Slotted Insulator To Electrify Field Tractors

That was pretty funny....

0.25 mile * √2 of something like 600 mcm wire to drag around (no, I didn't bother to calculate it), and then how many electric vs fuel tractors are there, anyway?

Well that's brightened up my morning

If you're really serious, I'd look into using a cable reel as is used in underground mining equipment. It would still pose problems--perhaps you'd have one permanent installation of a straight conductor in the middle of a field (basically bisecting the field) with multiple plug in connection / cable anchor points.

(The geometry is one of the interesting parts--you can't (don't want) the cable to drag across rows of crops--instead you want it to stay between rows--hence the multiple connection points. You might do two rows (that is, tractor widths) from each connection point, also working on both sides of that straight conductor in the middle of the field.)

You might also need higher voltages to get down to a reasonable conductor size. When I worked in (underground coal) mines, much of our AC equipment used 575 volts. I have a vague recollection that people were working towards using higher voltages, up towards 1000 volts.

That sounds scary, but they did (do) use quite a few safeguards to minimize the danger--ground current relays, ground check relays, etc.

Hmm, if you get into looking at mining equipment, as opposed to that fixed conductor down the center of a field, you might consider using a mining type (portable) power center supplied at an even higher voltage (4160, 7200) and move it forward (or backward) every two "tractor rows".

I suspect the whole thing would be quite expensive--I suspect it would not be cost effective. (Unless maybe you could buy used surplus equipment at low cost.) (But, I think one of these approaches will be less expensive than cables permanently installed in a field.)

If you do head in this direction, one thing you don't want to do is have equipment run over the cables. The cables usually survive being run over some number of times, but gradually suffer damage (broken conductors, compressed insulation), and, after not too much time, you have an expensive cable that needs to be replaced. (You can cut and splice the cable, but you're just prolonging the agony--avoid running over the cable.)

The slot cable would follow a diagonel path as it passes over the tractor, from, say, the right wheel rut in front of the tractor to the left wheel rut behind the tractor.

On each pass the tractor moves the cable over for the next pass as it works it way across the field.

The cable could easily be lifted over tall plants, even corn.

Unlike a strip mine farm fields here in the valley are almost all square and the operations are very predictable. With only 3" of rain/year all farm tractor operations are conducted on dry ground.

Many farmers would rather lose the crop than ruin their fields driving a tractor over them when they are wet.

Even when it does rain the soil is bone dry within 48 hours.

The cable handler on the tractor could include a brush to keep the slot and cable clean for muddy situations.

A reel like that used by strip mine operations isn't necessary or desirable but the comparison is useful.

A reel utilizes a circular slip ring to get the power from the rotating reel to a stationary motor, or at least a motor where the stator isn't rotating.

In some respects this would be a linear version of a slip ring with the "slip ring" distributed over the entire length of the cable.

Even in wet areas this may work.

8' florescent bulbs (~700 V) work even though a leaky roof is dripping water all over the ballast. 220 single phase ac motors seem to work just fine with somewhat caustic water sloshing over them.

Agriculture amounts to 6% of the petroleum consumed in the U. S. and will soon cost 100s of billions a year.

If anyone has a cheaper solution please post it.

Bret Cahill

If anyone has a cheaper solution please post it.

(modern) Diesel tractor by far, but that is not answering your original question which seems to be regarding switching away from fossil fuels like diesel. Perhaps running the engine on natural gas like LPG or CNG (conversion is necessary however).

If you wanted to go electric then the best way in my opinion would in fact be a full electric tractor with onboard batteries or a hybrid say battery/diesel system. Tethered systems and slip rings are problematic to say the least.

Either way, you still have to get the electricity from the grid, and the electricity is generated in the US using coal, oil, gas, nuclear, hydro, wind, solar, geothermal (I think that is fairly close to the correct order from highest to lowest power generation). You would effectively be trying to change from one fossil fuel to another.

Below is a current article that gives some numbers to what actually powers the American power grid, both now and in the foreseeable future.

http://intelligentenergyportal.com/article/where%E2%80%99s-energy-industry-heading-follow-money?cid=newsletter

Several weeks ago we looked at the U.S. Energy Information Agency (EIA) Annual Energy Outlook (2011) (see Climate Change, Renewables and Grain Ethanol: A Year End Dose of Reality) . The EIA analysis predicts that fossil fuels will continue to provide about three quarters of the electric energy supply for the next 25 years. Coal will continue to provide over 40 percent of supply.

Now there's an idea - why not burn the coal on-board the tractor?

Would save all that copper mining too.

I thought about that too, but it is rather a large progress step backwards (not to mention the pollution problems, especially for a farm growing food). Horse and plow would be a better alternative to a 'John Deere' Steam tractor.

I thought about that too, but wouldn't 150 horses just eat the harvest as they went?