Electric tractors - a step forward in energy self-sufficiency on the farm
Monday, April 6, 2015
Uprated onboard generators and transportable 100 kW batteries are plowing more voltage power into cultivations in Europe
by NORMAN DUNN
Cutting fossil fuel inputs through more efficient energy application is just one advantage of more electrical power outlets on tractors. For the operator out on the field, the real joy is the simple plug 'n play aspect. Goodbye, at least partially, to dirty and awkward hydraulic hose coupling or struggling with the pto drive shafts. A lot less operational noise, too, in many cases.
So it's not too surprising that there's a gradual shift to more electrical power in this field. Of course, we already have a full-blooded diesel-electric tractor from Rigitrac in Switzerland with its EWD 120 model. Here, a 126 h.p. Deutz engine powers a generator driving four 44 h.p. hub electric motors, one for each wheel. This permits hydro-pneumatic individual wheel suspension as well as active slip-control per wheel.
Result: a revolutionary tractor with four-wheel steering, adjustable ground clearance and a top speed of 65 kilometres an hour. Direct drive to each wheel means power transfer efficiency is rated at 85 per cent for the Swiss machine. Even direct hydrostatic drive only achieves around 65 per cent in this respect.
Most of the bigger players in the farm equipment sector now offer electrical power on tractors from onboard generators – for instance Deere, Same Deutz-Fahr, Belarus and, most recently, a prototype Fendt. There's now a stream of implements with electric motors that can be simply plugged into such power sources – fertilizer spreaders, sprayers, trailers and the like. Modern pto-driven generators for extra E-power include the GKN Walterscheid model that can produce up to 136 h.p. at 900 rpm.
Deere was one of the early arrivals in this growing sector with its so-called E-tractors on offer for over five years now with the current 6RE range offering an output of 480 volts. This year, Fendt's new "X Concept" tractor hikes possible output up to a powerful 700 volts DC, translating into an impressive 174 h.p. wired directly to the implement drive. But we won't see this in the showrooms, says Fendt. It will only be used towards designing other models.
Even with generators already onboard, an added battery can boost electrical power potential from diesel/electric tractors. For instance, this year Deere is introducing a mobile lithium-ion battery for mounting on the front weight brackets of its 6RE tractors. Charged back in the barn and then plugged into the tractor network, this can boost output by around 130 h.p. for powering implements. The output of battery, on-board generator and diesel engine is managed in the cab via touch screen control.
This latest introduction is a very significant one. It offers the chance to use home-produced power in crop production – renewable energy from biogas-fuelled generators, from wind turbines or solar panels. Now, that's a real step forward in energy self-sufficiency on the farm. BF