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podolefsky
26 March 2013, 1910
Richard's thread on the Hyosung scooter (http://www.elmoto.net/showthread.php?2878-Hyosung-ST-E3-EVA) reminded me about ZEV (http://www.zelectricvehicle.com/). They've been taking Chinese scooters and making pretty nice electric versions for a few years. I just saw they have a new model, the 10 LRC, with a 75mph top speed and claimed 140 mi range (at 55 mph). Price is $13,900.

Someone over there likes Hayabusas...

http://zelectricvehicle.com/22.html

It's a 10 kWh pack, so I'm skeptical of the 140 mi range claim. The aerodynamics might buy them something, but I doubt it's that much. Still, if you're into getting groceries, this looks pretty sweet. I have to admit, for just running errands around town, I do like my scooter quite a bit.

Skeezmour
26 March 2013, 2115
I hate when they play games with the torque. " -The ZEV has 2.5 X the torque of the ZERO. " Well I hope so since your direct drive. Forget that the Zero has gear reduction.

Does anyone proof the website? This did make me chuckle. "10 Kw (10,000 WATTS) OF CONTINUOUS OUTPUT POWER. Motor rated to 15,000 Kw" I could make a sweet ship drive out of that thing :)

Sorry off my soap box.

Skeezmour
26 March 2013, 2129
WOW if you don't want to be pissed off at total BS do not read the FAQ on that website.

MAN they BASH hard on both Zero and Brammo. Good plan....NOT!

podolefsky
26 March 2013, 2218
Yeah - agreed, it's too bad they had to go so negative, and generally just make a lot of nonsense statements (in fairness, I think that's called "marketing"...they just did a really bad job at it). The bit about the "illogical" battery arrangement and tiny rear brake on the Empulse is pretty hilarious...

They do make a pretty nice hub motor scooter. The lower models are basically the same Chinese made chassis as my R-Martin, but with a much nicer motor/controller, better battery, nicer build all around.

jazclrint
26 March 2013, 2333
Chinese right? If that's the case, it's not surprising.

teddillard
27 March 2013, 0152
Not Chinese. Darus H Zehrbach III. Long record of interesting accomplishments (https://www.google.com/search?q=Darus+Zehrbach+electric+motor+fraud&aq=f&oq=Darus+Zehrbach+electric+motor+fraud&aqs=chrome.0.57.13093j0&sourceid=chrome&ie=UTF-8#q=Darus+Zehrbach+convictions&hl=en&ei=PbVSUY-WLsmx0AHTg4DIDg&start=10&sa=N&bav=on.2,or.r_qf.&fp=116d73714d247927&biw=1304&bih=765).

I had a long series of exchanges with him and lost interest when his claims started looking a little like a pattern... (One of his three convictions (http://www.ca4.uscourts.gov/opinions/Unpublished/024863.U.pdf) that I found was for a motor that he apparently bilked a bunch of investors for.)

As it turned out, nothing he told me he was "about to release" (18" 30kW oil-cooled motorcycle hub motor) ever materialized.
http://evmc2.wordpress.com/2010/08/10/hammarhead-volta-and-bigass-zev-hub-motors/

(PS: Funny how everything that's bull**** gets called "Marketing". I call it "bull****".)

ZoomSmith
27 March 2013, 0817
Unfortunately, a jerk with zero emissions is still a jerk.

frodus
27 March 2013, 0914
the faqs are funny.

The Brammo had a 50/50 weight distribution and dual piston rear caliper.... and its not tiny.... But it is smaller than the front...just like every motorcycle I've seen. You want more braking in the front!

Water cooled controller is going to beat air cooled every time.

And Brammo dynos every bike as far as I know.

There's so much wrong there.... I'm surprised he can fit 10kwh of GBS in those scooters.

podolefsky
27 March 2013, 0958
I had a lot more respect for the company before I read the FAQ. They're based in the US (Pittsburgh I think). Basically they take the Chinese chassis and outfit it with nicer components. I *think* they make their own motors.

Someone I know here has one, and they are a good product. A lot nicer than my scooter with the same chassis.

They should really just focus on marketing their product for what it is - a nice electric scooter with good range and speed. But they're stuck in the US, so they have to try and convince people that if they buy a scooter they still get to keep their balls. It's no excuse for the b.s. on their site, but I do kind of get where it's coming from.

dhzehrbach
28 March 2013, 1800
Darus H Zehrbach III is a 21 year old student at WVU. Guess he must have started when he was a baby?


