Europe's Agritechnica equipment show in 2007, provided a glimpse of the future applicator at the John Deere booth. If you have paid attention to Caterpillar (CAT), you may have caught a better look when the D7E Dozer was introduced in 2009. Each of these was a peek at the future of applicators in another segment of the ag industry. Then it happened. Those who attended AgConnect in Florida this past January saw the electric drive RoGator with its diesel-powered on-board generator and electric drive wheels, a functional concept machine from AGCO Corp.

Looking at the electric-powered features and related benefits of these three machines and you can project a not too distant revolution in application equipment. Fuel, maintenance and parts costs will all be reduced, while expected use-life will be significantly extended. It will take today's on-board computer controls to another level, from monitoring drive systems to controlling them.

CAT promotes reduced training time needed for new operators. Doug Daws, director of product management, AGCO Application Equipment, concurred. "The operator will simply choose one of several operating modes, and the machine will handle operations accordingly," he said. "A few years ago, the electric drive RoGator would have been looked at as futuristic. There has been enough application of the technology by Caterpillar and others that people see it as a reality that is coming."

Today's reality includes 10 percent to 30 percent reductions in fuel use and 10 percent increased productivity with the CAT D7E.

At AgConnect, AGCO spokesmen suggested the off-the-shelf Switched Reluctance Motor Drives were 20 percent more efficient than current hydraulic wheel drives. Each of the four motors produces 36 percent more torque, which equates to 35 percent more pulling power and a 20 percent reduction in fuel. And that's without modification of other components.

John Buschena, manager, application chassis equipment, AGCO Corp., explained why the company has explored the electric drive train. "One of the big advantages for putting this technology in a field sprayer is the amount of acceleration and deceleration at row ends," he said. "With regenerative braking, you store power every time you slow down and then use it to accelerate, providing significant opportunities for performance and efficiency gains. However, other components are still hydraulic or belt driven, and there are also opportunities for efficiencies and savings in those areas."

Buschena pointed out that the RoGator itself was an off-the-shelf model. In a production diesel-electric machine, everything would be up for redesign to optimize all components and take full advantage of the new power source. The electric drive concept RoGator is currently undergoing independent, third-party testing of wheel motors, as well as defining operating efficiencies. Daws suggested the results will likely affect not only future wheel motors, but also the design of the entire machine.

"Optimized wheel motors may be half the size of the ones we are using today," he said. "In a new design, we will also be able to optimize where we put the engine and components. The fan can go anywhere. You aren't tied to how you mount various components. It allows a simpler machine design."

Embracing New Technologies

Although John Deere in the U.S. had no comment when asked about diesel-electric systems, the company has embraced the new technologies, if selectively. The 2009 annual report featured the 7030-E Premium Series (200 and 211 hp) tractors being sold in Europe. Deere has also introduced electronic-driven components in other products, including electric-powered cutting units in some of their zero-turn mowers.

In some ways, the Deere tractors are the mirror image of the electric drive RoGator. Although the Deere series doesn't have an electric drive train, most auxiliary components have been redesigned with electric motors versus hydraulic or mechanical. Another difference is the generator is integrated into the engine design as a new type of flywheel. It produces 400V (three-phase) and 230V (DC) power and more traditional 12V power.

The results are impressive based on John Deere's European product information. Simply switching components
from parasitic (engine driven) to electric power with independent control frees engine power to deal with field conditions. The tractors claim one of the highest power-to-weight ratios in their class, increased load response and improved transport acceleration on the road — as much as 15 percent faster — all while using 6 percent less fuel.

Electric-powered components, such as the coolant pump and fan motors, can vary their speeds by engine cooling needs, not engine speeds. The electric motors eliminate lags in cooling and automatically shut down when not needed for greater efficiency. As a result of improved cooling, John Deere's Intelligent Power Management (providing a boost of up to 35 hp, as well as greater torque rise) kicks in at 1,250 rpm instead of 1,700.

Multiple Uses for Electric Power

As Daws suggested about futuristic RoGators, electric drives on various components also mean the manufacturer can locate them where they make sense, not where they are needed to tie into the engine. On the 7030 E-Premium Series, the A/C compressor is located under the cab and away from engine heat. With its independent power source, it can reach maximum cooling capacity whether the tractor is idling or at full speed. The electric drive on the fan means cleaning dust and debris from the tractor grill requires only that the fan direction be reversed. 

Of course, there will always be components that simply are best suited for hydraulic powering. Here, too, electric power will play a role, independently powering a hydraulic pump and simplifying placement of remote valves. Put this kind of independent power and control on field applicators, and new design and efficiency opportunities quickly present themselves. Spray pressure and boom control, as well as the above-mentioned components, can all run at peak efficiency as needed, regardless of power demands placed on the engine and drive train.

"Once you have electric power on the machine, you can get better control," said Buschena. "With an electric motor on a pump, you can run it at the optimized level all the time, and when not used, it is off. Today's pumps are always turning and incurring wear, even when not pumping anything."

Seeing Multiple Benefits
When it comes to application, benefits are easy to recognize. When John Deere, introduced the E-Premium Series tractors in Europe, German fertilizer spreader maker Rauch introduced the Axis EDR, an all electric, twin-disc fertilizer spreader. It uses the three-phase power for two motors that drive the spreader discs, while using 12V power to drive the agitators and electric actuators. The DC motors offer infinitely variable speeds.

All components on the spreader are operated at optimum speeds without regard to tractor rpm or ground speed, maintaining spread pattern and saving fuel. Separate controls allow calibration without the spinners operating. Spinner disks can reach full speed before being put under load. They also shut down quickly with electric motor braking. Connecting or disconnecting the system is as easy as pulling a plug.

Simplicity permeates diesel-electric systems. Electric systems require laying a cable to a motor. There are no hoses and connectors, much fewer leaks to worry about. There are no belts and pulleys or chains and sprockets to replace, just a motor that delivers speed and torque as needed. Of course that means fewer parts and less maintenance to budget for. Caterpillar reported its D7E electric drive train has 60 percent fewer moving parts.

Combine that reduction in drive train parts with elimination of parts from other components, and the impact becomes staggering. As an example, a few years ago John Deere introduced the 2500E, a diesel-electric "hybrid," commercial style, zero-turn mower. A belt-driven alternator powered an electric mower drive, replacing the original hydraulic powered drive. According to company literature, making that one change eliminated 102 potential leak points. Imagine the number of leak points eliminated in a RoGator or a John Deere 4630 self-propelled sprayer.

If increased fuel and operating efficiencies and reduced parts and service weren’t enough, another driving force toward electronic systems is working life. Caterpillar claims the major components on its D7E will have 50 percent longer life than conventional drives. In addition, the company is designing all major components to be rebuilt for a second full life, further extending the machine’s projected use.

Impact on Profits

Although such reductions in parts and extended life may negatively impact company profits, Daws suggested that shouldn't hinder adoption of the technology. "We try to provide value to our customers," said Daws. "The question has always been how do you get a machine to last longer and still be affordable. We always knew we could build a 20,000-hour machine, but no one could afford it. This new technology is affordable."

Daws said AGCO has numerous projects in addition to the electric drive RoGator that are looking at drive train technologies. "There are not a lot of advances likely with current drive trains," he said. "The big advances down the road will come with alternative drive methods, whether electric or something else."