Cord Management on Grid-Connected Electric Tractors and Mobile Equipment

[Phil Timmons]

I suppose most here are familiar with various designs using batteries. However, these have some limitations of expense, weight, limited service life, and run and charge times.

A way to avoid the battery issues is to use Grid-Connected designs. This allows the Grid-Connected equipment unlimited run time, longer service life, as well as no battery related expense.

Have worked out some Center-Pivot style Electric Designs. Those are fairly easy, as the Center of the Pivot has an Electric Supply, and electric drive wheels all the way down the towers -- so this provides Grid-Connected electricity to the entire field.

But when you get into irregular field shapes, things can get a bit more complex. Looking at using Cord Connections for these, and looking at the Cord Management involved.

John Deere has their approach shown here >>>

However, their approach -- with a kilometer of cord, and the complex reel system adds about as much expense as batteries.

One approach is to use a side-of-the-field connection approach, and allow the cord to sweep along beside the equipment while you work your way across the field, and another approach is to use a center-of-the field connection approach and spiral in or out from this center.

Attached are a couple of very simplified sketches on a sample one acre square. Of course, practical irregular field sites would have more complex geometry than this. Major goals are to NEVER run over the cord, prevent damage from objects to the cord, and how to cover the field space (the pattern) to function in a safe and efficient manner.

Was wondering what anyone might have as far as clever ideas, insights etc. Maybe other than OMG! Do Not Do This! Joking -- if you do see cause for OMG-Do-Not-Do-This -- chime in, too.

Expected Voltages will likely be US 480V 3 Phase -- with about 10 to 100 HP at the mobile equipment end. Equipment will likely have SMALL batteries on board for transit between field sites and in-and-out of the barn without a cord connection. Cords I have used on test runs are TC - Tray Cable wiring, with and without PVC coated seal-tite to prevent damage. So far, this has worked well, but if anyone has other and/or hopefully better suggestions on cord, that is welcome, as well.

Thanks!

 

[MossRoad]

Dragging it will cause wear and the possibility of snags, whereas the real method avoids friction, dragging and snags. It just lays the cord down and picks the cord up. No wear, no tear, no kinks.

 

[herm0016]

what if you did an overhead cable system like the camera at an NFL game that hovers over the field. if the 2 cables are isolated, they could be the conductors. reels on each corner with some kind of automated tracking pull the diagonal's to the correct position over the tractor / implement. one post on each corner of a field. high voltage to keep the current down. maybe 480 single phase. i bet we could design and build a system that can support a 1/4 section. and what if we could build it strong enough to hold some implements over the field, like automatic weeding, works with machine vision and identifies the plant grabs and pulls out the ones you don't want.... there is already an app that will do it on your iphone. dragging would not work when the crops are up and you need to do anything. the reel/drop eliminates this issue as well.


another idea, attach to the side of the pivot, pivot follows machine around with the power cord hanging from it. this seems like it would really be quite easy to implement. like the pendent on a bridge crane, it slides down the rails on the pivot. the cable has good strain relief and you attach a strain gauge to this, when the strain gauge senses some set amount of force, the pivot follows. the "tractor" pulls it along like a dog walking a human.

 

[Phil Timmons]

Dragging it will cause wear and the possibility of snags, whereas the real method avoids friction, dragging and snags. It just lays the cord down and picks the cord up. No wear, no tear, no kinks.

understood and agreed. What we are seeing on the (much) shorter cable tests 100 to 200 feet -- the cable does not have much issues with snags or wear, but we do have put some planning in the route to not cross the cord. Maybe think of this like a vacuum cleaner in a REALLY big theater or auditorium? With a 200 foot extension cord.

 

[Phil Timmons]

what if you did an overhead cable system like the camera at an NFL game that hovers over the field. if the 2 cables are isolated, they could be the conductors. reels on each corner with some kind of automated tracking pull the diagonal's to the correct position over the tractor / implement. one post on each corner of a field. high voltage to keep the current down. maybe 480 single phase. i bet we could design and build a system that can support a 1/4 section. and what if we could build it strong enough to hold some implements over the field, like automatic weeding, works with machine vision and identifies the plant grabs and pulls out the ones you don't want.... there is already an app that will do it on your iphone. dragging would not work when the crops are up and you need to do anything. the reel/drop eliminates this issue as well.


another idea, attach to the side of the pivot, pivot follows machine around with the power cord hanging from it. this seems like it would really be quite easy to implement. like the pendent on a bridge crane, it slides down the rails on the pivot. the cable has good strain relief and you attach a strain gauge to this, when the strain gauge senses some set amount of force, the pivot follows. the "tractor" pulls it along like a dog walking a human.

Good ideas -- on the first -- overhead, or at least partial overhead is a good idea. Have even pondered "floating" (lift balloons) for some of it. Agree on the high(er) voltages making the long runs practical. By keeping voltages down to 480V, we can reliably use Ground Fault Detection on the cord and equipment, along with using common industrial surplus equipment and materials.

You might have noticed that JD is using 2400V. For our designs, we are trying to keep a limit of 600V, (what we -- Power Folks -- strangely call "Low Voltage"). 2400V gets into "Medium Voltage" and takes more specialized (expensive) components, along with creating "step potentials" (dangerous voltage gradient across the ground) anywhere something did create a fault condition.

And yeah, the overall system is intended for everything -- Weed, Plow/Rototiller, Plant, Harvest. And yeah, the Pivot method was much easier, but this aspect -- Cords -- are for areas where we not looking at using Pivot systems. Here is the backgrounder that got this started -- goes into pivots, equipment, and methods >>> VIII.3. The Electric Farm Pt. 3 – Exchange with Phil Timmons

 

[MossRoad]

That's a 13 year old discussion. Technology has advanced. GPS is extremely accurate. The reel system VS a pivot or overhead wire system seems much simpler to control, less moving parts, no or less wear items on cables, etc.

We can't drag cables from a center pivot in row crops.

One more thing about overhear wiring systems. Crop dusting.

 

[MossRoad]

With an overhead system, you'd need the additional costs of 4 towers, 1 at each field corner, 4 motor/winches for the overhead device, 4 cables that are long enough to span the entire field each, those cables would have to be strong enough to support wire that is heavy enough to provide the voltage to the tractor, and a 5th motor/winch to reel up the voltage cable. You'd also need electrical connections to each corner of the field. Then you'd need all of the controllers to operate all of it. And you'd need it at each field.

Whereas you'd only need 1 electrical connection at each field, 1 motor/winch on the tractor, and 1 electric cable if you did it the way in the original video.

Simpler is better, in this case.

 

[Thunder chicken]

I wonder how much heat is generated in a KM long spool of wire with that much juice flowing through it? Wouldn’t it become a huge electromagnet?

Forget the cord, go microwave

Wireless power transfer - Wikipedia

en.m.wikipedia.org

 

[Redlands Okie]

So microwave at the corn fields? Talk about fresh popcorn

 

[mwemaxxowner]

This is COOL stuff!