I had a long series of exchanges with him and lost interest when his claims started looking a little like a pattern... (One of his three convictions (http://www.ca4.uscourts.gov/opinions/Unpublished/024863.U.pdf) that I found was for a motor that he apparently bilked a bunch of investors for.)

As it turned out, nothing he told me he was "about to release" (18" 30kW oil-cooled motorcycle hub motor) ever materialized.
http://evmc2.wordpress.com/2010/08/10/hammarhead-volta-and-bigass-zev-hub-motors/

(PS: Funny how everything that's bull**** gets called "Marketing". I call it "bull****".)[/QUOTE]

frodus
28 March 2013, 1818
Darus H Zehrbach III is a 21 year old student at WVU. Guess he must have started when he was a baby?

Stay in school kiddo....

dhzehrbach
28 March 2013, 1825
I hate when they play games with the torque. " -The ZEV has 2.5 X the torque of the ZERO. " Well I hope so since your direct drive. Forget that the Zero has gear reduction.

Does anyone proof the website? This did make me chuckle. "10 Kw (10,000 WATTS) OF CONTINUOUS OUTPUT POWER. Motor rated to 15,000 Kw" I could make a sweet ship drive out of that thing :)

Sorry off my soap box.

If you want to play games about torque, then do not raise the issue of the gear reduction. The statement is and remains that the "motor" has more torque than the Zero does. Pure and simple. It beats the Zero motor hands down anytime any day in torque. Now - what you want to argue is not the torque of the motor, but the torque to the contact patch on the ground. But you are still wrong. The problem for your argument is that while the gear reduction does raise the total torque of the much higher reving Zero motor, that torque multiplication is at the rear sprocket diameter. Not at the ground. If the sprocket is 1/2 the OD of the tire OD, the torque you just multiplied is cut in half at the ground.

The torque of an electric motor increases with the cube of the OD increases. When you run an in frame motor, that puts you at a disadvantage vs a hub motor. The hub motor also lets you fill the chassis with battery where the in chassis motor would fit. Lots more space for battery to work with. That is how ZEV stuffs 10 kwh in the LRC 10 and in one of the T series bikes.

With a hub motor you do not have the geometry problems of an in chassis motor drive so you can lower the battery pack and chassis relative to the axle, the pivot point for braking. With the battery mass lowered down in the chassis much lower than Zero or Brammo do or can, the bike squats on hard braking. The rear does not want to lift.

Seems funny on this site all of the crabby talk about what companies are doing that you think is negative expressed by this group in the most negative style. Interesting behavior.

podolefsky
28 March 2013, 1903
Hey dhzehrbach. Glad to have you aboard to explain your product.

You might notice that I've said several times how much I like your products. In fact, everyone here LOVES companies that actually build and deliver products, which yours does (see the other recent thread on vaporware for context).

The only negativity that I can see is:

- some fun with typos --- 15,000 kW...just fix it on your site, problem solved

- some gripes about slight distortions of torque claims --- we can argue about resulting force at the wheel...the fact remains, you're don't say anything about that in your FAQ, you just talk about how much your large diameter motor beats Brammo and Zero on torque, which is technically true but not the whole story

- some misunderstandings of motorcycle geometry and handling --- having weight higher up is just one of many ways motorcycles are different than scooters, it doesn't make them handle better or worse, just different. And the rear brake on the Brammo isn't small for a motorcycle, so that's just a misunderstanding on your part

We all understand how proud you are of your product, and how there is a fine line between marketing and b.s. (Brand X gets your teeth 200% whiter than Brand Y...yeah, right). Just understand that as EV "connoisseurs", we have a pretty low tolerance for anything from the slight distortion to outright b.s. Yes, we are a little crabby...just think of it as tough love.

Again, welcome to elmoto. Glad to have you here.

dhzehrbach
28 March 2013, 2024
Thanks, and big typo clearly. 15,000 watts, not Kw. Have to look for that one and fix.

I will argue that Lower CG does make a huge difference. It is a huge factor in braking. You could not pull a stoppy on a ZEV if you tried even with the much larger contact patch of the tires. The mass under the axle makes the bike squat, not raise. So where most cycles have to run small rear brakes realive to the rear, we do not. That was the big goal of the design. We beat everyone hands down in the certification braking tests as the bike gets near equal grip on both tires with equal sized brakes.

