Fuel Savings from Roadbed Electrification Pays for the Power Plant In 14 Months

wrote:


A *sensible* response would involve you explaining how parts that are "detached from the chassis" have any function at all.

Now I remember---you are the guy who put the screws into the cover of the equipment and polished up the case. We thank you for your service.
People who know stuff like physics tend to talk about problems in concrete terms---they would be interested in showing me why my idea doesn't work, and they wouldn't be afraid to describe things in detail. You are obviously bluffing.
-tg

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Unsprung weight in an automobile (motorcycle, bicycle, etc.) typically is in the wheels before the suspension and is a concern largely for high performance and ordinary performance on imperfect roads. There are vehicles with the motor(s) in the hubs of the wheels. Conventional affordable electric engines tend to be quite heavy (emphasis on economical because if you wish to spend enough, this weight can be dramatically reduced.)
The proposal for electrified roads suggests that these roads could be made quite smooth and turns radiused and possibly banked to reduce the need for less unsprung weight. It's all a trade-off.
I am particularly interested in carbon-fiber wheels but they are not DOT approved for road use and regardless, changing the tires is very difficult to do without damaging the rims.
Oh, check this out: http://www.pmlflightlink.com/news.html
The article in that link is problematic in one regard, "Torque Ripple" is actually beneficial to traction as evinced in such applications as "big bang" engines which are either engines with, for example, two cylinders firing in 45 degree or less (Suziki, Harley-Davidson, Honda's V4 modified to two oval cylinders and four connecting rods) and an exotic 16 cylinder engine that fires four cylinders at once.
The same 'ripple' or pulsed power effect is what makes anti-lock brakes more effective than conventional.
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Thanks. These are the people involved in this:
http://www.hipadrive.com/Documents/new%20york%20times%20sema%20article.pdf
I should point out, however, that in-the-hub isn't a *requirement* to benefit from wheelmotors. Nice, but not necessary.
-tg

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On 6/4/09 3:09 PM, in article snipped-for-privacy@f16g2000vbf.googlegroups.com,

Can you point me to a wheelmotor that is not in the hub?
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You know, I am posting from a philosophy group, and this kind of definition thing is always lots of trouble. The people in the reference make flat motors, and so it is in their interest to think in- the-hub. If you mount four electric motors to the chassis, and have some kind of universal-joint stub connected to the wheel, what do you call that other than a wheelmotor?
What I'm pushing in these posts is the idea of multiple companies making motors with whatever innovative de-coupling of the mass of the electric motor from the 'sprung' mass of the 'wheel' they can come up with. The chassis has some mounting points, but the rest of it is subject to the creativity or stupidity of the motor people.
Yeah, I know, I'm a crazy free-market optimist. If you have the chops to put together those cars, why don't you try it yourself?
-tg
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snipped-for-privacy@earthlink.net wrote:

No. That's just another inboard motor arrangement. You see, in the case you described the motors would be above the suspension.

It is very simple. Think of motors in a wheel bouncing down the road. Heavy is not good because too much energy is fed right back to them because the suspension cannot transfer it quickly enough to some putative absorber in the chassis.
However, if one distributes the total desired power among four wheels, then each will be lighter and life is good again.
My friend, I have been building race setups for forty years. I know this shit.
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Glad to hear it. I like to talk to people who know what they are talking about. However, my point does not change---the benefit of 4 electric motors is pretty much the same even if they are 'mounted inboard'. I am not interested in worrying about what you call them.
You also posted something about 8,000 hours for an electric motor lifetime. Where do you get that figure? And what is the failure mode?
-tg
-tg
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snipped-for-privacy@earthlink.net wrote:

Never seen "inboard" mounted wheels on an autombile. What would they look like?
Regardless, more motors means more likelihood of failure of one and compounded loss of reliability/efficiency for all of them. It's a trade off: with four in-hub motors you can have four weaker, lighter wheel motors rather than one big motor in the chassis.
> You also posted something about 8,000 hours for an electric motor > lifetime. Where do you get that figure? And what is the failure mode?
That was probably wrong. I built a couple in-hub brushed electric bicycles (front hub) and 8,000 hours was the figure for them. (The brushes lasted longer than the motors. Real crap that those motors were.) It depends upon the motor and operation, of course. I can't even guess what an arbitrarily chosen in-hub motor for an automobile would get and I'm about to leave for the day job so I don't have time to research it.
Regarding mode, a catastrophic failure (sudden, all at once) can occur in a brushed engine, or through bearing failures of any. We don't have air bearings for large engines yet. However, electric engine performance usually (depending upon type) diminishes long before failure so you have to look to the reliability as performance figures rather than MTBF.
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http://teslamotorsclub.com/technical/303-hub-motors-dual-motors.html
Scroll down to number 8 I think. I would dispense with disc brakes on the wheel and put some very simple parking-brake device on the inboard side as a 'final ultimate' emergency stopping option, relying on electric braking.

