300 kW EV Tractor vs 400 hp Diesel

[Bret Cahill]

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?

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]

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?

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 Fields]

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

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?

---
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.
---

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

---
I'm suggesting nothing but that your system is flawed.
---

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

---
Hmm... That's not much of a mantra.

JF

 

[John Fields]

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

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?

---
What makes you think it doesn't?
---

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

---
LOL, I'm not the one who keeps changing the subject.
---

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

---
What makes you think that I think that hybrids don't exist?
---

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

---
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.
---

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

---
Neither, of course, which escapes you because you're obviously
afflicted with the latter.

JF

 

[terryc]

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

"terryc" <newssixspam-spam@woa.com.au> wrote in message
newsan.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.

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.

The cable can be suspended far over ground close to the tractor (away

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?

A rotating multipole connecter should not be needed : a 1/2 mile cable
can handle a few 180's.

Lol.

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

 

[terryc]

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

What farmers really need are robot oxen.

<tic> Isn't that his solution? </tic>

 

[John Larkin]

On Tue, 29 Jul 2008 08:02:16 -0700 (PDT), disgoftunwells
<disgoftunwells@yahoo.co.uk> wrote:

On 26 Jul, 01:19, John Larkin
jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
On Fri, 25 Jul 2008 15:17:58 -0700 (PDT), disgoftunwells



disgoftunwe...@yahoo.co.uk> wrote:
On 23 Jul, 23:03, BretCah...@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.

Quite funny, but actually cable car tractors could be quite feasible
and low cost. They'd run on wheels - just be pulled from a fixed
motor, instead of from an oxen.

So instead of putting an engine on the tractor, you'd have it located
at the end of each (perfectly straight) row, pulling on a cable
attached to the tractor, somehow not tearing up the rows and the crops
between. And every time the tractor turns, the engine vehicle has to
move down one row, with nothing getting tangled. We'd make all the
rows somewhat shorter to allow for the extra machinery and maneuvering
room. Of course, the plowing patterns couldn't be a serpentine any
more - the cable doesn't allow that - but a comb shape, with a
plow-and-backtrack pattern for every row. That will take a little more
time (like, 2x), and will work fine as soon as you figure out how to
make a cable push as well as pull. [1]

We all know that farmers have a lot of spare time, so won't mind
increasing their plowing time by, say, 6:1 or so.

Besides, there's nothing new about engineers teaching farmers (dumb
one and smart ones) how to do it right. If they didn't, farmers would
still be using oxen.

The aggies of the nation thank you. [2]

John

[1] San Francisco's cable cars only go in one direction over each
slot. Maybe you could help them, too.

[2] Are you an engineer?

 

[disgoftunwells]

On 26 Jul, 01:19, John Larkin
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote:

On Fri, 25 Jul 2008 15:17:58 -0700 (PDT), disgoftunwells



disgoftunwe...@yahoo.co.uk> wrote:
On 23 Jul, 23:03, BretCah...@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.

Quite funny, but actually cable car tractors could be quite feasible

and low cost. They'd run on wheels - just be pulled from a fixed
motor, instead of from an oxen.

Besides, there's nothing new about engineers teaching farmers (dumb
one and smart ones) how to do it right. If they didn't, farmers would
still be using oxen.

 

[Mark Thorson]

John Larkin wrote:

So instead of putting an engine on the tractor, you'd have it located
at the end of each (perfectly straight) row, pulling on a cable
attached to the tractor, somehow not tearing up the rows and the crops
between. And every time the tractor turns, the engine vehicle has to
move down one row, with nothing getting tangled. We'd make all the
rows somewhat shorter to allow for the extra machinery and maneuvering
room. Of course, the plowing patterns couldn't be a serpentine any
more - the cable doesn't allow that - but a comb shape, with a
plow-and-backtrack pattern for every row. That will take a little more
time (like, 2x), and will work fine as soon as you figure out how to
make a cable push as well as pull. [1]

It's called a "ploughing engine". They were used
in the days of steam.

http://en.wikipedia.org/wiki/Traction_engine#Ploughing_engine

They were used in pairs, one on each side of the field.

 

[Mark]

re cables to power electric tractors...


see "center pivot irrigation"


If they can do this, they can figure out how to get a cable to a
tractor.