Lower CG lets you flick the bike from side to side in turns. A higher battery mass makes that transiant flick slower. My Kaw requires you have to muscle the bars to flip it in the esses.

Lower CG has a side benefit. When you drop it, you are not picking up as much weight. I can pick up a 7100 with one hand from when its laying down.

We will get around to doing the motorcycle motor Ted Dillard went off the deep end ranting false accuaations about our delaying. But the market worldwide told us that we were better off putting money into the new double stator motor on the little 2700 so we could launch that bike, and into the big motor on the 10 LRC so we could finish launching that bike and the T-10 that uses the same motor. No offense to cycle lovers, it just was better business sense to complete those projects.

I understand tough love. No problem. Just don't invent stuff. Sorry if people do not like comparative areas on our web site. We compare price, performance, warranty, anything we can. This is the first time I ever heard anything negative about doing that. We get constant emails from people about their appreciation of the comparisons of various factors of different companies bikes.

For the record, my son, the Darus Zehrbach the III Ted wrote of is only 21., My other son D Zehrbach is only a few months old. The document that Ted referred everyone too did not mention any Darus H Zehrbach III or any number nor anyone with an H. It also did not mention investors as Ted said, nor motors at all, just engines. Guess Ted does not know the difference between an engine and a motor? Nothing referred to ZEV or bikes or any EV either.

Glad you like the bikes. We have a motorbike coming out in about 2 months as the next offering.

Darus H Zehrbach II





Hey dhzehrbach. Glad to have you aboard to explain your product.

You might notice that I've said several times how much I like your products. In fact, everyone here LOVES companies that actually build and deliver products, which yours does (see the other recent thread on vaporware for context).

The only negativity that I can see is:

- some fun with typos --- 15,000 kW...just fix it on your site, problem solved

- some gripes about slight distortions of torque claims --- we can argue about resulting force at the wheel...the fact remains, you're don't say anything about that in your FAQ, you just talk about how much your large diameter motor beats Brammo and Zero on torque, which is technically true but not the whole story

- some misunderstandings of motorcycle geometry and handling --- having weight higher up is just one of many ways motorcycles are different than scooters, it doesn't make them handle better or worse, just different. And the rear brake on the Brammo isn't small for a motorcycle, so that's just a misunderstanding on your part

We all understand how proud you are of your product, and how there is a fine line between marketing and b.s. (Brand X gets your teeth 200% whiter than Brand Y...yeah, right). Just understand that as EV "connoisseurs", we have a pretty low tolerance for anything from the slight distortion to outright b.s. Yes, we are a little crabby...just think of it as tough love.

Again, welcome to elmoto. Glad to have you here.

podolefsky
28 March 2013, 2033
Hey Darus - looks like we're finding some common ground. Just ignore Ted...he needs his Geritol ;) (see other thread (http://www.elmoto.net/showthread.php?2868-ABS-anyone&p=36515&viewfull=1#post36515)).

I see what you're saying about braking. It makes sense now, but you might want to tone down the negative rhetoric about the Empulse (anyone who knows motorcycles will be scratching their head, which is exactly what happened here).

On handling, I have scooters, an electric motorcycle, a gas motorcycle...they all ride differently. It's true that lower CG scooters give them unique handling...whether or not it's "better" is totally subjective. Most reviewers of the Empulse say it is one of the best handling *motorcycles* they've every ridden, which is saying a lot. People get really emotionally invested in their bikes, as you probably know, so you shouldn't be surprised when people gripe, or even get downright pissed, when you say a scooter handles better than a motorcycle. Just saying.



If you want to play games about torque, then do not raise the issue of the gear reduction. The statement is and remains that the "motor" has more torque than the Zero does. Pure and simple. It beats the Zero motor hands down anytime any day in torque. Now - what you want to argue is not the torque of the motor, but the torque to the contact patch on the ground. But you are still wrong. The problem for your argument is that while the gear reduction does raise the total torque of the much higher reving Zero motor, that torque multiplication is at the rear sprocket diameter. Not at the ground. If the sprocket is 1/2 the OD of the tire OD, the torque you just multiplied is cut in half at the ground.

I think there's some funny physics going on here. Please don't take this as an attack - just some well-meaning clarification.

Talking about "the torque to the contact patch on the ground" is sort of meaningless. Torque is just torque - it doesn't matter what the wheel diameter is. What you want is the *force* at the contact patch.

