The motors found in the model S P90D make a ton of hp and rev to like 14,000rpm. Is there anything special about the way these motors are made vs a typical induction motor you’d find in a factory? I know they are water-cooled and they use a variable frequency drive to constantly maintain torque. I’m assuming better bearings and they are wound differently. Any special exotic metals used? How about the thickness of the laminations?
The Tesla motors are assembled with extra adjectives. They’re not particularly more hi-tech than any other electric vehicle motor. In fact I could guess they’re not current leading-edge design because Tesla may be the one EV manufacturer the makes enough vehicles to concerned about manufacturability and dealer service.
They don’t use any exotic materials or anything. They have a fairly high power density as far as these things go–in part, due to a decent liquid cooling system, and in part because they can get away with a low duty cycle. The motor isn’t rated to put out ~400 hp indefinitely like an industrial motor might.
Mainly, it’s a good motor because it’s designed for the application. An off-the-shelf motor wouldn’t be as good not because Tesla has better tech, but because the performance of an electric motor depends on the compromises made in its design, and matching those compromises with the demands of an electric vehicle produces a good product.
Electric motors put out all of their torque on startup. Tesla built a sports car that takes advantage of that attribute. Previous efforts for EV’s were more focused on miles driven.
Elon Musk recognized the performance qualities of electric motors and filled a niche in the car market. The “Ludicrous Mode” option for his Model S is actually faster than the Dodge Charger Hell Cat in the quarter mile. And that’s saying something. The Hell Cat will probably blow by it in the half mile but who drives 150 mph on the street?
They’re just polyphase AC induction motors, as you say. Unlike the one in your fridge or air conditioner, they’re better suited to work over a wider range of supply frequencies while most garden variety induction motors are intended to work at 50/60 Hz supply.
Yeah, motors with a fixed RPM don’t work so well for vehicles. So before the electronics to deliver variable frequency AC at sufficient power became available electric vehicles used DC motors, which either need big permanent magnets or a way to provide electricity to a moving part, which you both really don’t want if you can avoid it.
The newly-announced Tesla P100D is being advertised as the quickest (0-60mph in 2.5sec) production car ever built. The 918 Spyder and LaFerrari are still quicker in this category, but both are million dollar cars.
Yep. Not only have they been around for quite some time, but they are very common in industrial applications, and VFDs quite routinely control motors a lot bigger and more powerful than the motor in a Tesla. The Tesla motor is somewhere around a couple hundred kilowatts. They have VFDs controlling motor/generators in hydroelectric energy storage facilities that operate well up into the megawatt range.
It wouldn’t surprise me if they used an off the shelf VFD in the Tesla, though they may have rolled their own just so that they can get some extra cooling into the thing.
As far as I know they have been around since the 1970s. Don’t forget that electric trains have been around for a century, so variable frequency electric motors are still relatively new on that scale.
The 568 kW of the Tesla S is insane for a car that weighs about two tons. The older trams/streetcars that are in service here in The Hague weigh about 38 tons and only use 360 kW. I believe the electric motor in a Prius is 27 kW.