modular components that make up the differences or makeup  commonality between these now the differences are the cases themselves,  these housings here are different. And the main reason for that is in the back of  the car, the oil pump always sits at the lowest spot that have horizontal so that  the fluid, the transmission fluid will go into the pump and then be pumped  around. And the housing is pretty much parallel with the ground on the  rear drive unit but on the front, it's tilted. It's kind of tilted like this.  And so as you'll see when we get over there, the oil pump is moved  over to a different location. And so these housings are not  interchangeable, but the bolt pattern for the inverter and the motor are the same,  the bolt pattern for the heat exchanger is the same and the oil filter and the  oil pump. Alright, let's look at the front drive unit next. Okay, on our front  drive unit, you can see the oil pump housing with the transmission house  transmission housing mounted about like this pointing down in the vehicle.  The oil pump is now towards the bottom with our oil spin-on oil filter next to  it. So that's different than the rear, but it's still the exact same part  numbers. These axle seals are the same part number. Here's our heat exchanger  for the transmission fluid going through to get cooled. And then if we come  over here and look at the rotor, or the stator. Notice this stator is  considerably shorter than the rear one and that's because the rotor isn't as long  as the permanent magnet rotor on the rear motor either but this is an induction  motor or stator assembly right here. And then here is our inverter for the  front motor. The inverter is also liquid cooled has coolant with a coolant  inlet and outlet over here is a coolant passage that goes through to cool either  the MOSFET or the IGBT transistors in there that run the current through  the state or assembly here. This sorry, this front stator will not bolt  up to the rear housing. Even though the bolt pattern is the same, the clocking  the position of these three-phase cables is different on the front than it  is on the rear and so they are not interchangeable. And the reason for that  is the placement of the stator and the cooling drain and feed versus the inverter  with the transmission housing tilted has to be different than on the front  one. But I want you to see that the part number here for this stator or  this stator. Yeah, is 1120960-00-F and then it has its matching part number  right here. It's upside down, but on the stator or the inverter assembly.  So once again, these are a matched set these bolts Gather just like this.   And it's my theory that the different levels of power and torque come from different  combinations of inverters and stators. Or maybe just the inverter is what's  different and the stators are the same, I just don't know. But I, I wanted to show  you what I thought was really cool in these drive units for the Model 3 and  Y front and rear in that they have so many identical parts, which I think  is a really cool design. Now I know I did not go through and deep deep detail on  how these drive units are, how they work and how the oil flows through them and  all that and I'll do a different video a little bit later showing you the internal  pieces and the and the cooling and oil passages through the transmission, housing  and so on. But this is just a quick semi quick video for my videos. Mine are  usually long on the common components on these modular transmissions. So I  hope you have enjoyed this video. We do offer through this website here at the  bottom of the screen and in the video description. Additional hybrid and electric  vehicle training we have some online classes and a five-day boot camp that  we run four or five times a year. So if you're interested in additional education  on hybrid and electric vehicles, you can sign up for that. Also, if you feel  like you have benefited from this video or my other videos, please consider a  donation to the automotive department here at Weber State University. There's  a link at the bottom of the video description where you can donate directly  to our department to help us obtain more components and cool things to  show you in additional videos in the future. Thank you for watching.

Channel: WeberAuto

Views: 456,809

Keywords: WSU, Weber State Automotive, Weber State University, John D. Kelly, Guy in Wheelchair, Professor Kelly, EV Boot Camp, Utah, Layton, WSU Davis, Weber State University Davis Campus, Tesla Model 3, Tesla Model Y, Tesla motor, Tesla, Tesla Drive Unit, Tesla Performance, Modular, Drive Unit, ATF-9, Weber Auto

Id: SRUrB7ruh-8

Length: 27min 56sec (1676 seconds)

Published: Sat Jul 03 2021

Reddit Comments

[u/[deleted]]

Cool, I really enjoyed his teardown of the Model S motors and learned a few things. I will definitely enjoy watching this new video.

[u/FitzwilliamTDarcy]

TL DW?

[u/tsm106]

Very cool video, thx for sharing.

[u/dallatorretdu]

thanks for the video, I love watching how things work out. This is a departure from the same Sandy Munro video

[u/tesrella]

Is Sandy not the gold standard? Does somebody who knows a lot about transmissions know much or anything about electric motors?

[u/Split_Seconds]

Is this also for the SR+ rear motor?