Force = torque / radius. So, let's assume ZEV has 185 Nm and Empulse has 63 Nm (according to your site). If the ZEV has a typical scooter tire, the radius is about 10", or 0.24m, so the force at the contact patch is about 770 N. The Empulse has lots of gear ratios with it's transmission, but let's take a typical one for an elmoto which is 5:1. That means torque at the wheel is 315 Nm. If the rear wheel radius is 13" (0.33 m), then force at the patch is 954 N. So actually, the Brammo beats the ZEV in terms of force at the contact patch (which is the number you're after).

Now, don't get me wrong - 770 N at the patch is really impressive for a scooter. Especially considering 1) it is instant (unlike most scooters that have a serious lag due to the centrifugal clutch), and 2) it is from zero RPM.

15 kW peak is also great, about 20 HP, which puts your scooter on par with a 150cc, a lot better than others that are closer to a 49cc (like mine).

You should play that up. Explain how all this means your scooter will feel really fast compared to a gasser, it's quieter and less stinky. It costs pennies per mile to drive and never needs an oil change. That will probably get you further than misleading arguments about torque, or any other negative stuff aimed at other EV companies that everyone likes.

Cheers.

Hugues
28 March 2013, 2252
... that torque multiplication is at the rear sprocket diameter. Not at the ground. If the sprocket is 1/2 the OD of the tire OD, the torque you just multiplied is cut in half at the ground.

The torque of an electric motor increases with the cube of the OD increases. ..

This Is the first time I hear such a theory ! Who told you things work this way ? You should get back to them and slam their fingers hard with a thick wooden ruler ! LOL

Thanks Noah for the physics 101 lesson !

teddillard
29 March 2013, 0321
"On Aug 11, 2010, at 5:30 PM, dz3@zelectricvehicle.com wrote:

Here is the answers to the questions you had, we don't have the physical specs on the

classic model yet but we will send those to you as soon as we can.

Darus H Zehrbach III

Certification Engineer"

...whatever.

"...went off the deep end ranting false accuaations"? Oh please. There is nothing there or here beyond simply quoting your email to me and saying it was lame. Take a pill. You clearly have never read one of my rants.

Anyone who wants to read the public record and decide for themselves can do so, that's why I posted the Google link. I'm not here to destroy anyone's reputation. Not even the Chinese. (anyway... for the love of ****. I posted this story (http://evmc2.wordpress.com/2010/08/08/zev-says-to-brammo-zero-think-different/) comparing the Enertia with his scooter as well as other pro-ZEV posts. Apparently that's not enough for an unpaid blog post - though it was well enough for Enertrac to accuse me of being on ZEV's dole.)

I've already wasted far too much of my time reading this man's ridiculous claims, and am sitting this one out. Trash me all you like, anyone who cares can read what I've written and decide for themselves.

EVcycle
29 March 2013, 0519
I think I will step in on the Lower CG comments.

These are non Engineering degree statements. My experience comes from the roads and racing 20+ years in all sorts of 2 and 4 wheel vehicles, drag and road racing.


Lower CG for cars is normally a great way to help in handling. Not so much for Motorcycles. It is surprising how
high the CG is on motorcycles that for many folks just does not make sense. For a scooter and that upright riding position, low cg is great.
The lower CG will not help you in high speed turns, but that was not what the ride is designed for..... :)

On the braking;
I would put up to the test an equal weight motorcycle to your braking results, unless you were just comparing it just to other scooters, but,,,,you did add your Kaw in the same paragraph.
Our 79 cafe racer at 380Lbs will stop quicker than most of the super bikes (Don't ask me why I know this, :) ) and I have never had a "stoppy" issue... ever.
I lay odds your Kaw weights much more than your Scooter.

Richard230
29 March 2013, 0800
Most modern motorcycle chassis engineers seem to believe that concentrating the bike's mass as close to its CG, with the rider on board, results in the best handling and side-to-side transitions.

I love hub motors for their ability to allow more space for batteries in the chassis, but they do nothing for the handling of a motorcycle, as they hugely increase unsprung weight at the rear wheel, which has a very detrimental effect on the rear wheel's ability to follow bumps in the road and also places a lot of weight relative far from the CG, which also impacts high-speed handling.

