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[NEW2elec]

GaryArt1

In electric it's not the size of the motor that matters it's what you do with it.   

I'm not an expert either but based on a quick double check of the 2017 DS vs DSR range numbers from Zero both bikes had the same range estimates.  The DSR has the 75-7 motor at 70hp while the DS had the 75-5 at around 60hp.  Now if you use the more powerful motor to jump off the line quicker and jump to it's top speed faster and longer then you will have less range because you used more power over all.
Going the same speed on both with the same torque setting should give you the same range.  But that's no fun.  This bike is going for the performance rider so there is a likely real world, real ride range decrease from the same battery for that reason.

Ice bikes have to burn more fuel to move that bigger piston or more pistons of a bigger engine even at idle, which is one of the reasons city mileage is worse for ICE bikes than highway mileage, but with also the same energy loss for going faster and accelerating faster.

[JaimeC]

if you watched the video clip I posted, you'd've seen the motor.

No, I didn't see it, just scrolled back and found it now. Where did you get the video from?
Doesn't make much sense to me to have the fins running around the motor when it's not in the air flow. The previous design (fins running across) is a real cost saver. A continuous extrusion is a lot cheaper than a cast.

Asphalt & Rubber originally posted it on their page, but the video itself is from Zero.  I don't know why Zero doesn't have it on THEIR page though.  I never understood why the cooling fins on the previous motors ran perpendicular to the path of travel as that doesn't seem particularly efficient at promoting airflow.  Making them parallel to the path of travel makes more sense, but then it does cost more to produce.  And who says the motor is outside the airflow?  Don't you think that was a consideration when the bike was designed?  These things are all modeled out on sophisticated CAD/CAM systems before physical mockups are produced and the first prototype spins a wheel.

[NEW2elec]

As for the motor fins.  There was an old live feed from the Zero execs saying the current fin design was used because it was a cheaper manufacturing process but were a little embarrassed when people pointed out how bad the air flow was with that design.

This one should get air moving all around the motor getting more air to more surface area of metal cooling it better.

[Richard230]

As for the motor fins.  There was an old live feed from the Zero execs saying the current fin design was used because it was a cheaper manufacturing process but were a little embarrassed when people pointed out how bad the air flow was with that design.

This one should get air moving all around the motor getting more air to more surface area of metal cooling it better.

The same sort of radial fin arrangement was used on very early ICE motorcycles, but was soon changed to fins that paralleled the air flow, so as to provide more efficient engine cooling when moving. (Perhaps this was not a big concern with ICE motorcycles during the early 1900's.    )  So I would agree that the fin arrangement of the Zero motors likely has a lot more to do with the ease and cost of manufacturing the motor case and less with cooling efficiency.

[Doug S]

My $0.02 on motor fins: When I first saw the "lateral" direction of the fins on the Z-force motors, I was also thinking it's completely wrong, but I could also see that it was a lot simpler extrusion than "longitudinal" fins would have been. Then I realized the motor's not out in the airstream anyhow, and Zero didn't make any cowlings or anything to direct air at the motor, so any airflow it's getting at speed is really just turbulence off of the stuff in front of it, anyhow. It would seem, since Zero did make the change, that longitudinal fins are better than lateral ones, but how much, really?

[BrianTRice@gmail.com]

Producing the same amount of power from a larger motor generally means producing less heat per volume of mass (or the surface area to radiate+conduct it externally). So, the larger size of a 75-10 motor has that going for it even if you don't use the power.

I have no use for additional power (and my regular passenger can easily be jerked around on my DSR if I'm not careful), but maybe this means the motor will last longer and perform better in the heat, which is commendable.

What'd really be a nice trick is if they figured out how to make the motor encoder position sensor more reliable, design-wise, but it'll take some digging later to reveal that properly.

[centra12]

As Zeros' chief electrical engineer who designed the IPM motor said, if a motor produces a certain amount of power then it makes no difference if the voltage is 100V or 400V it produces the same amount of heat in the motor.

That's the greatness bullshit I've ever heard!
What makes the coils of an electric motor get hot? From voltage or the current 

With such a statement, the probability of CCS equals "Zero" 

[Crilly]

If a motor is 80 percent, 20 percent is waste heat.  Two motors running at same power, a big one produces the same heat as a small one.  Same btu’s.  The smaller one gets hotter is all, but same wasted energy.  All wasted energy is heat.

