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terryc · Guest

On Sat, 26 Jul 2008 02:13:15 +0100, Eeyore wrote:

[quote]

But not always possible. I mean what grade of sheath wouls such a cable require
[/quote]
Stuff would already exist in the mining industry. The farmer would just
need a crane to connect and disconnect it. It is the rotating multipole
connector that has me intrigued

[quote]? And concentric circles IS NOT how farmers like to work fields for what I hope
are obvious reasons. How about the getting into the 'corners' ?
[/quote]
He is avoiding all those problems by talking about mythical flat land
where you do not have corners in irrigation bays, etc.

terryc · Guest

On Sat, 26 Jul 2008 02:17:42 +0100, Eeyore wrote:

[quote]Hey, I>ll give you 'neat idea' tick bit I cannot for the life of me ever see it being engineeringly practical (not to mention killing
thousands of farm workers every year too).
[/quote]
something much worse. Ever been down an underground mine with electrically
operated shuttle cars.

""Make sure that when ever you have to cross a shuttle car cable that you
step onto the cable and not over it"
Why?
"You don>t want to know"

Day Brown · Guest

Might wanna take a look at http://daybrown.org/farmath/farmath.html
A team of oat burners will pull a moldboard plow at 5mph, covering about
7.5 acres/day. Mite try 3 oxen with a double bottom at 3mph, but get
10 acres/day. And oxen dont need oats.

If the proverbial schitt hits the fan, I>m gonna walk into a pasture
with a hatfull of corn, and walk out with oxen following me cause they
dont mind me stroking them while they eat, and they want more.

There are also horses that still have the full set of instincts to be
worked as draft animals. Right now, one farmer grows enuf food for 100
people. With draft animals, one feeds 25. That>s still not that bad, and
its a system that has worked for thousands of years.

With diesel and petrochemicals, they expect 155 bu corn/acre. Farmath,
in 1885, got only 21 bu corn. But, I was born on a farm, and remember
draft animals getting 45-48 bu/acre with what we now call 'organic'
methods using better hybrid seed. And it aint that hard to produce the
hybrid seed with organic methods.

BTW: a problem with the high density NiMH is that you can f ck them up
if they are not charged at the right rate and then turned off. The
technology with draft animals could be looked into to dramatically
improve production.

Worth considering also is using 3.5 gallons of tractor fuel to grow
sorghum, which will produce 100-120 gallons of ethanol, which can then
be converted into butanol. Which will run any gas engine without any
modification at the same power output.

John Larkin · Guest

On Sat, 26 Jul 2008 02:47:35 +0100, Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:

[quote]

John Larkin wrote:

disgoftunwells wrote:
OBretCah...@peoplepc.com wrote:
The Tesla is powered by 7,000 Li-Ion laptop batteries for an output of
200 kW.

A similarly powered 300 kW electric tractor (10,500 batteries) would
turn a 400 hp articulated 22 gallon/hour diesel tractor every which
way but loose in a tractor pull which apparently is vitally necessary
education as well as entertainment for those too ignorant do basic
IEOR calculations.

Running either tractor wide open to work a square mile at 0.5 mph
would take 3 months of 7 day work weeks at 8 hours / day.

It would also require 17,000 gallons of diesel.

Today the cost is "only" $80,000 for the diesel.

In 2 years, with the price of hydrocarbon fuel spiraling by 30% a
year, that cost will be $150,000/yr.

In six years the cost of the fuel will be half a million dollars.

And that>s just for one field.

Maybe if we have massive truck and bus conversion to natural gas --
include farm tractors in Pickens plan -- the price will "only" be
$350,000/field in 6 years.

The battery tractor would be cheaper even if grid power tripled and
even if you went to your overpriced Apple Inc. store and bought the
batteries one by one and wired them together one by one yourself.

Now, if you don>t believe laptop batteries exist, please go to alt.
conspiracy and post there.

Bret Cahill

I>ve read that over time, crop fields suffer from the compression of
tractor wheels.

Would it make sense, for heavily utilised fields, to lay down a rail
track?

