Fuel Savings from Roadbed Electrification Pays for the Power

[Bret Cahill]

Remember where Rhett manages to steal an old nag toward the end of the
Civil War?

Well, very soon we'll be similarly situated.

When fuel is $15/gallon a sled will be considered a nice ride.

We need to get back to reality:

I don't care if the vehicle has square wheels that don't turn we need
to focus on getting some kind of energy to the vehicle.


Bret Cahill


"My kingdom for a horse."

 

[john joseph]

tgdenning@earthlink.net wrote:

On Jun 5, 3:02 pm, John Stafford <jstaff...@winona.edu> wrote:
On 6/5/09 1:26 PM, in article o6idnVqzaun2_rTXnZ2dnUVZ_gJi4...@giganews.com,

"Bill Ward" <bw...@ix.REMOVETHISnetcom.com> wrote:
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.
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?
True. Thanks for the affirmation, Bill.

But motors can be reversed, and so you can certainly come to a
complete stop using only the motors. However, as I said, there can be
a simple type of brake, since you need something for parking.

No they cannot! Not in real world applications! Try it! Try using only
engine braking. Engine braking has far more stopping potential than an
electric motor. But it still is far from enough!

But the advantage of regenerative braking with four motors is that you
get smooth ABS when it matters----going from fast to very slow. You
*don't* need high-quality disc brakes---you could have a drum operated
by cable.

You are wrong, and now I understand that your automotive engineering
knowledge is just sheer impressionism. Oh, and cables stretch which is
why Volkswagen abandoned cable-actuated brakes in 1953. Catch up.

I certainly understand that many of us would be nervous about driving
the first generation of completely brake-free cars,

Corvettes, and my builds, use fly-by-wire for throttle. No problem.
Catch up.

 

[john joseph]

Bret Cahill wrote:

Remember where Rhett manages to steal an old nag toward the end of the
Civil War?

Well, very soon we'll be similarly situated.

When fuel is $15/gallon a sled will be considered a nice ride.

We need to get back to reality:

I don't care if the vehicle has square wheels that don't turn we need
to focus on getting some kind of energy to the vehicle.

I'd like to know how you manage to feed and breathe - like you got a
job? I ask because we have a lot of intellectually handicapped people
who could probably take your day job - and not pester the rest of us on
usenet with such friggin idiocy.

 

[john joseph]

Bret Cahill wrote:

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.

Motor/generators are transducers, not brakes. That means you can only
slow down, not come to a complete stop. ďż˝

It's a good thing we have alert readers here to debunk regenerative
braking!

Regenerative braking can help if it is geared. Now go read up and come
back later, way later.

How big a market do you expect for
cars without brakes?

Chrysler did pretty well with their Voyager. When the ABS went out,
there was no backup.

Bullshit. ABS works as a normal brake when the solenoid motor fails.

Learn or die.

 

[Bill Ward]

On Fri, 05 Jun 2009 22:30:02 +0100, Androcles wrote:

"Bill Ward" <bward@ix.REMOVETHISnetcom.com> wrote in message
news:y7Odnd0c1pP27rTXnZ2dnUVZ_oudnZ2d@giganews.com...
On Fri, 05 Jun 2009 19:35:02 +0100, Androcles wrote:

"Bill Ward" <bward@ix.REMOVETHISnetcom.com> wrote in message
news6idnVqzaun2_rTXnZ2dnUVZ_gJi4p2d@giganews.com...
On Fri, 05 Jun 2009 09:48:31 -0700, tgdenning wrote:

On Jun 5, 11:26 am, John Stafford <jstaff...@winona.edu> wrote:
On 6/5/09 7:52 AM, in article
a187370d-0d8a-4565-8cb8-407364942...@d31g2000vbm.googlegroups.com,



"tgdenn...@earthlink.net" <tgdenn...@earthlink.net> wrote:
On Jun 5, 8:13 am, john joseph <nowh...@nowhere.nl> wrote:
tgdenn...@earthlink.net wrote:
On Jun 4, 8:58 pm, john joseph <nowh...@nowhere.nl> wrote:

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.

