Drive motor durability

I've been researching the durability of the Tesla electric drive motor but couldn't find any information. Does anyone know or have any idea, in terms of how many miles, is the electric motor rated at? A typical ICE motor I think is rated at 100K - 200K miles, maybe more?

Tesla has stated it should last the life of the car. AC induction motors only have one moving part, and their use in industrial applications have shown them to be very durable.

They are not under the extreme heat, friction and pressures you encounter with ICE engines that require continuous maintenance to keep them going.

AC induction motors have been used in industry for a long time. They are installed, turned on and run 24/7 for many years afterwards. Shouldn't be am issue.

I'm wondering if the constant acceleration/deceleration, start/stop, etc. have any negative affect on AC induction motors.

I have never heard of an engine being "rated" for a given amount of miles.

What does wear out in an ICE is the compression and oil rings on the pistons, and the valve train. Since the MS doesn't have any of that, there really isn't anything to wear out.

Some have had these units replaced and it is understandable that some may go bad but I think they need to be able to take it apart and fix or replace the individual main components rather than necessitating the $15K repair bill to replace the entire drive unit that a form member recently had to pay because his car was out of warranty.

Has the MS been out long enough that any cars should be out of the standard 4 year warranty?

A little unseemly but I relate the Tesla to the motor in our refrigerator; that thing has run for 30 years with no maintenance.
Its just the way electric motors are.

Has there actually been a motor replaced due to a failure vs the whole unit due to an issue the inverter? The only way the motor itself would fail would be if one of the 2 bearings came apart.

AC motors are only vulnerable to overheating and ball bearing failure. Tesla manages the heating issue extremely well (better than most industrial service motors) with a liquid cooling system and controlling monitors. I have heard the use the best ceramic bearings available but in any event high quality bearings have great service records as well. It is a simple and powerful electric energy conversion device with only 2 ware points that should last the life of the car!

Most of the drive trains that have been replaced havehad noise issues, not functionality issues. They replace the whole thing because it's a sealed unit. The 15K is the retail cost of repair and not what it costs the company. I wouldn't mind hearing more details of that.

The forum member who posted a while back was charged according to him $15K by Tesla to repair his drive unit that was defective. He apparently lived somewhere where he could not get an extended warranty. There are a bunch of threads floating around about drive unit replacements and I hope they have by now figured out what is causing this and fixed the issue.

He owns a limo company and you apparently cannot get an extended warranty if you are going to use it as a limo. Had something like 75000 miles


This thread is about motor durability.

I have not heard 1 single case of motor gone bad since the day of Roadster to Model S.

Motor is not to be confused with Drive Unit Assembly.

A Drive Unit Assembly houses 3 components:

1) Motor
2) Gearbox
3) Inverter.

Each component failure would give you a different symptom.

If your motor fails, you can floor your accelerator but your car does not move, you only hear the inverter whines.

If your Gearbox fails, you can hear a mechanical breakage, your motor runs but it cannot transfer the torque to the wheels. Your car just coasts with no propulsion.

If your inverter fails, there would be no mechanical noise, your motor does not get enough current from the inverter, it slows down and the accelerator would have no effect.

If there is even a very simple failure anywhere in the Assembly: such as a loose connection, a blown fuse, a defective chip in the inverter, current repair protocol is to drop the whole assembly down and replace it with another one.

This swapping simplifies the repair process for the Service Center and saves you time.

That's why if you complain about the noise coming from the rear, Tesla would be happy to swap the whole thing out for you with no question ask as reported by all affected.

It doesn't matter what is subpar in the Assembly, whether the noise complaint, worn out Gearbox or a loose connection, the Assembly swap is done!

The issue is fixed.

The quoted $15,000 is for a California Limousine Owner Goldie Bhullar.

For some unknown reasons (It's possible that he followed advice from this forum to skip the extended warranty to save money), he did not buy an extended warranty and when it's time to swap the Assembly, he's way over the mileage and could no long buy extended warranty at that time.

For non-commercial owners, you are covered.

Commercial users aren't eligible for the extended warranty.

Just to clarify - the warranty is 4 years or 50,000 miles whatever comes first.

So if you drive 100,000 miles year then you are out of the base warranty in 6 months.