Whatever the tractor / harvester is doing, it could be a 20m wide
vehicle necessitating a single track spaced every 20m.

The track could also be used to provide electric power.

A few details to work out about how the tractor changes track at the
end of the rails.

Why not monorails in all the cornfields? Then the electric power
could be provided by the rail, and there would be zero unnecessary
contact with the soil. And you could give tourists rides in the off
season.

Or just use nuclear powered helicopters for plowing; as a bonus,
they>d blow the bugs away, and irradiate the produce.

I you bury superconductors under the crop rows, you could use a maglev
tractor. Put Luke Skywalker back on the farm.

Or the San Francisco farming technique, cable-car tractors. No power
needed at all!

We>ll teach all those dumb farmers how to do it right.

When I read the first line of your post, for a second I wondered in you>d had
some psychotic episode.
[/quote]
I have psychotic episodes daily, or more often for difficult projects.

Often we>ll go into the conference room and do it as a departmental
activity. The whiteboards get positively psychedelic.

Bret has two problems: he>s fixated on a single solution, and he
understands neither the application nor the technology. He>s crazier
than I am.

What farmers really need are robot oxen.

John

Bret Cahill · Guest

[quote]Losses aren>t an issue.
[/quote]
.. . .

[quote]Why else do you think long-haul transmission lines use high voltages
to move electricity around?
[/quote]
Because they are long haul, over a hundred miles in many cases. The
quarter square tractor trolly line only needs to go half a mile.

Are you just acting dumb or are you really this stupid in real life?

Bret Cahill

Bret Cahill · Guest

[quote]Losses aren>t an issue.

I just love the stuff you come up with !

Graham

I>d like to know what he thinks losses are.

Losses are always part of the equation, but a reasonably well engineered
system might be rather efficient even using "low voltage" cable. For
something like 90 HP, or 66 kW, a three phase 480 VAC supply at 80 amps per
phase could use #2 portable cordage. A 250 foot length is $14.49/ft, so you
are looking at a capital outlay of $3600 to allow the tractor to traverse a
circular field of 200,000 square feet, or about 5 acres. It would need to
be stowed on the tractor on a reel, and supported to its central connection
point on a pivot arm. This #2 cable has a resistance of 156 uOhms per foot,
so at 80 amps it will drop 3.12 volts out of 277, or roughly 1% loss. Even
a 1000 ft cable would still have acceptable losses, compared to efficiency
of the electric motor and distribution transformer at the central supply
point.

For higher HP ratings, multiple cables could be used, but I think a 90 HP
electric tractor is probably equivalent to a a 150 HP diesel, and you just
need to look at actual needs of torque and speed, which determine the HP
required.

There will probably be more losses with a hybrid system that uses 8000
batteries or the equivalent in battery packs. A mostly grid-powered system
is feasible using current technology, and should reap almost immediate cost
savings, or ROI within a few years.

But every objection to a proposed improvement is just an engineering
challenge that promotes thought and new ideas that can be shown to address
the problems and provide a workable solution. Almost every new technology
seems to be impractical or awkward in its infancy, but innovation prevails,
and changing economic realities make the future a different place.
[/quote]
Well we know oil is spiraling and we know and PV is going down in
cost. We also know that batteries are continually improving. If not
now then well before the first prototype electric field tractor ever
appears it will _already_ be cost effective in most regions.

Having a source of power that is always very close to a moving
electric motor means even low power density storage devices such as
compressed air, flywheels or capacitors might be considered within
reach.

This is the real advantage of electric tractors over hybrid road
vehicles.

[quote]Yet I can see that much of this discussion has degraded to a battle among
several narrow-minded viewpoints, and that will serve no useful purpose.
[/quote]
The real problems to be solved are either identical to the hybrid or
EV, i. e., cheap good battery, a materials problem, or unique to
argicultural operations, i. e., electric power is always within a
relatively short distance of the tractor or some combination those
two.

Everything else is white noise.

Bret Cahill

Bret Cahill · Guest

[quote]The cable needs to be rolled and unrolled on the center pivot beam, so it
never even touches the ground.
[/quote]
Strip mine excavators roll a 6" thick insulated cable on the ground
from a spool mounted on the excavator.

