LEAF Performance tuning

[Dala]

So much speculation in this thread :lol:

The 2013-2017 LEAF EM57 motor has a stock rpm limit of 10,390. This was increased to 11,330rpm on the 2019 e+ LEAF. This is a hard limit when using the stock inverters.

However, by switching to an aftermarket inverter, you can override this limit. People on the openinverter forum has taken the EM57 to 15,000rpm without issues. However, there is a physical limit on these motors, this is what can happen when you accidentally push >20,000rpm

 

[alozzy]

20000 rpm is insane, it's amazing it held together that well.

 

[LeftieBiker]

Looks like a DC motor that lit up its brushes.

 

[nlspace]

Operating above the 1st rotordynamic bending mode ?

 

[goldbrick]

Yikes. Did the magnets on the rotor crack? Or are they supposed to have the offset between the 2 halves?

I wish I had the time to play with this type of stuff, looks like fun.

 

[LeftieBiker]

However, by switching to an aftermarket inverter, you can override this limit. People on the openinverter forum has taken the EM57 to 15,000rpm without issues. However, there is a physical limit on these motors, this is what can happen when you accidentally push >20,000rpm

What speed does 15k RPM translate to, assuming stock gearing and tire size? Is it really about 130MPH?

 

[alozzy]

Based solely on a linear math calculation...

(15000/11330) * 90 mph = 119 mph

 

[knightmb]

So a Leaf Plus would be ...
(15000 x 100 / 11330), 132 MPH, interesting, but would the tires be able to handle it? :lol:
Also, is the Leaf cooling system able to keep the motor cool pushing that extra power for longer I wonder? :twisted:

 

[alozzy]

So a Leaf Plus would be ...
(15000 x 100 / 11330), 132 MPH, interesting, but would the tires be able to handle it? :lol:
Also, is the Leaf cooling system able to keep the motor cool pushing that extra power for longer I wonder? :twisted:

Unless you are on a track, running at 130 mph for any length of time is unlikely anyways - that kind of speed usually gets the attention of the cops

 

[DougWantsALeaf]

Could you change the gear ratio combined with upping rpms to significantly boost top speed? (with slower 0-60)

 

[GerryAZ]

So a Leaf Plus would be ...
(15000 x 100 / 11330), 132 MPH, interesting, but would the tires be able to handle it? :lol:
Also, is the Leaf cooling system able to keep the motor cool pushing that extra power for longer I wonder? :twisted:

The tires should be OK since OEM Michelins, on Plus models at least, were "V" rated which should be 149 mi/hr maximum (assuming normal load and inflation). Cooling of inverter and motor could be an issue with sustained power output that high

Thanks to Dala for showing what happens when the permanent magnets move enough to hit the stator core. It is good to know that Nissan's RPM limit is conservative.

 

[LeftieBiker]

Could you change the gear ratio combined with upping rpms to significantly boost top speed? (with slower 0-60)

That's the $64k question. It would require that either there be another gear set available that provides a significantly higher (numerically lower) final drive ratio, or that someone manufacture such a set. The clearances inside the gear case would set a limit on the size of the larger gear.

 

[LeftieBiker]

Thanks to Dala for showing what happens when the permanent magnets move enough to hit the stator core.

So, did one or both bearings start to fail, allowing the shaft to wobble enough to hit the stator core, or did the magnets start to come loose...?

 

[goldbrick]

Maybe the rotor got so hot it expanded until it made contact with the stator.

 

[goldbrick]

That's an interesting motor. I'm used to 8-pole/12 slot or 12-pole/9 slot. There must be 40+ slots on that one and I have no idea how many poles in the magnets.

 

[GerryAZ]

Thanks to Dala for showing what happens when the permanent magnets move enough to hit the stator core.

So, did one or both bearings start to fail, allowing the shaft to wobble enough to hit the stator core, or did the magnets start to come loose...?

It looks to me like the magnets broke in the middle and hit the stator due to centrifugal force from high RPM. I assume the magnets are secured at both ends.

 

[alozzy]

That's an interesting motor. I'm used to 8-pole/12 slot or 12-pole/9 slot. There must be 40+ slots on that one and I have no idea how many poles in the magnets.

Plenty of details here on the EM57 motor design:

https://www.marklines.com/en/report_all/rep1779_201811

 

[GerryAZ]

Thanks to Dala for showing what happens when the permanent magnets move enough to hit the stator core.

So, did one or both bearings start to fail, allowing the shaft to wobble enough to hit the stator core, or did the magnets start to come loose...?

It looks to me like the magnets broke in the middle and hit the stator due to centrifugal force from high RPM. I assume the magnets are secured at both ends.

After viewing the link Alozzy posted, it looks like the laminated magnet steel on the rotor separated at the joint in the middle and hit the stator due to centrifugal force.

 

[LeftieBiker]

I understand the explanation for why they used that stepped rotor design, but that certainly is the failure point for this motor at super-high RPM.

 

[Dala]

Jim (Turbo3), Leafspy creator, just got back to me regarding adding resolver offset writing natively to Leafspy. I'll test the next build, and make a howto video on how to use it. This will save so much time, money and effort when it comes to motor/inverter/performance tinkering with LEAF bits