Euclid-Hitachi specified a final-drive system from Fairfield Manufacturing for its R280 AC haul truck. Testing on the geartrain components included performance and lab testing, square-and-spin tests, and torque-spike testing.

Using the Siemens SIEBAS ac controller and high-speed, low-weight ac motors coupled with a Euclid-Hitachi designed rear axle created a machine that can perform with the best haulers in its class. It is also said to offer one of the lowest costs-per-ton (of haulage) in the industry, with components that were designed and tested for years of operation with minimal service.

Initial geartrain development began in June 1996. Euclid-Hitachi researched multiple final-drive designs, from double-reduction to double-reduction and -path epicyclic geartrains. Each design was analyzed for its efficiency, durability, and cost. To help with the details of the drive, Euclid-Hitachi approached Fairfield Manufacturing.

Euclid-Hitachi, Siemens, and Fairfield Manufacturing Co., Inc. cooperated throughout the design process. Using a double-path planetary final-drive system, the R280 AC is said to have a high "power-to-cost" ratio. By using the experience of its engineering and sales teams, Fairfield helped make final design improvements, which included tooth-profile modifications for noise reduction, and misalignment and cost reductions in the manufacturing of the final product.

Jim Dammon, VP of Engineering for Fairfield Manufacturing stated, "The manufacturing and engineering capabilities that Fairfield possesses allowed us to work closely with Robert Ciszak, Euclid-Hitachi's Senior Design Engineer involved with the R280 AC drivetrain. We were able to ensure that the gearing supplied by Fairfield was capable of meeting this monstrous truck's performance needs. As the R280 AC is used in extreme load conditions and demands rugged performance, using anything less than top-quality gearing would not fit this specific application." After the initial planning phase was complete, Fairfield's engineering department and Euclid-Hitachi cooperated closely to enhance the design of the gears and reduce tooling cost by researching materials and production methods.

According to Ciszak, "Euclid has depended on the experience and excellence of the entire staff at Fairfield for over 35 years. From the initial prototype to production, they have always provided us with consistent, high quality components our customers can count on."

R280 AC dimensions.

At the beginning of 1998, Fairfield Manufacturing received the final prints from Euclid-Hitachi and compressed its lead times for prototype orders. The enhancement of gearing attributes continued throughout the manufacturing of the prototype orders. This process eased gear manufacturing for the production orders that followed and reduced gearing costs. The design-cycle compression allowed the creation of the R280 AC prototype to commence in April 1998.

Eric Rodarmel, Sales Manager overseeing the Fairfield components in this project, stated, "This has been an exciting and fast-paced project. The initial and continued support of Fairfield's Engineering, Planning, Materials, and Production Departments, and the support Fairfield received from Euclid-Hitachi (specifically from Eugene Skutt, Lynn Smith, and Robert Ciszak), has certainly made this project a success for both companies. This project exemplifies the capabilities of the entire Fairfield organization."

By October 1998, the first R280 AC prototype machine was operating at Lehigh Coal and Navigation in Tamaqua, PA. Euclid-Hitachi conducted an extensive test program that included performance testing, lab testing, and four square-and-spin tests for final drive durability and efficiency. It completed the evaluation of the geartrain with torque-spike testing.

R280 AC Specifications

Engine

• Cummins QSK60-L or Detroit Diesel 16V4000 • 2013 kW (2700 hp)

Electric drive system

• Siemens motors and advanced ac control system • Wheel motors • 3430 kW (4600 hp) continuous driving (minimum)/trolley applications • 4474 kW (6000 hp) continuous electrical retarding (to stop) • High-speed/high-efficiency design with 3450-rpm top motor speed

Final drive system

• Euclid design • 35.816:1 standard or 40.789:1 optional gear ratio (all Fairfield components) • Top speed with Michelin 50/80R57 tires: 62 km/h (39 mph) standard; 54 km/h (34 mph) optional • Loaded gradability: 30% standard; 35% optional • Maximum tractive effort: (295,000 lb) standard; (336,000 lb) optional

Tires

• Michelin 50/80R57 • Rim diameter 57 in • Outside diameter 3.6 m (12 ft)

Brakes

• Front Three-head dry disc (per wheel) • Rear Multiple-plate, oil-cooled wet disc • Park Two-head (per assembly) dry-disc spring apply (hydraulic release)

Mass

• Empty 147,100 kg (396,200 lb) • Loaded 435,500 kg (960,000 lb)

Torque-spike testing measures the effects of inverter failure on geartrain components. During a failure, it is possible to generate surges as high as 1200 A at 3000 V. Empirical models were used to predict results—initially to determine the frequency of the fault. Then the axle shaft was designed to resonate at a frequency different from the harmonics of the fault frequency. The system was spiked 36 times with accelerometers and strain gauges mounted on the axle shaft with a specially designed wheel-mounted computer for data storage. Results showed that 45,000 N•m (33,200 lb•ft) torque was produced during the spikes at each axle shaft. Tires were spun backward on a fully loaded 435,500-kg (960,000-lb) vehicle. After testing, the geartrain was inspected and no damage was found. The axleshaft effectively protected the geartrain without failing.

By October 1999, Euclid-Hitachi finalized its new product release by presenting the Engineering Integrity Society with a technical paper entitled Dynamic Simulation and Instrumentation of a Four Mega Watt Transmission of a New 280 Ton Vehicle. Euclid-Hitachi has since delivered its first production unit to Iscor Mining at Grootegeluk Coal Mine, South Africa.