The excavator moves very slowly and only makes one pass or so over the
ground, however.

[quote]The tractor can support part of the beam and
can pivot at various angles so it can traverse the field with some freedom
of motion, but its best path will be concentric circles. It will be some
tricky engineering to allow the tractor to pass the other support/drive
wheels for the beam, but challenges like that are what make engineering
fun.
[/quote]
The fastest cheapest easiest _prototype_ to get your foot into the
door would be the battery-trolly line. If a cheap battery didn>t
appear in time, then the system would be abandoned at the state U>s
extension research farm.

After that then maybe it will be possible to talk farmers into
screwing around with a lot of wires and Rube Goldberg kinematics.

Bret Cahill

Bret Cahill · Guest

[quote]But not always possible. I mean what grade of sheath wouls such a cable
require

Stuff would already exist in the mining industry. The farmer would just
need a crane to connect and disconnect it. It is the rotating multipole
connector that has me intrigued

? And concentric circles IS NOT how farmers like to work fields for what
I hope
are obvious reasons. How about the getting into the 'corners' ?

He is avoiding all those problems by talking about mythical flat land
where you do not have corners in irrigation bays, etc.

Guys, show a little bit of imagination and engineering inginuity please.
After all, we wanted to get rid of the battery idea (gaining efficiency, and
most of all difficult recharges).

The cable can be suspended far over ground close to the tractor (away from
the moving parts), maybe even all the way across the field using a system of
overhead arms or small computer-controlled robot 'cable-suspension' cars.

A rotating multipole connecter should not be needed : a 1/2 mile cable can
handle a few 180>s.
[/quote]
Even high tension towers are only spaced 1/4 mile apart. I use them
to triangulate my distance cycling.

On a battery basis, 1/2 a mile is a short distance. On a cable basis
it>s a long distance.

[quote]Also, the time is here that plowing (or seeding or so) no nonger needs a
human on the tractor. Much is being computerized, running the tractor on
pre-programmed patterns using GPS and such, so that effiency is maximized.
Even work at night is then possiible (which also reduces the machinery
deficit that seems to plague harvest time). So, you can simply program the
pattern so that 'twisting' the wire is not an issue.
[/quote]
The fastest cheapest easiest _prototype_ to get your foot into the
door would be the battery-trolly line. If a cheap battery didn>t
appear in time, then the system would be abandoned at the state U>s
extension research farm.

After that then maybe it will be possible to talk farmers into
screwing around with a lot of wires and Rube Goldberg kinematics.

Bret Cahill

Bret Cahill · Guest

[quote]That>s the point of the trolly wire. ?The size of the battery can be
reduced by 1 - 2 orders of magnitude because, unlike an EV or plug in,
the tractor charges up every 6 - 10 minutes, after each pass.

Bret, if the tractor goes (what was it?) 1 mph or so, and it needs 10 minutes for one pass (5 min each way), then the field is no
wider than 440 feet.

Is that a reasonable assumption ?

No. �As one poster citing government and industry material pointed
out, tractors generally go much faster.

If so, why not just use a high-voltage extension cable ?

Another moveable wire off of the stationary wire?

Actually, a 10kV line can be miles long without too many losses (for the 300 kW that you need).

Losses aren>t an issue.

---
Really?

Let>s say you need 400HP out of a motor which is 90% efficient and
that the input voltage to the motor comes from a PWM controller which
is also 90% efficient and which is driven with a battery with a
charge-to-discharge efficiency of 90%.

That means the efficiency, from battery to motor shaft will be:

� � �Et = E1E2E3 = 0.9 * 0.9 * 0.9 = 0.729 ~ 73%
[/quote]
Not that your numbers are any good -- electric motors are 95%
efficient and don>t need to "idle" at the end of the field for 15
minutes while the farmer gets ready for the next pass -- but what is
the conclusion when the cost of diesel goes up 30% a year, more than
enough to wipe out the 27% loss?

Are you suggesting we should wait another year before designing the
system?

Are you just acting dumb or are you really this stupid in real life?

