Number of revolutions your motor has made.

[timk225]

I was thinking today of how many times my Model 3's motor has spun around. For Teslas, this is a simple calculation. With no clutch or torque converter, and no idling in traffic, the only real variable is tire size / number of tire revolutions per mile, and the manufacturer websites list this.

For my Primacy MXM4 235-45-18 tires, the number is 790 revs per mile. This, times the 9:1 gear reduction equals 7110 motor revs per mile, times your total number of miles, and that's it!

So it is ((tire revs/mile X 9) X total miles driven).

My 3 has 54,876 miles, so my motor rev count is 390 million, 168 thousand, 360 turns.

For 25,000 miles, it is 177,750,000.
For 50,000 miles, it is 355,500,000
For 75000 miles, it is 533,250,000
For 100,000 miles, it is 711,000,000 turns.

The 19 and 20 inch wheels would make slightly different numbers due to tire size difference, but not a huge change.

So yes, this means that at 60 mph the motor is turning 7110 rpm. At 80 mph, 9480 rpms. If I top out my Model 3 at its 140 mph limit, that is 16,590 motor rpms at top speed.

 

[ebmcs03]

So what’s the magic number when the motor blows?

 

[timk225]

I'll let you know when it happens.

 

[ranss12]

I did the same calculation for my airplane - how many times does the propeller turn between recommended engine overhauls. 1800 hours time between overhauls x 2250 average rpm x 60 min/hour = 243,000,000 revolutions between overhauls. During that time the plane would have flown approx. 216,000 miles and the prop rotated about 1,125 times per mile.
To bring this back to Teslas, their motors can easily last longer than 1.5 billion turns (200,000 miles), about 6 times more than high reliability ICE airplane engines, although they both cover about the same distance ~200,000 miles.

 

[brkaus]

It’s nothing compared to industrial motors running 24 x 7 x 365

 

[SSedan]

I did the same calculation for my airplane - how many times does the propeller turn between recommended engine overhauls. 1800 hours time between overhauls x 2250 average rpm x 60 min/hour = 243,000,000 revolutions between overhauls. During that time the plane would have flown approx. 216,000 miles and the prop rotated about 1,125 times per mile.
To bring this back to Teslas, their motors can easily last longer than 1.5 billion turns (200,000 miles), about 6 times more than high reliability ICE airplane engines, although they both cover about the same distance ~200,000 miles.

Not like airplane parts are replaced/overhauled preventatively we just let them go till they fail and and we pull to the side of the road and call a tow truck.

 

[one2many]

Ok, I will bite, my washing machine does washing, and Beta spin dry. I have never
heard of one of these failing, motor anyway. For the math inclined, what is the MTF
for one of these motors? There has been some nasty stuff put in them, heavy as well.

 

[SomeJoe7777]

The actual motor elements, which are the copper windings and the laminated sheet steel of the rotor, will generally last forever unless overheated repeatedly or exposed to some corrosive environment

The shaft bearings require periodic replacement, they are a wear item. But the time between replacements is long.

When I served in the US Navy, we had turbine generators in the engine room that were 35 years old, and the windings were still in perfect condition. The only periodic maintenance required on the generator end was bearing lubrication, brush replacement, and slip ring maintenance. The motors in the Teslas have no brushes or slip rings, so the only thing left is bearings.

 

[ebmcs03]

It’s nothing compared to industrial motors running 24 x 7 x 365

But we don’t have industrial built motors.

 

[ebmcs03]

The actual motor elements, which are the copper windings and the laminated sheet steel of the rotor, will generally last forever unless overheated repeatedly or exposed to some corrosive environment

The shaft bearings require periodic replacement, they are a wear item. But the time between replacements is long.

When I served in the US Navy, we had turbine generators in the engine room that were 35 years old, and the windings were still in perfect condition. The only periodic maintenance required on the generator end was bearing lubrication, brush replacement, and slip ring maintenance. The motors in the Teslas have no brushes or slip rings, so the only thing left is bearings.

Oh no. But how do i lubricate the bearings in the motor?

 

[TT97]

I was thinking today of how many times my Model 3's motor has spun around. For Teslas, this is a simple calculation. With no clutch or torque converter, and no idling in traffic, the only real variable is tire size / number of tire revolutions per mile, and the manufacturer websites list this.

For my Primacy MXM4 235-45-18 tires, the number is 790 revs per mile. This, times the 9:1 gear reduction equals 7110 motor revs per mile, times your total number of miles, and that's it!

So it is ((tire revs/mile X 9) X total miles driven).

My 3 has 54,876 miles, so my motor rev count is 390 million, 168 thousand, 360 turns.

For 25,000 miles, it is 177,750,000.
For 50,000 miles, it is 355,500,000
For 75000 miles, it is 533,250,000
For 100,000 miles, it is 711,000,000 turns.

The 19 and 20 inch wheels would make slightly different numbers due to tire size difference, but not a huge change.

So yes, this means that at 60 mph the motor is turning 7110 rpm. At 80 mph, 9480 rpms. If I top out my Model 3 at its 140 mph limit, that is 16,590 motor rpms at top speed.

You forgot to count the revolutions when reversing!

 

[ebmcs03]

You forgot to count the revolutions when reversing!

That subtracts from the total count right?

 

[timk225]

Oh no. But how do i lubricate the bearings in the motor?

I am guessing they get splash lubrication from the differential oil. That's something I've never known. Does the Model 3 motor armature run "dry" with no oil near it ever, or is there oil flying around in there? The bearings have got to have oil to them one way or another.

 

[SomeJoe7777]

I am guessing they get splash lubrication from the differential oil. That's something I've never known. Does the Model 3 motor armature run "dry" with no oil near it ever, or is there oil flying around in there? The bearings have got to have oil to them one way or another.

If I remember correctly from discussions several years ago regarding the Model S motor, yes the bearings are lubricated by the differential oil from the reduction gear box.

The rotor of the motor runs dry, there is no lubrication in contact with the surfaces of the rotor or stator. I believe there is a clever cooling system for the rotor where coolant travels through the shaft, but not on the outside.