Attached is a photo of one of the early motorcycles that had a hub motor. It was not a commercial success.

scoot440
29 March 2013, 0924
My two most-ridden bikes these days are a Zero XU and an old Vespa with a rear hubmotor and a hydraulic disc brake and a stock drum brake up front. The Zero truly corners better than any motorcycle I've ever ridden, but the stability in braking on the Vespa is pretty amazing. The higher center of gravity combined with the very low weight actually makes braking a bit hairy on the XU. I have learned to shift my weight to the back and to be very light with the front brake whenever I need to stop quickly. My first-ever accidental stoppie was an eye-opening experience!

So, I'd rather stop on a hub-motored scooter and ride the twisties on the motorcycle.

podolefsky
29 March 2013, 1016
Lower CG for cars is normally a great way to help in handling. Not so much for Motorcycles. It is surprising how
high the CG is on motorcycles that for many folks just does not make sense. For a scooter and that upright riding position, low cg is great.
The lower CG will not help you in high speed turns, but that was not what the ride is designed for..... :)


Exactly...a scooter isn't designed to ride like a motorcycle. The only point in comparing them is to point out the pros and cons of each - neither is inherently better.

Upsprung weight definitely matters for performance, but remember we're talking about scooters here. They're not racing on a track or even up a canyon, they're just skipping around town. A hub motor makes a lot of sense since it gives you more space in the frame for batteries and storage, it means no chain or belt drive. It's a simple, elegant design that solves a number of problems. The only problem it really causes is unsprung weight, which is pretty much a non-issue on a scooter.

My electric scooter (which is very similar to a ZEV, but lower power) is WAY easier to ride for a beginner than my motorcycle, and in a lot of ways nicer for riding around town even for an experienced rider. It seems like folks that are critical of the hub motor and lower CG in a scooter are expecting them to be something they're not.

I'm not saying everyone should go buy a scooter - a huge reason I built my motorcycle is because my scooter was ONLY good for skipping around town. Just saying it's apples and oranges.

EVcycle
29 March 2013, 1031
Exactly...a scooter isn't designed to ride like a motorcycle. The only point in comparing them is to point out the pros and cons of each - neither is inherently better.

Upsprung weight definitely matters for performance, but remember we're talking about scooters here. They're not racing on a track or even up a canyon, they're just skipping around town. A hub motor makes a lot of sense since it gives you more space in the frame for batteries and storage, it means no chain or belt drive. It's a simple, elegant design that solves a number of problems. The only problem it really causes is unsprung weight, which is pretty much a non-issue on a scooter.

My electric scooter (which is very similar to a ZEV, but lower power) is WAY easier to ride for a beginner than my motorcycle, and in a lot of ways nicer for riding around town even for an experienced rider. It seems like folks that are critical of the hub motor and lower CG in a scooter are expecting them to be something they're not.

I'm not saying everyone should go buy a scooter - a huge reason I built my motorcycle is because my scooter was ONLY good for skipping around town. Just saying it's apples and oranges.

Agreed!

(which one is the apple?) :)

podolefsky
29 March 2013, 1347
This Is the first time I hear such a theory ! Who told you things work this way ? You should get back to them and slam their fingers hard with a thick wooden ruler ! LOL

Thanks Noah for the physics 101 lesson !

No problem...that's my job ;)

Here's a motor 101 lesson: I'm not sure where torque proportional to OD^3 comes from. According to Electric Motors and Drives, by Hughes (not to be confused with Hugues), torque is proportional to D^2 * L, where D is diameter and L is length of the motor. In other words, all else equal (windings, current, etc), torque ~ volume. This goes for *any* electric motor.

So, if two motors take up the same volume, there's no advantage to having a narrow, large diameter vs a wide, small diameter. The reason hub motors produce more torque with the same current is mostly because of the lower kV winding, not the geometry.

dhzehrbach
29 March 2013, 1724
See http://www.proteanelectric.com/?page_id=154&cat=23 go to Packaging and Integration document for why raising the diameter of a motor creates more torque than simply making it longer. Other papers on that site might help increase understanding of hub motor dynamics.

