Caterpillar has introduced the D7E (Circle 924)—the first electric drive track-type tractor using modern technology. The revolutionary electric drive system developed for track-type tractors gives the D7E an optimum balance of power, efficiency, control and maneuverability. The system delivers higher productivity, reduced fuel consumption, reduced operating costs and longer drive train component life compared to other tractors in its size class.
The D7E is in the 60,000-lb weight range and is powered by a Cat C9 engine producing 235 hp. Compared to the Caterpillar D7R Series II, the D7E will deliver 25% more material moved per gal of fuel, 10% greater productivity and 10% lower lifetime operating costs.
In the D7E power train, the diesel engine drives a generator to produce electricity that ultimately powers two AC electric drive motors, which are connected to a differential steering system. A traditional mechanical transmission is not needed, because the variable speed electric motors serve the function of a continuously variable transmission. The electric drive train has 60% fewer moving parts compared to previous D7s. The electric system also provides power to auxiliary components so that no engine belts are needed.
Caterpillar plans to commercially introduce the D7E in select markets during 2009.