Bret Cahill

Bret Cahill · Guest

[quote]That>s the point of the trolly wire. ?The size of the battery can be
reduced by 1 - 2 orders of magnitude because, unlike an EV or plug in,
the tractor charges up every 6 - 10 minutes, after each pass.

Bret, if the tractor goes (what was it?) 1 mph or so, and it needs 10 minutes for one pass (5 min each way), then the field is no
wider than 440 feet.

Is that a reasonable assumption ?

No. �As one poster citing government and industry material pointed
out, tractors generally go much faster.

If so, why not just use a high-voltage extension cable ?

Another moveable wire off of the stationary wire?

Actually, a 10kV line can be miles long without too many losses (for the 300 kW that you need).

Losses aren>t an issue.

---
Really?

Let>s say you need 400HP out of a motor which is 90% efficient and
that the input voltage to the motor comes from a PWM controller which
is also 90% efficient and which is driven with a battery with a
charge-to-discharge efficiency of 90%.

That means the efficiency, from battery to motor shaft will be:

� � �Et = E1E2E3 = 0.9 * 0.9 * 0.9 = 0.729 ~ 73%
[/quote]
Why doesn>t this apply to hybrid road motor vehicles?

You keep dodging that issue and you expect to get better results.

If you are incapable of reasoning and facing the reality that hybrids
exist, then all the "calculations" in the world are useless.

You were doing just as good using the word "huge."

Are you just acting stupid or are you really this dumb in real life?

Bret Cahill

John Larkin · Guest

On Sat, 26 Jul 2008 14:39:03 -0700 (PDT), Bret Cahill
<BretCahill@aol.com> wrote:

[quote]Losses aren>t an issue.

. . .

Why else do you think long-haul transmission lines use high voltages
to move electricity around?

Because they are long haul, over a hundred miles in many cases. The
quarter square tractor trolly line only needs to go half a mile.
[/quote]
Half a mile from where? An electrical outlet conveniently located in
the middle of 800 acres of corn field?

[quote]
Are you just acting dumb or are you really this stupid in real life?

[/quote]
Please refresh us on your background in electrical engineering, and in
farming.

John

terryc · Guest

On Sat, 26 Jul 2008 09:08:05 -0700, John Larkin wrote:

[quote]What farmers really need are robot oxen.
[/quote]
<tic> Isn>t that his solution? </tic>

terryc · Guest

On Fri, 25 Jul 2008 22:43:42 -0700, Rob Dekker wrote:

[quote]
"terryc" <newssixspam-spam@woa.com.au> wrote in message
news:pan.2008.07.26.03.17.25.737139@woa.com.au...
On Sat, 26 Jul 2008 02:13:15 +0100, Eeyore wrote:

But not always possible. I mean what grade of sheath wouls such a cable
require

Stuff would already exist in the mining industry. The farmer would just
need a crane to connect and disconnect it. It is the rotating multipole
connector that has me intrigued

? And concentric circles IS NOT how farmers like to work fields for what
I hope
are obvious reasons. How about the getting into the 'corners' ?

He is avoiding all those problems by talking about mythical flat land
where you do not have corners in irrigation bays, etc.

Guys, show a little bit of imagination and engineering inginuity please.
[/quote]
The problem here is far too much imagination and far too little
perspiration. If you want people with the ability to provide the
perspiration, then you need to show
a) that you are willing to listen
b) you have enough education to justify people making the effort of
pointing out the flaws.

[quote]The cable can be suspended far over ground close to the tractor (away
[/quote]
Oh look, magical sky hooks.

When I was young, fit and stupid and could lift 20' of 2' greentree
trunks, I struggled to lift the electrical power cable for a continous
miner to waist height. It was typically a job for three strong men.

Do you begin to comprehend why those of us with a clue are ROTFL?

[quote]A rotating multipole connecter should not be needed : a 1/2 mile cable
can handle a few 180>s.
[/quote]
Lol.

damm, snipped the "software solution to a techncal problem". That attitude
is what is fscking linux.