[Curt]

As Zeros' chief electrical engineer who designed the IPM motor said, if a motor produces a certain amount of power then it makes no difference if the voltage is 100V or 400V it produces the same amount of heat in the motor.

That's the greatness bullshit I've ever heard!
What makes the coils of an electric motor get hot? From voltage or the current 

With such a statement, the probability of CCS equals "Zero" 

P_waste = I_motor² R_parasitic
          = (P_motor / V_motor)² R_parasitic
          = P_motor² R_parasitic / V_motor²
          = constant / V_motor²

So I think you are right. To first order, the heat dissipation varies as the inverse square of the motor voltage. Quadrupling the voltage should cut waste heat by an order of magnitude. Just like in transmission lines.

But certainly the Zero engineer was referring to the mechanical power output of the motor as opposed to the waste heat, and in that context was also correct.

[Auriga]

At some point, I think there's a risk to changing too many things at once. We've already got proof they've got a new frame, new motor, new battery case, new dash, and possibly more.

I suspect the increase in motor rotor size will reduce or eliminate the motor heat issue except in extreme conditions, the battery fins will help with charging heat, and traction control will make it all usable.

If they don't increase battery voltage and provide more or equal level 2 charging standard, I'd be pretty happy. For all the hype, DC fast charging doesn't seem nearly as widespread around me, so I'm fine with 6kW+ level 2. Charging any faster than that without thermal management is a recipe for battery destruction.

[caza]

Basically the biggest reason to have DC fast charging has more to do with being competitive with lightning and harley and less to do with an actual need and benefit.

I'll take faster level 2 charging any day over harleys solution of only level 3 and level 1.

[centra12]

As Zeros' chief electrical engineer who designed the IPM motor said, if a motor produces a certain amount of power then it makes no difference if the voltage is 100V or 400V it produces the same amount of heat in the motor.

That's the greatness bullshit I've ever heard!
What makes the coils of an electric motor get hot? From voltage or the current 

With such a statement, the probability of CCS equals "Zero" 

P_waste = I_motor² R_parasitic
          = (P_motor / V_motor)² R_parasitic
          = P_motor² R_parasitic / V_motor²
          = constant / V_motor²

So I think you are right. To first order, the heat dissipation varies as the inverse square of the motor voltage. Quadrupling the voltage should cut waste heat by an order of magnitude. Just like in transmission lines.

But certainly the Zero engineer was referring to the mechanical power output of the motor as opposed to the waste heat, and in that context was also correct.

Idiocy

A good example were the 2012 motorcycles with the update to 75-7
The halved voltage (66Volt) was noticeable and could only be reduced with a perfectly adjusted motor. The same continuous power as the old motor he never had.The old motor, the heat could simply be dissipated by the forced ventilation!!!

[SBK74]

For all the hype, DC fast charging doesn't seem nearly as widespread around me, so I'm fine with 6kW+ level 2. Charging any faster than that without thermal management is a recipe for battery destruction.

When commuting I never use and need DC fast charging indeed, but DC fast charging allows me to do trips around the Netherlands, drive to Germany and do tours with ICE bikes. I can always leave home or work unexpectedly on low SOC and DC charge on the way. I realize I'm living around many DC chargers , but I do not consider DC charging a hype at all. The battery case on the SR/F looks like thermal management has been given more attention.

[grmarks]

As for the motor fins.  There was an old live feed from the Zero execs saying the current fin design was used because it was a cheaper manufacturing process but were a little embarrassed when people pointed out how bad the air flow was with that design.

This one should get air moving all around the motor getting more air to more surface area of metal cooling it better.

When Zero had the pod cast on the IPM motor the motor engineer said that the air flow was turbulent around the motor, so it didn't make hardly any difference the fins going across rather than around. The motor is behind the battery on both the SR/F and the SR so I would expect the same kind of air flow.

[grmarks]

As Zeros' chief electrical engineer who designed the IPM motor said, if a motor produces a certain amount of power then it makes no difference if the voltage is 100V or 400V it produces the same amount of heat in the motor.

That's the greatness bullshit I've ever heard!
What makes the coils of an electric motor get hot? From voltage or the current 

With such a statement, the probability of CCS equals "Zero" 

This is a quote from Zero's motor designer, He knows a lot more than me, and probably you.

My guess is with a higher voltage motor you use smaller wires in the windings because they carry less current but more windings give more power, but the smaller wires get hot with less current, the end result is the same heat.