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.

Never seen "inboard" mounted wheels on an autombile. What would
they look like?

http://teslamotorsclub.com/technical/303-hub-motors-dual-
motors.html

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.)

You lost me there---I'm in favor of using perfectly conventional
motors if that works.


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.


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


So, let's stick to real-world terms. I would not use the post in
question as a source of any authority.

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.

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.

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.

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.

Don't know much about stepper motors, do you?

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.

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.

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.

I could think of several uses for a nice four quadrant stepper system.

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

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.

http://en.wikipedia.org/wiki/Stepper_motor

However, any vehicle would have brakes for parking if nothing else.

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...

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.

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.

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.

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.

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.

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

 

[John Fields]

On Fri, 5 Jun 2009 12:41:43 -0700 (PDT), Bret Cahill
<BretCahill@peoplepc.com> wrote:

Remember where Rhett manages to steal an old nag toward the end of the
Civil War?

Well, very soon we'll be similarly situated.

When fuel is $15/gallon a sled will be considered a nice ride.

We need to get back to reality:

---
But Rhett was fantasy.

The reality is that if fuel goes to $15 per gallon there'll be an awful
lot of us working from home.

Haven't you heard of the Internet?
---

I don't care if the vehicle has square wheels that don't turn we need
to focus on getting some kind of energy to the vehicle.

---
Why?

If the wheels are square and won't turn, then putting energy into the
vehicle is just wasting energy, which is what you're saying should be
avoided.

Just another blunder on the uphill road leading to your becoming, at
best, inadequate, I suppose...
---

Bret Cahill


"My kingdom for a horse."

---
Your "kingdom" isn't worth a horse.

JF

 

On Jun 5, 7:28 pm, john joseph <nowh...@nowhere.nl> wrote:

tgdenn...@earthlink.net wrote:
On Jun 5, 3:02 pm, John Stafford <jstaff...@winona.edu> wrote:
On 6/5/09 1:26 PM, in article o6idnVqzaun2_rTXnZ2dnUVZ_gJi4...@giganews.com,

"Bill Ward" <bw...@ix.REMOVETHISnetcom.com> wrote:
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..
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?
True. Thanks for the affirmation, Bill.

But motors can be reversed, and so you can certainly come to a
complete stop using only the motors. However, as I said, there can be
a simple type of brake, since you need something for parking.

No they cannot! Not in real world applications! Try it! Try  using only
engine braking. Engine braking has far more stopping potential than an
electric motor. But it still is far from enough!

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.

But the advantage of regenerative braking with four motors is that you
get smooth ABS when it matters----going from fast to very slow.  You
*don't* need high-quality disc brakes---you could have a drum operated
by cable.

You are wrong, and now I understand that your automotive engineering
knowledge is just sheer impressionism.

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.

Oh, and cables stretch which is
why Volkswagen abandoned cable-actuated brakes in 1953. Catch up.

There are cables and there are cables. And we are not exerting tons of
force in this application.

-tg

I certainly understand that many of us would be nervous about driving
the first generation of completely brake-free cars,

Corvettes, and my builds, use fly-by-wire for throttle. No problem.
Catch up.

 

[john joseph]

tgdenning@earthlink.net wrote:

On Jun 5, 7:28 pm, john joseph <nowh...@nowhere.nl> wrote:
tgdenn...@earthlink.net wrote:
On Jun 5, 3:02 pm, John Stafford <jstaff...@winona.edu> wrote:
On 6/5/09 1:26 PM, in article o6idnVqzaun2_rTXnZ2dnUVZ_gJi4...@giganews.com,
"Bill Ward" <bw...@ix.REMOVETHISnetcom.com> wrote:
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.
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?
True. Thanks for the affirmation, Bill.
But motors can be reversed, and so you can certainly come to a
complete stop using only the motors. However, as I said, there can be
a simple type of brake, since you need something for parking.
No they cannot! Not in real world applications! Try it! Try using only
engine braking. Engine braking has far more stopping potential than an
electric motor. But it still is far from enough!