For the above reasons, best peak and continuous torque can be achieved for a given field strength by positioning the air-gap against the assumed largely cylindrical outer surface of the machine. This immediately drives the design towards a radial flux, outer-rotor layout as being most likely to meet the peak and continuous requirements with minimum package size and mass.
Consider equation 1: ( ) ( )
For a given machine design, torque scales approximately to the above rule, where DiameterAG is the airgap diameter. In simple terms this is brought about by considering the basic mechanics and geometry of the machine. By doubling the diameter of the machine, you have both doubled the lever arm at which the tangential forces are reacted, and also doubled the airgap shear area, resulting in a doubling of the tangential forces also – hence torque is quadrupled. In doubling only the length of the machine, you are simply doubling the airgap shear area, which doubles the tangential forces and torque only. Note that both continuous torque and peak torque scale closely to this relationship, in the case of continuous torque then the limiting factor is heat flux and not magnetic flux, but the principle is broadly similar.
By assuming a cylindrical machine, see equation 2: ( ) ( )
Where DiameterO is the outer diameter of the machine package. By accepting that DiameterAG ≈ DiameterO for an outer-rotor radial flux machine, dividing (1) by (2) gives the following approximate relationship: ( )
So fundamentally no matter whether the designer plays with the diameter or the length of a cylindrical, outer-rotor, radial flux machine, it will still need to take up approximately the same amount of litres of valuable wheel space in order to produce the required torque1.
However, energising the airgap requires only a certain radial depth to the machine, and once the machine reaches a diameter where the inner diameter of the active components is large enough, the motor can essentially take on a toroidal form and the rules that govern the occupied volume change subtly.
Assuming that the radial depth of the active motor components is kept constant, and the diameter and length of this machine concept are free to be scaled, then the volume of these components follows known rules for a toroid, proportional to that shown in equation (4): ( ) ( )
Where DiameterC is the diameter of the centroid of the toroid section. By accepting DiameterC ≈ DiameterAG it can be shown that in general, for a toroidal motor, dividing (1) by (4) gives:
(5)
So, as the outer diameter of the machine increases, at some point it can transition from a cylindrical to a toroidal machine, and the Nm/litre performance potential begins to rise from an essentially constant value to being approximately linearly proportional to the machine diameter, see Figure 5 and Figure 6.

No problem...that's my job ;)

Here's a motor 101 lesson: I'm not sure where torque proportional to OD^3 comes from. According to Electric Motors and Drives, by Hughes (not to be confused with Hugues), torque is proportional to D^2 * L, where D is diameter and L is length of the motor. In other words, all else equal (windings, current, etc), torque ~ volume. This goes for *any* electric motor.

So, if two motors take up the same volume, there's no advantage to having a narrow, large diameter vs a wide, small diameter. The reason hub motors produce more torque with the same current is mostly because of the lower kV winding, not the geometry.

podolefsky
29 March 2013, 1737
...why raising the diameter of a motor creates more torque than simply making it longer. Other papers on that site might help increase understanding of hub motor dynamics.

That is correct - why you have a D^2 term and linear L term in t ~ D^2*L.


By doubling the diameter of the machine, you have both doubled the lever arm at which the tangential forces are reacted, and also doubled the airgap shear area, resulting in a doubling of the tangential forces also – hence torque is quadrupled.

Yup - in other words, torque is proportional to diameter squared, not cubed. If it were cubed, doubling the diameter would increase torque by a factor of 8.

lugnut
29 March 2013, 1845
So, as the outer diameter of the machine increases, at some point it can transition from a cylindrical to a toroidal machine, and the Nm/litre performance potential begins to rise from an essentially constant value to being approximately linearly proportional to the machine diameter, see Figure 5 and Figure 6.

Actually an unmentioned aspect is that the toroidal shape of these wheel motors is attributable to the increased pole count. This increases the electrical frequency relative to mechanical rotation which is acceptable for the ungeared wheel drive but results in poor power density. The net result is that wheel motors will be at a disadvantage in terms of mass and cost. They seem to have found a niche market in electric bikes and scooters for the time being, but a serious design effort with a high speed motor will eventually win out offering reduced mass and cost with higher performance.

lugnut
29 March 2013, 1858
With the battery mass lowered down in the chassis much lower than Zero or Brammo do or can, the bike squats on hard braking. The rear does not want to lift.

I don't follow the reasoning here. The fact that your scooter squats under braking is due to the rear wheel brake bias, not the height of the battery. Show me squatting with a front brake only.

podolefsky
29 March 2013, 1914
However, energising the airgap requires only a certain radial depth to the machine, and once the machine reaches a diameter where the inner diameter of the active components is large enough, the motor can essentially take on a toroidal form and the rules that govern the occupied volume change subtly.
Assuming that the radial depth of the active motor components is kept constant, and the diameter and length of this machine concept are free to be scaled, then the volume of these components follows known rules for a toroid, proportional to that shown in equation (4): ( ) ( )
Where DiameterC is the diameter of the centroid of the toroid section. By accepting DiameterC ≈ DiameterAG it can be shown that in general, for a toroidal motor, dividing (1) by (4) gives:
(5)
So, as the outer diameter of the machine increases, at some point it can transition from a cylindrical to a toroidal machine, and the Nm/litre performance potential begins to rise from an essentially constant value to being approximately linearly proportional to the machine diameter, see Figure 5 and Figure 6.