I think reliability has to be thought of differently from the simple formula. You could argue that a car with 4 tires is more likely to have a flat than a motorcycle with two, but that doesn't make me feel that motorcycles are safer than cars.
The idea, which I've repeated many times now, is that the market will yield better motors if there are 40 million sold in the US every year rather than 10 million. And a motor that weighs 75 lbs is easy to swap out; I think electric motors can be rebuilt a couple of times at least---and much easier than rebuilding an ICE or a transmission.

I'm pretty sure lifetimes are rated much higher for brushless electric motors. But just think--- if you average 40mph, 8,000 hours would get you 320,000 miles. And if you have to replace brushes, so what?
As I said before, I don't know what the best type of electric motor will end up being used---maybe different for different applications.
-tg

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On 6/5/09 7:52 AM, in article snipped-for-privacy@d31g2000vbm.googlegroups.com,

That is not an inboard hub motor. It is not a hub motor at all. It is a perfectly conventional motor. A hub motor is inside the wheel, not just something that drives the hub. There are no motors or engines that drive the wheel anywhere but to the hub. None drive at the rim of the wheel (except for a couple exotic show motorcycles that are impractical. Citations available.)
If I were home I'd shoot some pics of the Porsche's IRS and you would see it's connected to the transmission just like that illustration done by the would-be impressionistic, unlearned contributor to the site in question.
So, let's stick to real-world terms. I would not use the post in question as a source of any authority.

Old hat. We have been mounting disc brakes on drive shafts for many years. I think Lotus does it. I have done it. You can't turn a disc brake into a generator. Its lack of a flywheel effect and radius make it impractical, and also consider that all electric motors are also generators, but not particularly powerful.

Yup, rather like the original Jeep - lots of 'em, bolt access outside of the obstructions, all that.

I don't know if brushless motors would work with a purely electric (non-hybrid) car. They have to be nudged into motion before the fields engage. Brushes are necessary to move off a dead stop (or the hybrid motor has to nudge it.)
Remember, too, these are probably three-phase motors. Three phase motor fields must be kept synchronized in each motor or they become quite inefficient.
FWIW, I know a fellow in France who has a Tesla. He's a bit unhappy about the recall. I'm looking forward to his driving impression.
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You lost me there---I'm in favor of using perfectly conventional motors if that works.

The picture is just so people can visualize the possible configuration. I don't see anything wrong with it.

Again you've lost me---you are obviously misinterpreting what I said. Braking is done by the electric motor; for most of the braking period you are recovering the kinetic energy, which is why it is called regenerative braking. The ultimate implementation would have no disc brakes at all. If you need further explanation please let me know.
-tg

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On Fri, 05 Jun 2009 09:48:31 -0700, tgdenning wrote:

Motor/generators are transducers, not brakes. That means you can only slow down, not come to a complete stop. If the electronic controller failed, you couldn't even slow down. How big a market do you expect for cars without brakes?
Remember, everything looks easy to the guy who doesn't actually have to do it.
snip>
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wrote:

Don't know much about stepper motors, do you? http://en.wikipedia.org/wiki/Stepper_motor
However, any vehicle would have brakes for parking if nothing else.
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On Fri, 05 Jun 2009 19:35:02 +0100, Androcles wrote:

Well, I've designed control systems and drivers for them, but I haven't ever seen one used for vehicle propulsion or regeneration. Please tell us more about that. An example or app note would be nice. I could think of several uses for a nice four quadrant stepper system.