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.

But they do not.

But the advantage of regenerative braking with four motors is that you
get smooth ABS when it matters----going from fast to very slow. You
*don't* need high-quality disc brakes---you could have a drum operated
by cable.
You are wrong, and now I understand that your automotive engineering
knowledge is just sheer impressionism.

No, I'm not wrong. Regenerative braking is a real effect, and with a
smart controller you will avoid losing traction.

You won't need a controller at all because at full-null input it still
will not have enough drag to cause the wheels to lock up.

I'm not saying it is a trivial matter to set up such a system but
there's nothing that prohibits it.

Oh, and cables stretch which is
why Volkswagen abandoned cable-actuated brakes in 1953. Catch up.

There are cables and there are cables. And we are not exerting tons of
force in this application.

Oh yes you are. Consider the diameter of the cable and the task it has
to perform. Same as the old VW Bugs which were still light.

 

[john joseph]

John Fields wrote:

On Fri, 5 Jun 2009 12:41:43 -0700 (PDT), Bret Cahill
BretCahill@peoplepc.com> wrote:

Remember where Rhett manages to steal an old nag toward the end of the
Civil War?

Well, very soon we'll be similarly situated.

When fuel is $15/gallon a sled will be considered a nice ride.

We need to get back to reality:

---
But Rhett was fantasy.

The reality is that if fuel goes to $15 per gallon there'll be an awful
lot of us working from home.

And people who have to "be there" on the job, for example construction
workers (there will be construction) to plumbers and medics will be
making more money than egg heads.

 

[John Fields]

On Fri, 05 Jun 2009 18:29:42 -0500, john joseph <nowhere@nowhere.nl>
wrote:

Bret Cahill wrote:
Remember where Rhett manages to steal an old nag toward the end of the
Civil War?

Well, very soon we'll be similarly situated.

When fuel is $15/gallon a sled will be considered a nice ride.

We need to get back to reality:

I don't care if the vehicle has square wheels that don't turn we need
to focus on getting some kind of energy to the vehicle.

I'd like to know how you manage to feed and breathe - like you got a
job?

---
Yeah, he does.

He's some kind of a court reporter or legal assistant sissy or something
like that, and has delusions of adequacy which led him to start posting
his shit to sci.electronics.design, where he's been shot down so often
he might as well be a Zero.
---

I ask because we have a lot of intellectually handicapped people
who could probably take your day job - and not pester the rest of us on
usenet with such friggin idiocy.

---
Too late, the guy's a remora...

JF

 

[John Fields]

On Fri, 05 Jun 2009 20:35:23 -0500, john joseph <nowhere@nowhere.nl>
wrote:

tgdenning@earthlink.net wrote:
On Jun 5, 7:28 pm, john joseph <nowh...@nowhere.nl> wrote:
tgdenn...@earthlink.net wrote:
On Jun 5, 3:02 pm, John Stafford <jstaff...@winona.edu> wrote:
On 6/5/09 1:26 PM, in article o6idnVqzaun2_rTXnZ2dnUVZ_gJi4...@giganews.com,
"Bill Ward" <bw...@ix.REMOVETHISnetcom.com> wrote:
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.
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?
True. Thanks for the affirmation, Bill.
But motors can be reversed, and so you can certainly come to a
complete stop using only the motors. However, as I said, there can be
a simple type of brake, since you need something for parking.
No they cannot! Not in real world applications! Try it! Try using only
engine braking. Engine braking has far more stopping potential than an
electric motor. But it still is far from enough!

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.

But they do not.