The $15K sounds excessive. Lets say I drive the car for a few years and it's over 50K miles. Then I hear noises coming from the drive assembly. Does that mean I have to shell out $15K to get rid of the noise? Wonder how often does this noise/drive assembluy issue come up?

Compared to an ICE motor, it really never needs replacing. And if it does, it's around $3-$7 for the average car I think.

I can't attest to the validity, but I was told by a Tesla mechanic that the motor has been tested up to 4 million miles and was spec'd to 1 million miles of operation. Obviously, if this extended life testing was actually performed, it was likely in a benign environment. Electric motors are extremely high reliability components - an electric motor in any electric car should easily last the life of the automobile, if built to spec and free of manufacturing or production defects.

Let's also please keep in mind that the Internet amplifies problems. When there is an issue, people generally seek out advice from other owners and post about their problems online. By comparison, hardly any people do the same when they are thrilled with a product and have no issues. So let's maintain some perspective. Just because we are reading about issues here does not mean that this is a widespread problem.

With regard to the highway hum, ballon squeal, and other strange noises... those are not directly related to the motor itself. They most likely have to do with the inverter, the mounting points, or may simply be resonance from the components themselves.

Nissan has gone through similar issues with its motor/inverter, requiring them to redesign the shapes of certain parts as well as the motor mounts to reduce resonant vibrations. New drive unit replacements from Tesla include updated motor mounts. It seems Tesla may have redesigned some items for the same reason as Nissan. Here is an excerpt regarding the Nissan issues:

""The motor produces electromagnetic excitation forces when it generates torque. These electromagnetic forces are transmitted through the structures of the connected parts and resonate with the natural frequencies of the parts they pass through to produce noise. To address this issue, the electromagnetic circuit of the motor was optimized to reduce electromagnetic forces, and the shapes of the parts the forces pass through were also optimized, thereby reducing noise and vibration.

"The geometries of the water jacket and the inverter case were optimized to reduce the radiation noise caused by excitation forces input from the motor. Measures were also taken to prevent PCB-mounted components from falling out due to motor vibration. Specifically, a vibration analysis was conducted on the PCB to identify areas where the stress induced by motor vibration was low. The pattern of mounting components on the PCB was then improved such that heavy components like the electrolytic condenser and others are mounted in areas of low stress. This improved mounting pattern suppresses the level of vibration applied to such components."

I found antoher thread "What's up with Edmunds and drive units" that discusses the current issues with multiple drive unit replacements among many MS owners. Please see that thread.

Electric motors have very long life because of the simple design. Industrial electric motors last tens of years with much heavier use than the ones in the MS. One example from our daily life is those electric pumps we use for aquariums and fish ponds. Those (chaep) pumps can run continuously for many years without any problems.

@johnl972001, may I ask what is the purpose of your research?

After reading the "What's up with Edmunds and drive units" thread, I am now hesitant on purchasing the MS. I don't want to have to shell out $15K - $30K or more after my warranty expires to replace the drive unit(s).

Unless Tesla comes out with a definite fix, I really don't want to to take that risk.

@ johnl972001,

I think you've made a good decision. Please make sure to come back and let us know when you do decide to buy, that way the rest of us will know when Tesla comes out with a definite fix to what is a non-existent problem for the vast majority of Model S owners.

By that time Tesla might even have fixed the non-existent seat and interior quality problems too.

@carlk: Because when it comes to these things the only opinion that matters is yours and the seat quality is so high that it is the pinnacle of perfection in the automotive world :)

This thread would be better titled "Fishing..."

$15k sounds like a one-off price for this poor guy who happened to be at the bleeding edge. Tesla will have to come up with a better price and repair system by the time the large numbers of cars are out of warranty. This should cost less than replacing a gasoline engine, not 3 times more.

Because ALL Tesla are still under warranty, no owner has been charged a dime let alone 15K. As Amped said, non-existent problem.

Service life on a motor of this type should be about a million miles. Other normal car parts on any auto will be EOL by then.

@jbunn. Except for the limo company owner.

This taxi driver went beyond 50K miles without an extended warranty, since it's not available to commercial enterprises. Hence, the reality.

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