Mark

 

[disgoftunwells]

On 29 Jul, 16:23, John Larkin
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote:

On Tue, 29 Jul 2008 08:02:16 -0700 (PDT), disgoftunwells



disgoftunwe...@yahoo.co.uk> wrote:
On 26 Jul, 01:19, John Larkin
jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
On Fri, 25 Jul 2008 15:17:58 -0700 (PDT), disgoftunwells

disgoftunwe...@yahoo.co.uk> wrote:
On 23 Jul, 23:03, BretCah...@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.

Quite funny, but actually cable car tractors could be quite feasible
and low cost. They'd run on wheels - just be pulled from a fixed
motor, instead of from an oxen.

So instead of putting an engine on the tractor, you'd have it located
at the end of each (perfectly straight) row, pulling on a cable
attached to the tractor, somehow not tearing up the rows and the crops
between. And every time the tractor turns, the engine vehicle has to
move down one row, with nothing getting tangled. We'd make all the
rows somewhat shorter to allow for the extra machinery and maneuvering
room. Of course, the plowing patterns couldn't be a serpentine any
more - the cable doesn't allow that - but a comb shape, with a
plow-and-backtrack pattern for every row. That will take a little more
time (like, 2x), and will work fine as soon as you figure out how to
make a cable push as well as pull. [1]

Thanks to Mark Thorson for pointing out this was done a long time ago.

The optimum way to plough a field is influenced by the relative values
of fuel costs, labour costs, equipment costs, yield levels.

Fuel has been rather cheap over the last 100 years or so. as it gets
more expensive methods may change.

The technique above would work best with longer rows, with the plough
or harvester running between two movable points. No reason why it
can't be just as fast as normal ploughing, with less room required for
the wheels.

Probably works best on large prarie fields.

We all know that farmers have a lot of spare time, so won't mind
increasing their plowing time by, say, 6:1 or so.

6:1? Why not make it 100:1?

I would have thought sitting in a control centre controlling multiple
units would be faster. Actually, farm labour must be cheap otherwise
most of this would have automated long ago. Or at least remote
controlled.

Besides, there's nothing new about engineers teaching farmers (dumb
one and smart ones) how to do it right. If they didn't, farmers would
still be using oxen.

The aggies of the nation thank you. [2]

John

[1] San Francisco's cable cars only go in one direction over each
slot. Maybe you could help them, too.

They're a tourist attraction, not an efficient people mover.

Are you an engineer?

Yes

 

[Bret Cahill]

re cables to power electric tractors...

see ďż˝"center pivot irrigation"

If they can do this, they can figure out how to get a cable to a
tractor.
I agree. I posted some specific figures to prove the basic practicality of
using a "low voltage" 480 VAC 3 phase service cable that can drive at least
a 100 HP electric motor on a 250 ft pivot arm, and with a bit of
"Enginuity" a system could be rigged up where the tractor could have more
degrees of freedom than a circular path, if needed.

Farmers seem to be competent at dealing with all kinds of Rube
Goldberg impliments.

Even so KISS should prevail. A pivot could run unattended at night
moving the drive wheels and impliments radially for a spiral furrow.

Figuring out the details, building a prototype, and doing some actual field
testing would be a fascinating and worthwhile challenge, probably well
suited to a college with agricultural and engineering departments.

An ag extension center.


Bret Cahill

 

[Bret Cahill]

see ďż˝"center pivot irrigation"

If they can do this, they can figure out how to get a cable to a
tractor.

I posted the "super pivot" on sci.energy last summer. The idea was to
get rid of the tractor altogether, just keep the wheels motor and the
impliments.

A conventional pivot moves pretty slow so the super pivot could have
several concentric areas so the tangential velocity wouldn't vary too
much from the outer "tip speed" to the inner "boss."

A poster claiming to be from Nebraska said a conventional pivot sells
for $45,000, a pretty good deal considering the distance it spans. In
something like a berry field it would pay for itself in a matter of
months.

A pivot, however, requires flat land and some of the square field is
"wasted." Moreover, a grid-battery tractor is the cheapest way to get
the foot in the E feld door.

One wire.

One battery.

One tractor with the diesel replaced with an electric motor.

Do that first _then_ you can get fancy.


Bret Cahill

 

[Dean Hoffman]

Mark wrote:

re cables to power electric tractors...


see "center pivot irrigation"


If they can do this, they can figure out how to get a cable to a
tractor.