---
I'm not well versed in this field, so I'm asking: If the input to a DC
motor is shorted, once it's running, why would it take longer to stop it
than to run it up using a voltage source with a higher impedance than
the brake?
---

But the advantage of regenerative braking with four motors is that you
get smooth ABS when it matters----going from fast to very slow. You
*don't* need high-quality disc brakes---you could have a drum operated
by cable.
You are wrong, and now I understand that your automotive engineering
knowledge is just sheer impressionism.

No, I'm not wrong. Regenerative braking is a real effect, and with a
smart controller you will avoid losing traction.

You won't need a controller at all because at full-null input it still
will not have enough drag to cause the wheels to lock up.

I'm not saying it is a trivial matter to set up such a system but
there's nothing that prohibits it.

Oh, and cables stretch which is
why Volkswagen abandoned cable-actuated brakes in 1953. Catch up.

There are cables and there are cables. And we are not exerting tons of
force in this application.

Oh yes you are. Consider the diameter of the cable and the task it has
to perform. Same as the old VW Bugs which were still light.
JF

 

[Androcles]

<tgdenning@earthlink.net> wrote in message
news:00362541-e75b-4b96-a7a7-46ebe7a064b6@q14g2000vbn.googlegroups.com...
On Jun 5, 7:28 pm, john joseph <nowh...@nowhere.nl> wrote:

tgdenn...@earthlink.net wrote:
On Jun 5, 3:02 pm, John Stafford <jstaff...@winona.edu> wrote:
On 6/5/09 1:26 PM, in article
o6idnVqzaun2_rTXnZ2dnUVZ_gJi4...@giganews.com,

"Bill Ward" <bw...@ix.REMOVETHISnetcom.com> wrote:
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.
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?
True. Thanks for the affirmation, Bill.

But motors can be reversed, and so you can certainly come to a
complete stop using only the motors. However, as I said, there can be
a simple type of brake, since you need something for parking.

No they cannot! Not in real world applications! Try it! Try using only
engine braking. Engine braking has far more stopping potential than an
electric motor. But it still is far from enough!

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.

But the advantage of regenerative braking with four motors is that you
get smooth ABS when it matters----going from fast to very slow. You
*don't* need high-quality disc brakes---you could have a drum operated
by cable.

You are wrong, and now I understand that your automotive engineering
knowledge is just sheer impressionism.

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.

Oh, and cables stretch which is
why Volkswagen abandoned cable-actuated brakes in 1953. Catch up.

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!

I certainly understand that many of us would be nervous about driving
the first generation of completely brake-free cars,

Corvettes, and my builds, use fly-by-wire for throttle. No problem.
Catch up.

 

[Androcles]

"John Fields" <jfields@austininstruments.com> wrote in message
news:7lkj25hof1airoq6rgodu1reqcupd0rj3p@4ax.com...

On Fri, 05 Jun 2009 20:35:23 -0500, john joseph <nowhere@nowhere.nl
wrote:

tgdenning@earthlink.net wrote:
On Jun 5, 7:28 pm, john joseph <nowh...@nowhere.nl> wrote:
tgdenn...@earthlink.net wrote:
On Jun 5, 3:02 pm, John Stafford <jstaff...@winona.edu> wrote:
On 6/5/09 1:26 PM, in article
o6idnVqzaun2_rTXnZ2dnUVZ_gJi4...@giganews.com,
"Bill Ward" <bw...@ix.REMOVETHISnetcom.com> wrote:
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.
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?
True. Thanks for the affirmation, Bill.
But motors can be reversed, and so you can certainly come to a
complete stop using only the motors. However, as I said, there can be
a simple type of brake, since you need something for parking.
No they cannot! Not in real world applications! Try it! Try using only
engine braking. Engine braking has far more stopping potential than an
electric motor. But it still is far from enough!

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.

But they do not.

---
I'm not well versed in this field, so I'm asking: If the input to a DC
motor is shorted, once it's running, why would it take longer to stop it
than to run it up using a voltage source with a higher impedance than
the brake?
---
Huh?

