2 min read / April 24, 2018 / Mark Barr, Director-Longview Engineering, Komatsu
Hybrid Electric Drive, specifically SR (Switched Reluctance) technology, is generating a lot of buzz. It’s easy to see why, after all, there’s a reason why all the major players in the industry did their research and decided to focus on SR electric drive. But Komatsu’s history with the technology goes back much further than that.
Komatsu’s expertise in electric drive earthmoving equipment dates to the 1950s when R.G. LeTourneau Inc. (acquired by Komatsu) began pioneering the application of diesel-electric drive into earth moving equipment. Letourneau recognized years ago that electric drive was very applicable to large earthmoving off-highway equipment and could result in improved production, efficiency, and fuel savings.
A lot of these technologies don’t evolve, they become feasible due to innovations and forward thinking. The real trick is figuring out how to reliably apply them, especially in very demanding applications like earthmoving.
In the mid-1990s, the company began working on the Switched Reluctance technology that is incorporated into the Komatsu’s current P&H wheel loader equipment line. By the early 2000s, it had built prototypes. In 2004, we were ready to launch the technology into new model production. During 2008, the company began to transition its entire wheel loader product line to SR Technology.
One of the benefits is it is power dense. An SR motor can put out the equivalent power of a larger one in a smaller package. The rotating portion of an SR motor is lighter, which translates to less stress on the gear train, improving life cycle and duty cycle on components. Additionally, SR effectively has no speed limitations. Compared to other motors, SR has a significantly higher speed capability.
Komatsu now has more than 150 P&H surface wheel loaders using SR around the world. That means millions of hours of cumulative operation and tens of thousands of individual component operational hours.
Building on those experiences, we’ve developed advanced SR control algorithms to optimize efficiencies in applying torque to the ground, controlling wheel slip to minimize tire wear and significantly reducing fuel burn. We’ve also incorporated decades of mining duty traction motor design knowledge to ensure our motor and generator designs are rugged, reliable and up to the task of achieving long life in the tough mining environment.
SR is the future, but it’s been part of Komatsu’s for a long time. Everything we did has been built on decades of work and experience. Not only can we offer the benefits others are beginning to scratch the surface on, but we know how to apply this technology and optimize every bit of reliability, fuel efficiency and performance.