If the hybrid technology inside John Deere's new 644K and 944K wheel loaders appears strikingly similar to LeTourneau's massive L-1350 loader, it's not just because they run on diesel-electric power.
According to officials I recently spoke with at Moline, Ill.-based Deere & Co., its new hybrid loaders, shown at this year's Conexpo exhibition, use electric generators and motors sourced from St. Louis-based Nidec Motor Corp., which purchased Emerson Electric's motor and controls division last year. The 944K is shown above moments after Deere unveiled it at Conexpo.
Nidec's unit SR Drives Ltd., based in the U.K., also supplies electric motors to LeTourneau, which builds them under license. Shown below is the LeTourneau L-1350 next to a pickup truck. Its largest machine, L-2350, cranks out 2,300 horsepower and can carry 53 cubic yards of material in its front bucket.
By comparison, Deere's 944K runs at about 500 hp and hauls up to 9 cu yd. Even so, when it goes into production in 2013 the 944K will be Deere's largest loader yet.
Certainly on different scales, the hybrid construction and mining loaders still rely on the same special motor technology, called switched reluctance (SR), that has been in development for more than 30 years. New motor controls are allowing suppliers to build SR components more efficiently and renewing interest in this method.
Manufacturers of agricultural, construction, on-road truck and bus vehicles are all actively researching hybrid platforms, many using SR, Scott Nieberle, Nidec's vice president of business development, told me today.
"We view SR technology as a key growth area for our company," he said, adding that the company is so busy it has to pick and choose the projects it thinks have the most potential. "There are more opportunities than we can handle."
Though Nieberle would not comment on Deere's loaders, citing confidentiality with his client, he did speak about why so many OEMs are looking to use SR for their hybrid vehicles.
Many hybrid vehicles on the road today use permanent-magnet motors, a tried-and-tested technology for electric motors of most all sizes. However, SR is attracting interest in part due to the increasing cost of rare-earth metals coupled with better control algorithms.
SR does not employ permanent magnets but relies on precise electromagnetic controls to obtain motion, so it is seen as a more efficient method of transmitting electric energy into mechanical energy, and vice versa.
Put more bluntly. "China is trying to control the supply of high-energy magnets, and they are doing a very good job of that," Nieberle said, adding that over the next few years, SR is poised to surge at a combined annual growth rate of 30%.
One of the benefits of going hybrid beyond the obvious—improving fuel economy, downsizing the internal-combustion engine, reducing emissions—is reduced wear and tear, especially with an off-road machine.
Hybrids reduce tire wear, for example, by sending power only to the wheels that need traction. What's more, fewer hydraulic fluids are needed as more parts go electric. The hybrid electric drivetrain also eliminates the need for a conventional transmission, making it easier for novice operators to get up to speed.
In the last century, LeTourneau's namesake espoused the benefits of electric power for most heavy machines. This century, his dream is coming true.
We'll have an in-depth review of Deere's hybrid loaders in an upcoming issue of ENR. Stay tuned.
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