Oh! I see...for toroidal the torque density relationship changes, basically because you get a big hole in the middle. That's why the reference cited goes on to say:

"In order to realise the gains, it must be possible to package another component inside the toroid, where this component serves some other useful purpose in the context of the final machine assembly. In the context of an in-wheel motor, this means a toroidal motor having a large enough internal diameter to surround, for example, the vehicle wheel bearing or part of the suspension system – i.e. parts that have clear functions and take up volume for other purposes in the wheel assembly."

If you *don't* put something useful in the empty volume, then you just have wasted space. If all you put in there is an axle, it doesn't buy you much, and you've basically got the same torque density as a cylindrical motor.

podolefsky
29 March 2013, 1940
I don't follow the reasoning here. The fact that your scooter squats under braking is due to the rear wheel brake bias, not the height of the battery. Show me squatting with a front brake only.

Erm...yeah, good point lugnut. Here comes another physics lesson :D

I think the assumption was that if the CM is below the axle, then the bike will tend to rotate downward under braking instead of upward. I think this is wrong for two reasons:

1) The CG still isn't below the front axle, especially with a rider on board.

2) The rotation point during front braking isn't the front axle, it's the front contact patch with the ground. You can never get the CM below that, so the bike will ALWAYS tip upward on front braking.

This isn't just in theory - I have a scooter almost exactly the same as a ZEV - same chassis, lead acid (which means if anything the CM is lower). It acts like any other vehicle when you front brake - it tries to tip upward.

Skeezmour
30 March 2013, 0020
Well seeing as how I have one of them there fancy hub motors on my XR250r conversion I'm very familiar with how they work. Also if you put your Zev on a dyno and compare the power over speed, then compare that to a Zero FX my money is on the Zero SMOKING that thing at all speeds (yes torque to the ground). Don't get me started on what the Brammo would do with torque to the ground given the gearing selections.

But you can either keep fighting with us (true fans of pretty much all things electric) or go fix your typos on your website and focus on your strengths. If you have a great product that is fun to ride and well built you should do fine. Hype that up. Bashing EVERYONE else just makes enemies. If you have one of those bikes out here in the Washington State area I would love a chance to try one out.

dhzehrbach
06 April 2013, 1216
Well seeing as how I have one of them there fancy hub motors on my XR250r conversion I'm very familiar with how they work. Also if you put your Zev on a dyno and compare the power over speed, then compare that to a Zero FX my money is on the Zero SMOKING that thing at all speeds (yes torque to the ground). Don't get me started on what the Brammo would do with torque to the ground given the gearing selections.

But you can either keep fighting with us (true fans of pretty much all things electric) or go fix your typos on your website and focus on your strengths. If you have a great product that is fun to ride and well built you should do fine. Hype that up. Bashing EVERYONE else just makes enemies. If you have one of those bikes out here in the Washington State area I would love a chance to try one out.

