As part of the company’s continued research into the electrification of agricultural machinery, John Deere’s latest venture has seen it develop an electric cable-powered tractor producing up to 400hp.
The electrically-powered tractor is part of a wider research project, GridCon, a joint initiative by John Deere and the University of Kaiserslautern and Baum Consult, is exploring potential avenues for farms to supply and use their own energy.
It comes on the back of Deere’s recent foray into a fully electric tractor, which consisted of the SESAM (Sustainable Energy Supply for Agricultural Machinery) tractor presented in 2016. However, the GridCon tractor looks very different to its predecessor, as it features no cab and no rows of batteries underneath the bonnet.
According to Deere, it is the first vehicle to be fully electric, permanently cable-powered and capable of fully autonomous operation in the field.
Based on a John Deere 6210R tractor, GridCon uses a cable connection from the field border to the machine, which transfers power continuously at over 300kW. A 100kW electric motor powers the tractor’s continuously variable transmission, and there is an additional 200kW outlet to power implements.
A drum fixed to the tractor carries up to 1,000m of cable, although the length can be extended if required. In the field, the cable is fed out and reeled in while guided by a robot arm to keep the operation friction free and at low load. A guidance system is also used to prevent the tractor running into or over the cable.
At work, the tractor autonomously follows pre-set rows at operating speeds of just over 20kph. The vehicle can also be guided manually using a remote control, said to be useful when maneuvering the tractor to start work on field borders, for example.
A power supply of 2.5kV AC is required, and the GridCon tractor uses 700V DC for electric power distribution, both on-board and for implements. The machine employs a cooling infrastructure for off-board electrical use, while total efficiency of the drivetrain is in the region of 85 per cent, claims the manufacturer.
Total empty weight of the working prototype GridCon tractor including cable drum and robot arm is about 8.5 tonnes, about the same weight as a conventional John Deere 6195R tractor but with twice as much power. Research engineers are aiming to reduce the weight further by at least one tonne.
Besides this favourable power to weight ratio, Deere says the concept offers the twin benefits of noiseless and emission-free operation. Compared to battery-powered tractors, the GridCon tractor also delivers about 50 per cent lower machine and operating costs, says the manufacturer.