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

But the advantage of regenerative braking with four motors is that you
get smooth ABS when it matters----going from fast to very slow. You
*don't* need high-quality disc brakes---you could have a drum operated
by cable.
You are wrong, and now I understand that your automotive engineering
knowledge is just sheer impressionism.

No, I'm not wrong. Regenerative braking is a real effect, and with a
smart controller you will avoid losing traction.

You won't need a controller at all because at full-null input it still
will not have enough drag to cause the wheels to lock up.

I'm not saying it is a trivial matter to set up such a system but
there's nothing that prohibits it.

Oh, and cables stretch which is
why Volkswagen abandoned cable-actuated brakes in 1953. Catch up.

There are cables and there are cables. And we are not exerting tons of
force in this application.

Oh yes you are. Consider the diameter of the cable and the task it has
to perform. Same as the old VW Bugs which were still light.
JF

 

[Androcles]

"Bret Cahill" <BretCahill@peoplepc.com> wrote in message
news:986994a1-00b8-49c0-9612-374a0c12950e@f19g2000yqo.googlegroups.com...

I'm not well versed in this field, so I'm asking: If the input to a DC
motor is shorted, once it's running, why would it take longer to stop it
than to run it up using a voltage source with a higher impedance than
the brake?
---

Huh?

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

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

John Fields has an IQ of 14.

His case worker keeps him posting here to keep him off the street.


Bret Cahill

Well, he did say he was asking and said he wasn't versed, so I went gentle .

 

[Bret Cahill]

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.

Motor/generators are transducers, not brakes. That means you can only
slow down, not come to a complete stop.

It's a good thing we have alert readers here to debunk regenerative
braking!

Regenerative braking can help if it is geared. Now go read up and come
back later, way later.

I was being funny. I don't use emocons.

How big a market do you expect for
cars without brakes?

Chrysler did pretty well with their Voyager. �When the ABS went out,
there was no backup.

.. . .

ABS works as a normal brake when the solenoid motor fails.

Not the Dodge minivan ABS system.

I actually rode around [in the desert w/ an excellent driver] in one
where the brakes were 99% gone.

In fact there is/was a 800 number somewhere where you could force any
Chrysler dealer anywhere to fix it for free.

They even had back up numbers in case the dealer didn't provide
satisfaction.

I was astounded that,

1. something that moronic could happen, and,

2. my used used car dealer acquaintence knew something that moronic
could happen.

How did he know?


Bret Cahill

 

[Bret Cahill]

I'm not well versed in this field, so I'm asking: If the input to a DC
motor is shorted, once it's running, why would it take longer to stop it
than to run it up using a voltage source with a higher impedance than
the brake?
---

Huh?

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

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

John Fields has an IQ of 14.

His case worker keeps him posting here to keep him off the street.


Bret Cahill

 

[Bret Cahill]

The reality is that if fuel goes to $15 per gallon there'll be an awful
lot of us working from home.

John Fields can provide the on line entertainment by claiming circular
furrows are impossible, that adiabatic engine systems might not scale
up . . .

And people who have to "be there" on the job,

If they want to get there they'll soon have to motor off the grid as
fuel costs have been increasing by 10% _a month_.

for example construction
workers (there will be construction)

We can only hope some will be working on getting energy to vehicles.

to plumbers and medics will be
making more money than egg heads.

Number crunching is so so so . . . gauche!.


Bret Cahill

 

[john joseph]

John Fields wrote:

On Fri, 05 Jun 2009 18:29:42 -0500, john joseph <nowhere@nowhere.nl
wrote:

Bret Cahill wrote:
Remember where Rhett manages to steal an old nag toward the end of the
Civil War?

Well, very soon we'll be similarly situated.

When fuel is $15/gallon a sled will be considered a nice ride.

We need to get back to reality:

I don't care if the vehicle has square wheels that don't turn we need
to focus on getting some kind of energy to the vehicle.
I'd like to know how you manage to feed and breathe - like you got a
job?

