Cat goes electric; Caterpillar expands mine haul truck range to include ac electric drive developed with Mitsubishi Electric; two 200+ ton models to be unveiled at MINExpo 2008

Diesel Progress North American Edition, May, 2006 by Dawn M. Geske

Caterpillar Inc. has announced that it will add ac electric drive mine haul trucks to its off-highway truck line through a partnership it has developed with Mitsubishi Electric Corp. While this is a departure from the mechanical drives Cat uses throughout its mining truck lineup, the ac electric drive technology is intended to complement the company's mechanical powertrain offering, adding an additional drivetrain option, which Cat said builds on its focus to produce products that are productive to its customers' bottom lines.

"This is the largest investment we've made in mining trucks in Caterpillar history and certainly demonstrates our commitment to maintaining a leadership position in the mining sector and serving the mining customer better than anyone in the industry," said Gerry Shaheen, Caterpillar group president.

To date, Cat has installed the electric drive system on its 380 ton payload 797 haul truck for testing. Cat said it anticipates initially releasing the electric drivetrain in two truck models above the 200 ton range, which it said will be unveiled at MINExpo International 2008.

Cat introduced its first electric drive truck in the 1960s with the dc-driven 779 truck, a 240 ton coal hauler. Today, its mine haul trucks are produced at its Decatur, Ill., facility where Cat said it supplies more than half of the mine haul trucks used in the global mining industry. Since introducing its 150 ton payload 785 truck in 1985, Cat said it has shipped 6000 units worldwide.

Today, Cat's lineup consists of nine 40 to 400 ton haul trucks, all with mechanical drive systems. "Caterpillar's mechanical drive trucks are the standard in the industry," said Shaheen. "Some customers, however, prefer the electric drive truck for specific applications and situations.

"Adding an electric drive to our lineup will enable Caterpillar to offer an additional solution to match customer needs."

With the ac electric drive, Cat said it is moving closer to its goal of providing a truck for every application targeting high-speed coal hauling, extreme downhill load hauling and some trolley operations.

The ac electric drive for the trucks was developed through a strategic partnership formed between Cat and Mitsubishi Electric. Mitsubishi, which has experience producing ac drives for the rail industry, will provide the power conversion for the assembly by supplying the semiconductors and other inverter components.

"This alliance combines Mitsubishi Electric Corp.'s high power semiconductor technology with Caterpillar's large mining truck design and production," said Chris Schena, vice president of Caterpillar's Motion and Power Control Division.

Cat said it will produce the alternator, planetaries, ac wheel motors, voltage regulators, controls and hardware for the drivetrain, which will make the truck "a Cat product through and through," said Ed McCord, product manager for Caterpillar Global Mining.

The trucks will also be equipped with Caterpillar's new C175 engine family (see April Diesel Progress), replacing the 3500 series engine previously used. The C175 engine comes in 64, 85 and 106 L displacements, 12-, 16- and 20-cylinders and is rated 2000 to 4000 hp for mining applications.

"We recognize that there are unique applications that would make the addition of ac electric drive an important and attractive complement to our current truck line," said Chris Curfman, president of Caterpillar's Global Mining division and Caterpillar Inc. vice president. According to Curfman, Caterpillar considered a variety of alternatives for adding electric drive mining trucks to the product offering. "In the end, it was clear that developing our own lineup is the best path to providing customers with a complete range of hauling equipment," he said.

Electric drives are just one element of the mining program that Cat is heavily investing in, as it has also announced that it will also make significant upgrades to its 785C, 789C, 793D and 797B mechanical trucks and plans to introduce a new model to the lineup between the 793D and 797B.

diesel Weblink

www.cat.com