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Tesla Motors

Tesla Motors

Tesla Motors

(OP)
Just out of curiosity is there anything special about the motors in a Tesla automobile. I know they are known for their lightning acceleration.
What type of motor?
3 Phase or more?
How many Poles?
Rev range?
Voltage?
Horsepower?

Any other interesting details on the drive system?

My SIL is very interested in these cars, I want to impress his socks off LOL
Thanks
Roy

RE: Tesla Motors

Roy, wouldn't you gain more accurate, viable information by simply writing directly to the company?

Your "SIL" would be more impressed with that information, (don't 'cha think?) than any tid-bits you gained from an Internet forum.

There's nothing to be embarrassed about in writing directly to a company.

Try it!

John : )

RE: Tesla Motors

A lot can be found by simple searches. I'll start you off:

It's a 3-phase, 4-pole AC induction motor driven from an inverter using field-oriented control.

RE: Tesla Motors

Search this site. Tesla specs may have been discussed already.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Tesla Motors

The motor is actively cooled. So is the inverter.

RE: Tesla Motors

I believe the new Model 3s are now using a 3 phase PMAC motor and inverter drive. Higher power density, meaning less weight per HP.


" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

RE: Tesla Motors

jraef:

You're right! While Tesla has been very quiet about the change, others ferreted it out:

https://www.edmunds.com/car-news/auto-industry/201...

I'm surprised. (Not at you being right...) While PM AC motors are smaller and lighter, and a little more efficient, they are also significantly more expensive, which is strange to me when it seems that the big thing for the Model 3 was to get the cost down enough to be a mass-market car. Also, it is much more difficult to vary the field strength in a PM motor enough to do away with a mechanical transmission while keeping the necessary torque/speed combinations. I don't know what Tesla has done here.

RE: Tesla Motors

The motors are less special than the control system. You can run any electric motor at any power output provided the time period at that power output is short enough. I would guess that the continuous rating of the motors in the Tesla are much less than 762 horsepower. Water cooling does help, though. What makes Tesla motors unique is a control system that carefully controls current to allow the motors to operate at very high power output for controlled periods of time without damage from overheating.

RE: Tesla Motors

Good point CS. I wonder why they'd bother even with 4 motors in the model 3.

Keith Cress
kcress - http://www.flaminsystems.com

RE: Tesla Motors

(OP)
Thank-you gentlemen for the information, I did google Tesla Motors of course and got some conflicting information but if I want the real oil on motors I will always come here.
Besides which it's an interesting topic don't you think?

RE: Tesla Motors

I also found it strange that Tesla went into PM motors. Yes, they have somewhat smaller weight/size and bit better efficiency compared to induction motor, but well designed induction motor with squirrel-cage is not bad either.

I think the biggest problem with PM motors is that they are highly sensitive to rare-earth prices, which are into large degree defined by Chinese politics (as over 90% of the Neodymium for example comes from China). There was interesting article on Bloomberg (although the focus was on batteries):

https://www.bloomberg.com/graphics/2018-cobalt-bat...

According to this, price of Cobalt has increased 3 times since Tesla 3 was announced (I'm not sure though is Tesla 3 using Neodymium or Cobalt magnets). Also price of Neodymium has increased significantly during las 12 months

By the way, here is an interview of Tesla's chief motor engineer

https://chargedevs.com/features/teslas-chief-motor...

RE: Tesla Motors

For a supposedly mass produced cars, why would one need 762 HP?

Muthu
www.edison.co.in

RE: Tesla Motors

Marketing.

RE: Tesla Motors

Peak short time HP. The maximum RMS HP will be much lower.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Tesla Motors

The model 3 cars have one rear wheel drive motor rated 258HP per EPA filings. The 4 motors concept is their newly announced Semi Truck, which will use 4 of the same motors used for the Model 3, one on each wheel (making it, by the way, 4WD). I haven't heard the HP number yet, but they may be using different gearing to get more torque at the wheels, which may explain the math differential. Isn't vehicle "HP" measured at the wheels?

Someone spotted a prototype on the road yesterday in a town near by...
https://www.teslarati.com/tesla-semi-spotted-publi...


" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

RE: Tesla Motors

258 HP = 192 kW. The car has roughly a 65 kWh battery pack. Full power would run it flat in less than 20 minutes and that's assuming the whole deal is 100% efficient.

