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[grmarks]

So I was just playing with some numbers today on my 2015 SR. By measuring the circumference of the rear wheel I calculated the RPM of the motor at 160 km/h, which is about 6,000 rpm.
The lightning motor does 10,000 rpm, if the Zero motor was spun at that speed the bike would be doing 268 km/h. Don't know that the motor could handle the heat if the voltage was raised enough to get that rpm (working from the adage - voltage = rpm, amps = torque) or if the sevcon could handle extra voltage.
The new IPM motor is more efficient at higher revs in general terms, so will we see a voltage increase in the battery pack in future to give a higher top speed? A side affect would be better compatibility for fast charging infrastructure. 
Even an extra 2,000 rpm would give you 213 km/h.
   

[Doctorbass]

The Zero use a motor that is wound for torque to get great acceleration. Usually these motor have lower speed per volt so to compensate and get the advantages of torque AND high speed the sevcon that control the motor use Field weakening to  increase motor rpm at a cost of efficiency loss by playing with timing of the motor/controller. .

The sevcon can safely work to 116V but they can go as high as 125v if i remember correctly.

Problem come when you take a look to the torque curve: the torque begin the decrease at about 3000rpm.

To get high speed you need torque corresponding to the required one at the desired speed... if you have the power but not the right torque at the speed you want to acheive it will be impossible. 

If you just  gear it for higher top speed and keep the actual torque curve i doubt you wold reach that speed.

Now come the question: is 50kW enough to fight the wind and all related frictions...

We would need to compare with the equivalent ICE motorcycles....

Here is an interesting graph here and according to it you would need about 200hp ( 150kW)... 3 tome more power than what the actual Sr can do : 

And this graph is  accurate if you compare with the actual top speed of 165kmh  the Zero does and  the 67hp it have.. unless it is limited by the torque...

Doc

[mrwilsn]

Here is an interesting graph here and according to it you would need about 200hp ( 150kW)... 3 tome more power than what the actual Sr can do : 

If you reduce the drag coefficient you will not need as much power to get to higher speeds.  Top speed could be increased by adjusting the gears and making the Zero more aerodynamic.  0-60 times would still be reduced but not as significantly.

[ha4ik]

I think speed is limited by software in Sevcon. In my Zero XU 2013 there is and option screen where I can set up main gear ratio for Sevcon to uderstand correcty the speed. I think same feature shall be in all Zero bikes. So if you cheat there you can see what is real max speed of your bike (by GPS of course).

[grmarks]

The Zero use a motor that is wound for torque to get great acceleration. Usually these motor have lower speed per volt so to compensate and get the advantages of torque AND high speed the sevcon that control the motor use Field weakening to  increase motor rpm at a cost of efficiency loss by playing with timing of the motor/controller.

Not that I understand all the technical stuff but isn't an Interior Permanent Magnet motor less affected by inefficiency at high speed?

[mrwilsn]

The Zero use a motor that is wound for torque to get great acceleration. Usually these motor have lower speed per volt so to compensate and get the advantages of torque AND high speed the sevcon that control the motor use Field weakening to  increase motor rpm at a cost of efficiency loss by playing with timing of the motor/controller.

Not that I understand all the technical stuff but isn't an Interior Permanent Magnet motor less affected by inefficiency at high speed?

I think you are right.  A quick google search reveals this article which gives some pretty good insights into the advantages of IPM over SPM.  The punchline is that IPM motors have 2 major advantages.

1. "In SPM designs, a significant amount of heat is generated in the magnets, which can cause demagnetization. IPM machines with distributed windings typically do not generate a significant amount of heat in the rotor—roughly 90% of the motor losses tend to occur in the stator, which can be easily cooled by heat sinking, oil cooling, or watercooling."

2. "At low speeds, SPM motor and an IPM motor of the same size can generally produce about the same amount torque, or the SPM design may even produce a bit more up until they reach the corner point RPM. At speeds higher than the corner-point RPM, torque from SPM designs drops rapidly. If both of them have a base of 3000 RPM, the SPM motor will probably have zero torque at 5000 RPM whereas the IPM could continue on to 10,000 or 12,000 RPM"

This suggests that the new IPM motor used in the Zero SR is capable of maintaining torque at a much higher RPM than the older generation SPM motor.  Zero reduced the number of teeth on the rear sprocket from 132T to 130T.  This means fewer revolutions to hit top speed but the motor has to put out more torque at low RPM in order to maintain the advertised 0-60 times.  I suspect that the new IPM motor Zero is using is capable of more than how it is being used in the 2016 lineup.  It may require different programming of the controller to get more performance and Zero may need more time to be ready to release the improved performance.  Or it may require a new controller to get more out of the motor.

All the information I can find all seems to suggest that the new IPM motor is not what is limiting top speed in the 2016 Zero SR.  It is more than likely capable of both higher top speed and faster 0-60 times.  The only question is what is the limiting factor.  I'm sure it won't be long after these bikes start to end up in garages before we will find out.

Interior Permanent Magnet Motors Power Traction Motor Applications

[CScalpeL]

I'm having trouble coming to terms with those Dyno run data, Doc.

If the bike is electronically limited to 6000 RPM which corresponds to 160 kph then according to the graph at 80 kph (3000 rpm) we should start experiencing a severe drop in acceleration. That has not been my experience after testing my 0-100 times (I attached a graph that I posted on another thread), wonder what could be the cause of the discrepancy?

If the dyno run is accurate, it would make a strong argument for a gearbox...

[RNM]

For the gearbos weight penalty, I think I would prefer a bigger motor and controller...

[grmarks]

For the gearbos weight penalty, I think I would prefer a bigger motor and controller...

And so does every other electric vehicle manufacturer except the engineers who designed the Brammo

[Doctorbass]

I'm having trouble coming to terms with those Dyno run data, Doc.

If the bike is electronically limited to 6000 RPM which corresponds to 160 kph then according to the graph at 80 kph (3000 rpm) we should start experiencing a severe drop in acceleration. That has not been my experience after testing my 0-100 times (I attached a graph that I posted on another thread), wonder what could be the cause of the discrepancy?

If the dyno run is accurate, it would make a strong argument for a gearbox...

What you dont know is that the 160kmh is not with 6000rpm...  at 6000rpm the wheel spin alot more fast but unloaded.

[Doctorbass]

I just finished making this compare graph between the 2012S and 2014 S SR

It reveal intereting info!