Mark

There's a world of difference in the power requirements. Center
pivot motors are three phase 480 in the U.S. The older ones used either
a single one horsepower motor or a horse and a half motor. The newer
ones use motors half that size. The older ones had 10 AWG Cu in the
span cable to power the pivots that were 1/4 mile long. The newer ones
can get by with 12 AWG Cu to power the motors.
Tractors in my area are probably in the range of 150 to 200
horsepower or so. Front wheel assist with duals rather than the four
wheelers Brett talks about.
Take a 100 horsepower irrigation well motor with a pivot. A
quarter mile run from the power supply to the center point where the
well might be. That would take 250 or 350 MCM aluminum wire depending
on the voltage drop one wants.
You'd have to double the distance and double the amperage to make a
200 horsepower tractor run at the far end of the pivot.
Then there would be the problem of getting the power to the fields
in the first place. Power companies probably wouldn't be all that eager
to put up lines that would be needed only part of the time.
Most of the irrigation wells in my area are on interruptible power.
The suppliers can shut them off by remote control if the load gets
too heavy from other uses. Thats fine for irrigation but probably not
for field operations that need to get done in a timely manner.

Dean


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[Dean Hoffman]

Dean Hoffman > wrote:

Mark wrote:
re cables to power electric tractors...


see "center pivot irrigation"


If they can do this, they can figure out how to get a cable to a
tractor.

Mark

There's a world of difference in the power requirements. Center
pivot motors are three phase 480 in the U.S. The older ones used either
a single one horsepower motor or a horse and a half motor. The newer
ones use motors half that size. The older ones had 10 AWG Cu in the
span cable to power the pivots that were 1/4 mile long. The newer ones
can get by with 12 AWG Cu to power the motors.
A little correction. That would be one motor per tower. Circle

pivots usually have 7, 8, or sometimes 10 towers for a 1300 foot
machine. More drive units are needed for rougher ground.

Tractors in my area are probably in the range of 150 to 200
horsepower or so. Front wheel assist with duals rather than the four
wheelers Brett talks about.
Take a 100 horsepower irrigation well motor with a pivot. A
quarter mile run from the power supply to the center point where the
well might be. That would take 250 or 350 MCM aluminum wire depending
on the voltage drop one wants.
You'd have to double the distance and double the amperage to make a
200 horsepower tractor run at the far end of the pivot.
Then there would be the problem of getting the power to the fields
in the first place. Power companies probably wouldn't be all that eager
to put up lines that would be needed only part of the time.
Most of the irrigation wells in my area are on interruptible power.
The suppliers can shut them off by remote control if the load gets too
heavy from other uses. Thats fine for irrigation but probably not for
field operations that need to get done in a timely manner.

Dean


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[Bret Cahill]

re cables to power electric tractors...

see ďż˝"center pivot irrigation"

If they can do this, they can figure out how to get a cable to a
tractor.

ďż˝ ďż˝ ďż˝ There's a world of difference in the power requirements. ďż˝

The real concern is how to manage the cable. The appeal of straight
grid is undeniable: Grid is only _one fourth_ the cost of diesel and
"dropping."

Grid-battery is now about 3/4ths the cost of diesel but it's dropping
just as fast.

On the other hand, while farmers are pretty good at dealing with Rube
Goldberg contraptions -- some of the impliments need to be in horror
movies -- I look at a field and think, "no way I'm gonna pry a farmer
from his water wars to adopt Etch O Sketch kinematics."

Center
pivot motors are three phase 480 in the U.S. �The older ones used either
a single one horsepower motor or a horse and a half motor. �The newer
ones use motors half that size. �The older ones had 10 AWG Cu in the
span cable to power the pivots that were 1/4 mile long. �The newer ones
can get by with 12 AWG Cu to power the motors.

A heavier gauge cable isn't going to crush the pivot.

� � �Tractors in my area are probably in the range of 150 to 200
horsepower or so. �Front wheel assist with duals rather than the four
wheelers Brett talks about.
� � �Take a 100 horsepower irrigation well motor with a pivot. �A
quarter mile run from the power supply to the center point where the
well might be. �That would take 250 or 350 MCM aluminum wire depending
on the voltage drop one wants.

They still use diesel irrigation pumps here. A crop insurance
adjuster assures me that they use diesel pumps in Florida as well.

Saturday I was out cycling and passed a field irrigated with miles of
aluminum pipe and a gazillion sprinklers being pumped by a diesel 30
feet from a power line.

