Hybrid electric and fuel cell automobiles are one futurist solution for reducing pollution and dependence on fossil fuels. But will farm tractors ever run on electricity instead of diesel? The official line from tractor manufacturers generally is, "We're not prepared to talk about that right now."
Although the company hasn't talked about it much publicly, John Deere does have an electric motor program in the works with alternative energy technologies developer UQM Technologies. UQM recently announced that it has achieved a revolutionary breakthrough in the performance of an electric motor that could power large farm equipment.
The new development is a permanent magnet electric motor system that achieves a 10-to-1 top speed to base speed ratio, or what is commonly referred to in the industry as constant power speed ratio (CPSR). This provides both high torque and high-speed capability in the same machine at levels greater than twice that of the electric motor industry's best-performing motor technology.
Commenting on the new system, Bernard B. Poore, manager of product technology for John Deere, says, "The majority of our vehicles require low-speed torque coupled with high-speed transport and present a particularly tough challenge for electric propulsion systems. We have been working with UQM for many years because their superior technology is well suited to the variety of demanding applications in our industry. Their achievement of 10 to 1 is a significant breakthrough and will greatly improve the performance of electric and hybrid propulsion systems. We know of no other demonstrated technology that comes close to this performance."
Deere's Barry Nelson cautions that the mighty diesel won't disappear anytime soon. "Electric motor technology is an exciting breakthrough, but keep in mind that it is an advanced engineering project that might not result in a marketable product for 10 years," he says. "We have to keep looking forward, though, and electric motor technology offers the prospect of greater fuel efficiency and reduced emissions.
"Electric motors have other advantages too. They are quieter and have the potential to produce more torque than internal combustion engines."
One possible application of electric motors on tractors might be a hybrid diesel tractor that uses individual electric motors for front-wheel assist. Conceivably, a tractor could have separately controlled electric motors on each wheel, increasing maneuverability and saving weight by eliminating the need for steering linkages and transmissions.