---
Yeah, he does.

He's some kind of a court reporter or legal assistant sissy or something
like that, and has delusions of adequacy which led him to start posting
his shit to sci.electronics.design, where he's been shot down so often
he might as well be a Zero.

Well them it is good that he's a zero - can't multiply.

 

[John Fields]

On Sat, 6 Jun 2009 03:47:58 +0100, "Androcles"
<Headmaster@Hogwarts.physics> wrote:

"John Fields" <jfields@austininstruments.com> wrote in message
news:7lkj25hof1airoq6rgodu1reqcupd0rj3p@4ax.com...
On Fri, 05 Jun 2009 20:35:23 -0500, john joseph <nowhere@nowhere.nl
wrote:

tgdenning@earthlink.net wrote:
On Jun 5, 7:28 pm, john joseph <nowh...@nowhere.nl> wrote:
tgdenn...@earthlink.net wrote:
On Jun 5, 3:02 pm, John Stafford <jstaff...@winona.edu> wrote:
On 6/5/09 1:26 PM, in article
o6idnVqzaun2_rTXnZ2dnUVZ_gJi4...@giganews.com,
"Bill Ward" <bw...@ix.REMOVETHISnetcom.com> wrote:
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.
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?
True. Thanks for the affirmation, Bill.
But motors can be reversed, and so you can certainly come to a
complete stop using only the motors. However, as I said, there can be
a simple type of brake, since you need something for parking.
No they cannot! Not in real world applications! Try it! Try using only
engine braking. Engine braking has far more stopping potential than an
electric motor. But it still is far from enough!

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.

But they do not.

---
I'm not well versed in this field, so I'm asking: If the input to a DC
motor is shorted, once it's running, why would it take longer to stop it
than to run it up using a voltage source with a higher impedance than
the brake?
---
Huh?
If you short any motor, AC or DC, it will stop faster than you can finish
the word "stop".

---
My point exactly, which was directed at the "But they do not."

[have as much 'stopping potential' as they have starting potential]

comment.

JF

 

On Jun 5, 9:35 pm, john joseph <nowh...@nowhere.nl> wrote:

tgdenn...@earthlink.net wrote:
On Jun 5, 7:28 pm, john joseph <nowh...@nowhere.nl> wrote:
tgdenn...@earthlink.net wrote:
On Jun 5, 3:02 pm, John Stafford <jstaff...@winona.edu> wrote:
On 6/5/09 1:26 PM, in article o6idnVqzaun2_rTXnZ2dnUVZ_gJi4...@giganews.com,
"Bill Ward" <bw...@ix.REMOVETHISnetcom.com> wrote:
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.
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?
True. Thanks for the affirmation, Bill.
But motors can be reversed, and so you can certainly come to a
complete stop using only the motors. However, as I said, there can be
a simple type of brake, since you need something for parking.
No they cannot! Not in real world applications! Try it! Try  using only
engine braking. Engine braking has far more stopping potential than an
electric motor. But it still is far from enough!

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.

But they do not.

Now you are being silly. Do you understand what reversing the motor
means?

-tg

But the advantage of regenerative braking with four motors is that you
get smooth ABS when it matters----going from fast to very slow.  You
*don't* need high-quality disc brakes---you could have a drum operated
by cable.
You are wrong, and now I understand that your automotive engineering
knowledge is just sheer impressionism.

No, I'm not wrong. Regenerative braking is a real effect, and with a
smart controller you will avoid losing traction.

You won't need a controller at all because at full-null input it still
will not have enough drag to cause the wheels to lock up.

I'm not saying it is a trivial matter to set up such a system but
there's nothing that prohibits it.

Oh, and cables stretch which is
why Volkswagen abandoned cable-actuated brakes in 1953. Catch up.

There are cables and there are cables. And we are not exerting tons of
force in this application.

Oh yes you are. Consider the diameter of the cable and the task it has
to perform. Same as the old VW Bugs which were still light.