The Model S P100D situation is even sillier. 762 HP = 568 kW. It would run the 100 kWh battery pack flat in 10 minutes! Granted, this would probably involve going 300 km/h or more if the rest of the vehicle would be up to the task. Range at top speed ... maybe 50 km?

All of the Tesla cars have a restricted top speed. There are plenty of reasons. I'm sure their one-speed gearing has the motor hitting its rated max rpm before it actually runs out of power. Protection from idiots is another factor, and it's at least in part because the motors and drive units and batteries are not capable of maximum power output continuously, and also to ensure that the range does not become laughably short.

It's pretty common to have a certain "continuous" rating, and a bigger "intermittent" rating. It's no different here. Combustion engines are not immune to this, either. Top-fuel drag racing engines make thousands of horsepower but only for a few seconds at a time.

RE: Tesla Motors

On that size of truck it would be called tandem drive, not four wheel drive, or 6x4 to differentiate from 6x6 when there is a mixed fleet.

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Tesla Motors

You have to remember that in a car, the motor only consumes energy when accelerating, coasting costs nothing, then recaptures energy when decelerating to recharge the batteries. The only net drain is from the losses through the system.

Bill, makes sense. Not used to there being 6 wheels...


" We are all here on earth to help others; what on earth the others are here for I don't know." -- W. H. Auden

RE: Tesla Motors

Power for aero drag is a velocity cubed function.

RE: Tesla Motors

There's nothing really special about what Tesla does.

The drivetrain is designed to target the 0-60mph acceleration range. The acceleration drops off rather quickly when taken above what is legal anywhere in the US. If you watch them in the 1/4 mile they can get a hell of a jump off the line and still get run down at the top end.

They put a lot of battery into the car to get the long range.

RE: Tesla Motors

And remember with the "buried magnet" design they can run WAY into field weakening high speed; The common delco PMAC EV motor runs 3-4-5-10 times higher than base speed.

www.KilroyWasHere<dot>com

RE: Tesla Motors

"Peak short time HP. The maximum RMS HP will be much lower."

As long as I can remember All of Sears powered equipment, electric and gasoline, employed "interesting" power ratings.

Similar to "HP at the brochure," as I think Car and Driver, or Road and Track once said.

RE: Tesla Motors

Tmoose - yes. There was an air compressor class action suit over the "peak HP" ratings which resulted in their ratings being changed. Small engine powered equipment generally has cc but no HP ratings anymore for similar reasons.

RE: Tesla Motors

I received $ 95.00 in class action suit against small engine mfgr used in my John Deere lawn tractor: 26 HP in 1' cube space! Must have been that overhead cam design...

Here is the spec on the Delphi EV PMAC motor I had in my equinox conversion. Check out the field weakening area 1600 - 10,300rpm! Used resolver feedback for the Rinehart drive. With the liquid cooling, I suspect the HPs Tesla shows are close to continuous; you just can't use them for long due to battery capacity.

www.KilroyWasHere<dot>com

RE: Tesla Motors

I knew a small engine repair instructor.
Whenever the subject of small engine HP came up he would always say;
"The first liar doesn't stand a chance!"

Bill
--------------------
"Why not the best?"
Jimmy Carter

RE: Tesla Motors

I am surprised that on a truck they wouldn't go to wheel motors. Zero drivetrain, the hub is the motor.
This is how heavy haul (mine trucks) equipment is built.
Not desirable in a car since it increases un-sprung weight and has a negative impact on handling, but in a truck that isn't an issue. And it keeps the part count down.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

RE: Tesla Motors

I suspect they wanted to make use of existing parts to keep the cost down, and that means using off-the-shelf (from the trucking industry) wheels, hubs, brake drums, air brake actuation mechanisms etc., and off-the-shelf (from Tesla) motors, which require using a gear-reducer to get into an appropriate torque and RPM range.

Mining trucks don't have to pass the encyclopaedia of DOT and NHTSA regulations, either. Over-the-road trucks do, and there are a fair number of "thou shalt do it this way" requirements in there.

RE: Tesla Motors

There are many pros and cons to in-wheel motors. Obviously more cons than pros or it would be the way it is done. Companies I work with daily make in-motor size PMAC motors; it certainly sounds sexy but absolutely would not be my first choice with all the 'cons.'

www.KilroyWasHere<dot>com

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