# Tesla motor without gearbox?



## Tremelune (Dec 8, 2009)

I'm seeing some Tesla motors available for a few grand these days. I'm wondering if they can be used without the gearbox attached, such that you could mate the output shaft directly to an ICE manual transmission, lovejoy coupler, or differential...

Lots of work is and has been done with regard to controlling Tesla motors, so to be able to use some of the smaller ones where you'd otherwise be putting a Warp or Hyper9 for the same money is compelling...

Seems like the big issues would be sealing the mating face, relocating the inverter, and "trimming" away the excess where the gears used to be...then you're only left with the existing difficult task of mating the output shaft to the input shaft...

After that, you might wind up with a compact little monster.


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## Hollie Maea (Dec 9, 2009)

I'd probably use a Leaf motor in such an application. A lot easier to get to the state you want.


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## electro wrks (Mar 5, 2012)

Here's a separate Tesla motor drive on YouTube starting @ ~5:45 : https://www.youtube.com/watch?v=2v-5GB7i10o


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## brian_ (Feb 7, 2017)

Tremelune said:


> Seems like the big issues would be sealing the mating face, relocating the inverter, and "trimming" away the excess where the gears used to be...then you're only left with the existing difficult task of mating the output shaft to the input shaft...


As shown in the video posted by electro wrks about the F-450 conversion, one approach to trimming away excess is to not do it, but to instead use an enormous adapter plate to match the entire intact motor side of the transaxle housing. This also addresses sealing the mating face, since it results in a simple flat sealing surface.

That F-450 conversion also addresses mating shafts, with what may be a custom shaft splined for the motor on one end (replacing the Tesla transaxle input shaft) and the reduction gearbox they're using on the other end. Their reduction box is designed to accept the male splined output shaft of a transmission, so this custom shaft is practical to build (being male on both ends).

A more extreme approach would be to remove that transaxle housing side, which is also the motor end housing, and build a custom replacement of a more suitable (compact) shape.


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## retrEVnoc (Mar 23, 2019)

greg's video series on the F450 conversion is excellent-- very informative. He uses some pricey, but off-the-shelf parts (magnum crawl box by Offroad Design coupled with I think an Atlas transfer case) combined with some custom parts to send power from the tesla motor straight to a 4wd transfer case, circumventing Tesla's gear reduction.

Sam with the Audi conversion of youtube fame also did it, with a similarly custom gear reduction setup, albeit less detailed documentation than greg's truck project.

The beauty of the Tesla drive unit is the integration... integrated cooling, no 3-phase wiring. Splitting it up may well cost you just as much as a different AC system in the end due to the retrofitting needed.


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## electro wrks (Mar 5, 2012)

One potential problem with the F450 conversion could be the early Tesla induction motor(if that's what's being used) overheating. If the truck is used for towing and hauling, as they often are, and the motor run in high enough power output, they may encounter the same problem racers have seen after a lap or 2 at speed. That is the motor's rotor overheating and the controller dropping the power output. From experience, it seems this is less of a problem with the newer, interior magnet permanent magnet(did I get that right?) motors from Tesla. 

I forget what Teslas use this motor(some use both kinds!). brian and others will know this detail, the motor location(front or rear), and their power outputs.


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## brian_ (Feb 7, 2017)

electro wrks said:


> One potential problem with the F450 conversion could be the early Tesla induction motor(if that's what's being used) overheating. If the truck is used for towing and hauling, as they often are, and the motor run in high enough power output, they may encounter the same problem racers have seen after a lap or 2 at speed. That is the motor's rotor overheating and the controller dropping the power output. From experience, it seems this is less of a problem with the newer, interior magnet permanent magnet(did I get that right?) motors from Tesla.


I think that's an excellent point: even if peak power capability is suitable, the motor needs to be able to handle what the vehicle needs continuously. Two motors (for front and rear) would be more appropriate, and would eliminate the need for the transfer case.

Yes, this is an induction motor, presumably the "large" Model S/X motor.



electro wrks said:


> I forget what Teslas use this motor(some use both kinds!). brian and others will know this detail, the motor location(front or rear), and their power outputs.


The original Roadster, Model S, and Model X use only induction motors. The Roadster motor is now irrelevant. The Model S and X use the same motors: 

RWD: one large motor at the rear
AWD (normal): a small motor at the front and another small motor at the rear
AWD "Performance": a small motor at the front and a large motor at the rear
All "small" motors are the same, but the front and rear transaxles are a bit different; all "large" motors are the same (including the same transaxle). The large motor seems to be particularly prone to cooling issues; the large and small motors (with their associated transaxle and inverter) have different cooling system designs.

For power output, I just look at the list someone assembled in Wikipedia.

The Model 3 uses a permanent magnet motor at the rear, but apparently the front motor of AWD Model 3 is an induction motor, possibly related to the small Model S/X AWD motor.


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