Electric motor maximum rpm

[JJAZ]

Has anyone noticed that the electric motor rpm display goes red at 8500rpm and doesn’t go back to white until it goes back under 8200rpm? Why is this? I thought the max motor rpm is 10000rpm, will running the motor at above 8500prm do any damage? There’s nothing in the handbook.

 

[Jomarkh]

What mph is 8500rpm equivalent to

 

[JJAZ]

I’m not sure, I had the motor speed screen on the dashboard.

 

[Gomev]

I’m not sure, I had the motor speed screen on the dashboard.

You must have been spinning the motor at 8500rpm to make it go red, that must be a reasonable old speed since you can't 'rev' it in neutral. .

 

[JJAZ]

A downhill stretch of the autobahn ?

 

[Kithmo]

Has anyone noticed that the electric motor rpm display goes red at 8500rpm and doesn’t go back to white until it goes back under 8200rpm? Why is this? I thought the max motor rpm is 10000rpm, will running the motor at above 8500prm do any damage? There’s nothing in the handbook.

Does it go higher if the battery is fully charged ?

 

[JJAZ]

I don’t think so, the battery state of charge should have no effect on motor rpm, it’s only throttle position and road speed.

 

[Kithmo]

I don’t think so, the battery state of charge should have no effect on motor rpm, it’s only throttle position and road speed.

Turtle mode slows the motor when the battery is low.
Also some people have reported not getting full power when the SOC is low, before turtle mode.

 

[Coulomb]

the electric motor rpm display goes red at 8500rpm and doesn’t go back to white until it goes back under 8200rpm? Why is this?

I can only think that some part of the motor can't maintain that speed continuously, though it can do 10,000 r/min for some time, perhaps half an hour. Maybe it's the bearings.

But I'd say it is some other variable, probably motor temperature, that is higher at higher motor speeds, therefore higher vehicle speeds, therefore higher motor power. Power to maintain a certain velocity (speed) is proportional to the square of the velocity at higher speeds.

Maybe they aren't measuring the motor temperature directly with a sensor, and just use motor speed as a proxy for motor load and therefore (over time) motor temperature. It would sure be nice to have access to a service manual that could answer questions like these.

 

[chromeskull]

What mph is 8500rpm equivalent to

Approximately 85mph. The gearbox ratio is around 100/1.

Also to note, if you sit in the red for an extended time, it will take longer for it to reset to white at a lower speed. I guess it's to allow it to safely cool.

 

[Coulomb]

The gearbox ratio is around 100/1.

Err, you mean approximately 100 r/min (motor speed) per mi/h (vehicle speed). I calculate the overall ratio (motor speed divided by wheel speed) to be 7.58, based on 8500 r/min, 85.0 mi/h, and a tyre size of 215/50 R17 (diameter 2.032 m). That's what is usually meant by "gearbox ratio".

That's as approximate as your figures, of course, but it's interesting for the nerds amongst us. The Nissan Leaf for example (since 2013) uses 8.19:1. So its motor would be spinning about 7% faster at the same vehicle speed.

Thanks for your figures.

[ Edit: 7% slower -> 7% faster. Duh. ]

 

[chromeskull]

Err, you mean approximately 100 r/min (motor speed) per mi/h (vehicle speed).

Yes, thank you for clarifying and expanding on it.