Tesla

Nowadays the hotter cars have a _lot_ of software for that sort of thing. They even dial back the maximum torque if you aren't steering straight ahead, and that's with gas engines. I'd be very surprised if Tesla didn't do the same thing.

Cheers

Phil Hobbs

Wheel motors mounted outboard (like disc brakes) contribute a lot of unsprung weight that makes the handling squirrelly on rough roads. If you mount them inboard (connected with half-shafts like a transaxle), they take up a lot of cab space. So mounting the motors like engines makes a lot of sense.

Besides, the maximum torque you can get from a motor goes as its volume, so gears are a win for electric cars. (Maximum current density and maximum B field are more or less fixed, so the twisting force goes as the surface area, and the lever arm goes as the radius.)

Cheers

Phil Hobbs

you can't spend 10 seconds on google?

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erter control vector - it has the same efficiency as when used as a motor

s bad at maximum slip, but it will not be operated at that point, since the n you would be braking a lot harder than the maximum acceleration. It has a acceleration 0-100km/h in something like 3 seconds, and how often do you b reak that hard?

current by operating at a large slip. Modern synchronous motors have other options. I does help if you can control the frequency of the AC you are ge nerating, which is easier now than it was in 1900.

We were discussing induction motors, and if you want to refer the torque to the current or the slip is a matter of semantics. They are interrelated

For PM motors (syncronous motors), the optimum is 90 degrees between the st ator vector and the rotor vector

Cheers

Klaus

I have driven several different electric cars, also the Tesla Roadster. It handles like a gasoline sports car, in fact better IMHO. It's digital control, so the determine the ramp-up of current (torque) and they ease off the acceleration with SW

Cheers

Klaus

I guess they get that huge acceleration by massively over-slipping the induction motor, and counting on the wheelie weight shift to the rear wheels, fuel-dragster style. For people who like to drive in very short burst of high Gs, and don't have wives as passengers.

That is correct. For nearly everyone with a Tesla, is is not their only vehicle, it is their commute vehicle and is used for only shorter trips. For long road trips they have an SUV or minivan.

Plug-In hybrids are popular because they combine sufficient range for most commutes on electricity, enabling the use of the HOV lane, but can also be used for longer trips.

Take away HOV lane access, or no congestion charge for electrics, and almost no one would buy electric cars unless petrol or diesel costs more than electricity.

Nikolai Tesla was one of the inventors of the induction motor.

Cranking up the current until the motors overheat, I expect.

Cheers

Phil Hobbs

Tesla's "ludicrous" mode is just about 1 g. The motor won't heat up much in 8 seconds.

Well, they must be dumping a good 100 kW into the poor thing, so it might get toasty pretty fast.

Cheers

Phil Hobbs

I think you are generalizing.

If I should do the same with my daily trip of 55km to work in which I see an increasing number of Tesla S85, I would say they are extensively used for commuting

We do not have HOV lanes and they are ever still increasing the marked share

Cheers

Klaus

It's a 33kW motor. So I guess 66kW total.

Our motors, also PM 3 phase motors, are rated for 15% overload continously. So running it at 50% overload won't heat it up dangerously

Cheers

Klaus

Probably no hotter than the batteries...

Is free charging common? Around here a bunch of companies offer no-cost charging, but it's becoming less common and when they go to paid charging the rates exceed what it costs to charge at home. Electricity rates are very high in my area unless you go to time-of-use rates, and then they are just moderately high. I have one acquaintance who drives a Tesla and still gets free charging because he works at Tesla.

We have a Prius Plug-In. It's what SWMBO wanted. Personally I don't care for it at all for several reasons. 1. No spare tire, batteries fill that space. I bought a spare tire and the tools but to carry it along takes up a good deal of cargo space. 2. Terrible rear visibility. This is not just a Plug-In Prius issue, it's an issue on all Priuses. 3. Lots of road noise, not good for long trips. 4. Poor acceleration.

We also have a Camry hybrid which is a pretty good car. Very quiet, excellent acceleration, and comfortable on long trips as long as you pack light because the trunk is small due to the batteries. About 40MPG on average which is pretty good for vehicle of that size.

If only we could get some of the European models of vehicles with diesel engines and manual transmissions.

My friend who works at Tesla said they had a motor on an engine stand and they dried dumping 2x the rated design power into it. It flew off the engine stand and across the lab. But it didn't break.

It's still true at low speed. At low speeds induction moiors have low efficiency too.

less than a combustion engine at the same power output

-Lasse

Sure, but (a) the thermal mass of a gas engine is much higher than that of just the motor windings, and (b) the gas engine is water cooled.

Cheers

Phil Hobbs