John Fields · Guest

On Sat, 26 Jul 2008 15:47:12 -0700 (PDT), Bret Cahill
<BretCahill@aol.com> wrote:

[quote]That>s the point of the trolly wire. ?The size of the battery can be
reduced by 1 - 2 orders of magnitude because, unlike an EV or plug in,
the tractor charges up every 6 - 10 minutes, after each pass.

Bret, if the tractor goes (what was it?) 1 mph or so, and it needs 10 minutes for one pass (5 min each way), then the field is no
wider than 440 feet.

Is that a reasonable assumption ?

No. ?As one poster citing government and industry material pointed
out, tractors generally go much faster.

If so, why not just use a high-voltage extension cable ?

Another moveable wire off of the stationary wire?

Actually, a 10kV line can be miles long without too many losses (for the 300 kW that you need).

Losses aren>t an issue.

---
Really?

Let>s say you need 400HP out of a motor which is 90% efficient and
that the input voltage to the motor comes from a PWM controller which
is also 90% efficient and which is driven with a battery with a
charge-to-discharge efficiency of 90%.

That means the efficiency, from battery to motor shaft will be:

? ? ?Et = E1E2E3 = 0.9 * 0.9 * 0.9 = 0.729 ~ 73%

Why doesn>t this apply to hybrid road motor vehicles?
[/quote]
---
What makes you think it doesn>t?
---

[quote]You keep dodging that issue and you expect to get better results.
[/quote]
---
LOL, I>m not the one who keeps changing the subject.
---

[quote]If you are incapable of reasoning and facing the reality that hybrids
exist, then all the "calculations" in the world are useless.
[/quote]
---
What makes you think that I think that hybrids don>t exist?
---

[quote]You were doing just as good using the word "huge."
[/quote]
---
Just as _well_, and the way I used it was appropriate in the context
in which it was being used. You, of course railed against it just to
buy some time and to throw a little more shit into the game.
---

[quote]Are you just acting stupid or are you really this dumb in real life?
[/quote]
---
Neither, of course, which escapes you because you>re obviously
afflicted with the latter.

JF

John Fields · Guest

On Sat, 26 Jul 2008 15:42:52 -0700 (PDT), Bret Cahill
<BretCahill@aol.com> wrote:

[quote]That>s the point of the trolly wire. ?The size of the battery can be
reduced by 1 - 2 orders of magnitude because, unlike an EV or plug in,
the tractor charges up every 6 - 10 minutes, after each pass.

Bret, if the tractor goes (what was it?) 1 mph or so, and it needs 10 minutes for one pass (5 min each way), then the field is no
wider than 440 feet.

Is that a reasonable assumption ?

No. ?As one poster citing government and industry material pointed
out, tractors generally go much faster.

If so, why not just use a high-voltage extension cable ?

Another moveable wire off of the stationary wire?

Actually, a 10kV line can be miles long without too many losses (for the 300 kW that you need).

Losses aren>t an issue.

---
Really?

Let>s say you need 400HP out of a motor which is 90% efficient and
that the input voltage to the motor comes from a PWM controller which
is also 90% efficient and which is driven with a battery with a
charge-to-discharge efficiency of 90%.

That means the efficiency, from battery to motor shaft will be:

? ? ?Et = E1E2E3 = 0.9 * 0.9 * 0.9 = 0.729 ~ 73%

Not that your numbers are any good -- electric motors are 95%
efficient and don>t need to "idle" at the end of the field for 15
minutes while the farmer gets ready for the next pass -- but what is
the conclusion when the cost of diesel goes up 30% a year, more than
enough to wipe out the 27% loss?
[/quote]
---
I>ve given you the method which will allow you to figure it out for
yourself, so plug your numbers into it and figure it out and stop
asking stupid questions.

Plus, you have no idea where diesel will go or if it>ll be replaced by
other liquid fuels, so all you>re doing is pissing in the wind,
pretending to know what you>re talking about.
---

[quote]Are you suggesting we should wait another year before designing the
system?
[/quote]
---
I>m suggesting nothing but that your system is flawed.
---

[quote]Are you just acting dumb or are you really this stupid in real life?
[/quote]
---
Hmm... That>s not much of a mantra.

JF


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