The question was about the size of the market. I'd want disk brakes, or equivalent, capable of several reliable maximum emergency stops, and I don't think I'm alone in that. Call me old fashioned...
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wrote:

Just because you've never seen it doesn't make it a negative requirement, the wheel is redesigned for every new model of car. ICEs are redesigned and improved constantly, why not electric motors?
What's wrong with a bicycle wheel with alternate permanent magnets around the rim and a horseshoe stator with a single coil to drive them, fitted like a caliper brake?
http://homepages.nyu.edu/~jh15/bikes/images/stdreach.jpg
Speed control is merely frequency control, you can get the magnets by recycling old hard drives, the magnets in those are very strong. Embed the magnets in a solid tyre or fit them to the spokes. Cheap and super simple, easy to fit, no problem with torque.

Such as regenerative braking, perhaps? Oh wait, you are against that idea, right?

Nothing wrong with belt and suspenders or wearing a parachute if you plan on strapping a military jet to your arse and jumping up the air.
But the real solution is rail; the infrastructure is mostly in place, its cheaper than road beds, easily electrified and vehicles can be individually controlled and navigated by computer, eliminating the train. You load your vegetables on a truck and send it direct to destination, at night, phasing out 18 wheelers. Who needs truck drivers anyway? Re-employ them as maintenance crews.
If you want to go somewhere you call a rail taxi, board it and the computer takes you to your destination. Or you buy your own computerized rail vehicle. Leave the freeways for those that want to kill themselves with ICEs. Size of market? The whole damn world. Can it be done? Cities had trams, computers are cheap, cell phones... of course it can. Breakdown? push the vehicle off the main rails into a siding and send a repair crew with a tow truck.
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On Fri, 05 Jun 2009 22:30:02 +0100, Androcles wrote:

motors.html
How is that different from a multipole PM motor? Once you learn some physics, you may be able to put your imagination to practical use. Until then, it appears it will mostly provide entertainment.

Not at all. I'm just waiting for you to explain how to do it with a stepper motor. I don't think it's in the wiki, so you may have to actually think realistically about the problem.

Or driving at 80 on the freeway. You do know, don't you, that nearly all vehicle hydraulic brake systems are actually two redundant systems? Most people consider brake reliability important.

It sounds easy, until you start to understand some of what's involved. But dream on, you'll never be the one actually expected to do it.

Using the rails? Or do you plan to still have roads for when you really need something to work?
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wrote:

Bwhahahahahaha! Pissed off because you've never been practical, huh?

You do know, don't you, that nearly all aircraft hydraulic systems are actually never used for brakes?
Should you ever learn engineering you may never be able to put your pathetic lack of imagination to practical use. It appears it will mostly provide mild amusement.

Rail was always easier than road, that's why it was built first. It's easier today, we are not limited to grossly underpowered steam locomotives that can't climb hills so we wouldn't need the tunnels and bridges the Victorians built. Why, I've even heard of ships that are nuclear powered, unlike the coal-fired Titanic of your non-existent old-fashioned imagination.
But you carry on living in the 20th century with your electric motors that are also generators, but not particularly powerful like this:
http://www.railwayclassics.com/images/acl01/ACL501%20color.jpg

No, and I also plan to dump you for the miserable and highly limited unimaginative old-fashioned fuckhead you really are.
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wrote:

I think maybe you are not reading carefully and just overreacting. I said that electric motors can be reversed, which means that they have as much 'stopping potential' as they have starting potential.
===========================================Yep, if you can spin the wheels at start up then you can apply the same torque stopping them. However, braking does a better job in an emergency because most brakes can lock the wheels even when the motive power is insufficient to spin the wheels at startup.

No, I'm not wrong. Regenerative braking is a real effect, and with a smart controller you will avoid losing traction.
I'm not saying it is a trivial matter to set up such a system but there's nothing that prohibits it. ===========================================It's as simple as it can be, actually. The back-emf that the motor generates limits the current and if you drive the motor faster through the shaft the current reverses, which is exactly what you want to recharge a battery. You do not need to reverse the direction of the motor. For a vehicle the energy losses are overcoming air resistance and bearing/gearbox friction. Any braking is an additional loss as heat which cannot be recovered.

There are cables and there are cables. And we are not exerting tons of force in this application.
-tg ==============================================You seem to be trying to educate a complete idiot. Good luck!

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wrote:

Huh? If you short any motor, AC or DC, it will stop faster than you can finish the word "stop".

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That what I said when he said circular furrows were impossible.

John Fields has an IQ of 14.
His case worker keeps him posting here to keep him off the street.
Bret Cahill
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