Thanks for the heads up on the typos on the web site. I pointed out the typo comments to the web site guys. They think they cleaned up them all. If you spot any additional, please drop us a line at sales@zelectricvehicle.com All such help is very much appreciated. Every company has such instances. I saw a print ad last week for a big food company advertising “sweat potatoes” in a magazine as a case in point.
“Fighting with us”? Where is the fight? You just do not like comparative advertising. Last night I saw a Honda car ad that pointed out the differences in power, etc over the competition, then a truck ad pointing out the differences in range, load, mph, torque, etc over the competition. ZEV does the same. That is not bashing. ZEV takes the advertised power specs and distance and other details right off of the ZERO and Brammo web sites and simply compares them. ZERO states the torque of the ZERO S motor is 68 ft lb. They say, not ZEV, not me. So if ZEV says the hub motor has 2.5 times the torque of that motor when the ZEV motor has 180 lb ft in the standard form and 240 in the Alpine, then that is a fact, not bashing. The statement is fact with strict regard to the motor. You want to argue something different such as after the belt drive torque, no problem. But Zero and Brammo did not list such information so we cannot compare, nor can you. We can all only guess and that is not fair to anyone.
We also do run constant benchmark tests against other company models. Do not forget that some of the ZERO dealers are ZEV dealers also. So we get rather constant feedback on the comparison between the various models and comparison between the brands dealer treatment, warranty policy, cost of replacement parts, etc. I go out to the dealers and test drive bikes back to back and race against the dealer on the competing brand bikes. ZEV vs Zero etc heads up racing. So when we state a comparison, it is fact based off of the representations of ZERO and Brammo on their own websites and in their ads reinforced by the dealer statements and on the street side by side comparison.
We do “focus on our strengths” which are in fact the points you do not like to hear or read. In your words, pointing out any advantage of one design over the other “just makes us enemies”. Sort of Ford vs Chevy at the local BurgerKing? If you do not like the comparison with the LRC vs your cycles, you are going to really hate the new 13.6 kwh battery version with the 60 kw peak, 40 kwh continuous rated, dual stator motor going on the first phase road testing in July. It pulled 106 mph first run before I ran out of road. It was still pulling. We are trying to get clearance to run at the longer Clarksburg, WV airport runway to find out just what it can do. We also have some balancing to do between acceleration/top end/and range as far as the amps settings for the controller. After that - take it over to the Hot Rod mile in Ohio this summer to get an official top speed ticket. Still a “scooter” though, you will not like it.
You guys all love your cycles. That is great. The more you promote, the bigger the entire market, the better it is for us and all other companies in it. Matter of fact, one of the lurkers on this web site just ordered a ZEV 5000 L as a result of this thread discussion.
You clearly do not like scooters vs cycles. No problem. We will get around to making cycles too. There are two prototypes setting in the proto shop and a chassis for a naked bike hanging behind the garage. But in the short run you remind me of the guys that work at the oil field shop near ZEV who go out and ride their Harleys and Gold Wings in groups. This past weekend they had a tag along rider with a Yamaha T Max and his buddy with a Burgman 650. Scooter or not, 650 cc gives those scooters some serious grunt. The big cycle guys tried to run off from them lots of times but as they said “Even at 100 mph them damn scooters were running right with us”. Relax, this is not a them or us class war.
You say “my money” ----etc. This summer is the national electric drag race championships. See http://www.nedra.com/class_rules.html for the rules for your bike. Saying “my money” implies a willingness to place a street racing or sanctioned racing bet. Want to go head to head for enough money to cover shipping a bike across the country and air fare to follow? I once shipped a bike (gas one) to the UK to race and took home a few thou net after expenses. Quite willing to do such a thing again if the money pot is big enough. Otherwise, come to the races, or go to your local track and post your time slip and speed on this site and send me a copy. There is a Nedra race set for Washington in your area in August. http://www.nedra.com/upcoming_events.html
I got on this site and thread after being alerted by some of our customers that someone was attacking one of my children claiming them to be criminals and or me personally. You wonder why other companies’ engineers or company people stay off of these sites? 2nd, I am not the, nor an owner of ZEV, just the engineer that is most visible to the USA. The Z in ZEV is not connected with my name at all.
See you at the races.

teddillard
06 April 2013, 1245
2nd, I am not the, nor an owner of ZEV, just the engineer that is most visible to the USA. The Z in ZEV is not connected with my name at all.

http://nvsos.gov/sosentitysearch/CorpDetails.aspx?lx8nvq=NbdXngviTLPtD3XjLPBy%252fw %253d%253d&nt7=0

Richard230
06 April 2013, 1324
Darus Zehrbach sure must be a busy person. He is a director on the corporate board, the corporate president, the corporate secretary and the corporate treasurer. :confused:

podolefsky
06 April 2013, 1354
Comparative advertising is fine - if you're got more power, more range, things that are fair to compare that's one thing. But comparing torque between hub and geared motors is misleading. Come on, you know that. (If you don't know that, then you aren't much of an engineer.)

Nothing against scooters on this site. Just against b.s.

I think this thread has pretty much run its course.

Skeezmour
06 April 2013, 1712
How do you figure I don't like scooters. I said if you have one out here in Washington State I would love to try one. I just love things on 2 wheels. Even better when they are electric.

teddillard
07 April 2013, 0331
:cool: (http://www.youtube.com/watch?v=5YZuAZ_zLiE)