Now _that_ would be easy.

ďż˝ ďż˝ You'd have to double the distance and double the amperage to make a
200 horsepower tractor run at the far end of the pivot.

OK.

� � �Then there would be the problem of getting the power to the fields
in the first place. �Power companies probably wouldn't be all that eager
to put up lines that would be needed only part of the time.

I can't even get UP to save $2.5 billion a year in diesel by
electrifying their main line in the desert.

Railroads are a much more obvious candidate than farms.

ďż˝ ďż˝ Most of the irrigation wells in my area are on interruptible power.
� �The suppliers can shut them off by remote control if the load gets
too heavy from other uses. �Thats fine for irrigation but probably not
for field operations that need to get done in a timely manner.

Place Sandia dishes or PV in the "corners" clipped off by the circular
field.


Bret Cahill

 

[John Fields]

On Tue, 29 Jul 2008 17:48:01 -0700 (PDT), Bret Cahill
<BretCahill@aol.com> wrote:

see ?"center pivot irrigation"

If they can do this, they can figure out how to get a cable to a
tractor.

I posted the "super pivot" on sci.energy last summer. The idea was to
get rid of the tractor altogether, just keep the wheels motor and the
impliments.

A conventional pivot moves pretty slow so the super pivot could have
several concentric areas so the tangential velocity wouldn't vary too
much from the outer "tip speed" to the inner "boss."

A poster claiming to be from Nebraska said a conventional pivot sells
for $45,000, a pretty good deal considering the distance it spans. In
something like a berry field it would pay for itself in a matter of
months.

A pivot, however, requires flat land and some of the square field is
"wasted." Moreover, a grid-battery tractor is the cheapest way to get
the foot in the E feld door.

One wire.

One battery.

One tractor with the diesel replaced with an electric motor.

Do that first _then_ you can get fancy.

---
So get off your fat, lazy ass and do it instead of running your mouth.

JF

 

[Eeyore]

Bret Cahill wrote:

I can't even get UP to save $2.5 billion a year in diesel by
electrifying their main line in the desert.

How long is the line ?

Any idea how much it costs to electrifiy a line ?

Graham

 

[Mark]

On Jul 29, 10:49 pm, Dean Hoffman <""dh0496\"@ine$br#as&ka.com">
wrote:

Mark wrote:
re cables to power electric tractors...

see  "center pivot irrigation"

If they can do this, they can figure out how to get a cable to a
tractor.

Mark

      There's a world of difference in the power requirements.   Center
pivot motors are three phase 480 in the U.S.  The older ones used either
a single one horsepower motor or a horse and a half motor.  The newer
ones use motors half that size.  The older ones had 10 AWG Cu in the
span cable to power the pivots that were 1/4 mile long.  The newer ones
can get by with 12 AWG Cu to power the motors.

I'm sorry you missed my point.

My point is not about the amount of power needed to run the
irrigators vs a tractor... My point was, if a machine can be
designed to distribute WATER through a PIPE to a large circular area
like that, then a similar machine can be designed to distribute a
power cable to a tractor over a similarly large area.

Mark

 

[John Fields]

On Wed, 30 Jul 2008 07:28:56 -0700 (PDT), Bret Cahill
<BretCahill@aol.com> wrote:

see ?"center pivot irrigation"

If they can do this, they can figure out how to get a cable to a
tractor.

I posted the "super pivot" on sci.energy last summer. ?The idea was to
get rid of the tractor altogether, just keep the wheels motor and the
impliments.

A conventional pivot moves pretty slow so the super pivot could have
several concentric areas so the tangential velocity wouldn't vary too
much from the outer "tip speed" to the inner "boss."

A poster claiming to be from Nebraska said a conventional pivot sells
for $45,000, a pretty good deal considering the distance it spans. ?In
something like a berry field it would pay for itself in a matter of
months.

A pivot, however, requires flat land and some of the square field is
"wasted." ?Moreover, a grid-battery tractor is the cheapest way to get
the foot in the E feld door.

One wire.

One battery.

One tractor with the diesel replaced with an electric motor.

Do that first _then_ you can get fancy.

---
So get off your fat, lazy ass and do it instead of running your mouth.

Cite?

Show your calculations.

Totally huge.

---
http://en.wikipedia.org/wiki/Apoplexy#Non-medical_usage

LOL!
JF