Buying File Gallery: 30- to 40-Ton Excavators

The new Computer Aided Power Optimization system in the Robex 7 Series excavators traded the 3 Series' four work modes for three modes—Heavy Duty, General and Breaker—and added the choice of either High Power or Standard Power. Being able to customize the power in each mode allows the operator to match engine speed, pump speed and system pressure to the application at hand. A self-diagnostic display was added, which continually monitors 48 machine functions and facilitates detailed diagnostics with a laptop.

Number of 30- to 40-ton models: 3

New models: R290LC-7, R320LC-7, and R360LC-7

Product-line features: Two spools were added to the Robex 7 hydraulic system. Now with nine spools, Hyundai says hydraulics respond faster with more power. Refined joysticks contribute to what the company claims is about a 15-percent increase in operator efficiency. Cummins engines power these three excavators.

First All-Volvo Excavators

The president of Volvo's excavator business unit, Eric Nielson, refers to the B Series excavators introduced in 2002 as the "first 100-percent Volvo excavators," even while admitting that some very effective features of the purchased Samsung line have been retained. Volvo created the six-cylinder engines used in its EC290B and EC330B specially for the B Series. The turbocharged and intercooled diesels are carefully matched to the hydraulic system, and the electronic controller's Advanced Mode Control automatically senses joystick movement and system pressure to adjust work modes. Standard equipment on the EC290B is an in-cab control for switching between one- and two-pump flow for hammer-to-shear exchanges.

Number of 30- to 40-ton models: 2

Product-line features: The Contronics controller records error codes and status indicators to simplify troubleshooting. Volvo opted for an aluminum hydraulic-oil cooler to maximize heat dissipation and minimize corrosive damage. 

Redesign Beefs Up the Line

The CX330 comes with 19 percent more horsepower than the 9050B it replaced, and new pumps in the open-center hydraulic system produce nearly 8 percent higher pressure and 6 percent more flow. The standard CX330 outweighs the 9050B by about 4,500 pounds and develops nearly 15 percent more arm-digging force, and 16 percent greater drawbar pull. Construction Equipment's Field Test confirmed that the CX330 swings 7.6 percent faster with a loaded bucket, and will lift 13.6 percent more over the idlers than the 9050B.

Number of 30- to 40-ton models: 2

New models: CX290 and CX330

Product-line features: The Pro Control System coordinates hydraulic and engine power, offering three working modes compared to the B-Series' four modes. The Automatic mode analyzes loads and operator input at the joysticks so the computer can adjust the engine and hydraulics. Power boost automatically increases main pressure 10 percent for 8 seconds in tough digging. Case excavators are developed through its Sumitomo joint venture in Japan. Case supplies the Chiba factory with Case engines and cooling-system components.

Controller Simplifies Operator Choices

The HIOS II hydraulic system in Hitachi's Zaxis 270LC and Zaxis 330LC excavators has an Auto Power Lift, which temporarily increases hydraulic power by 6 and 9 percent, respectively, during heavy lifting and bucket-filling operations. Two work modes (digging and attachment modes) simplify operations.

Number of 30- to 40-ton models: 2

Product-line features: Hitachi's on-board data logger, the Machine Information Center, captures and stores machine performance data such as engine speeds, hydraulic temperatures, pump pressures, alarms and faults, hours of operation and more. Data can be downloaded through an mSeries Palm Pilot and transferred to a personal computer. Hitachi's PC software generates reports and graphs highlighting utilization, performance history, and other details that can supply information to improve operator training, machine maintenance, and replacement decisions. Hitachi's excavators are most easily distinguished from their John Deere counterparts by their use of Isuzu engines.

Controller Keeps Engine Power Constant

JCB's Advanced Management System senses the load on the hydraulic system and matches engine output and hydraulic demand, maintaining constant engine effort for efficient operation. Flow on demand means hydraulic speed and power output is proportional to lever movement. Power Boost automatically provides a temporary 10-percent increase in breakout force when digging becomes difficult. Performance and diagnostic information recorded by the management system can be analyzed to improve machine usage and reduce downtime.

Number of 30- to 40-ton models: 1

Product-line features: The Plexus filtration system extends hydraulic-filter change intervals to 1,000 hours and hydraulic-oil change intervals to 5,000 hours. Twin engine-oil filters stretch oil and filter changes for the Isuzu engine to 500 hours. 

Computer Creates Predictability

The Powerwize II electronic system on the 270C LC and 330C LC replaces three power modes with one choice—Work or Attachment mode. The computer automatically adjusts swing, boom, and stick priority based on working conditions, and will