Caterpillar ended years of rumour and speculation on March 30 when it announced to mining press and analysts that it is embarked on its biggest mining truck development programme, in which it is investing a record amount. Ed McCord, Cat’s Product Manager for Large Mining Trucks and Shovels, explained that more than half the world’s mining trucks are Cat machines, and therefore more than half the world’s mining trucks are mechanical drive. However, the new programme includes electric drive and will ensure there is a “Cat truck for every application.” McCord also said this development would result in a “quantum leap in electric drive support.”
McCord explained in detail how other truck makers’ electric drive systems employ components bought in from various suppliers, engines, wheel motors, software and other essentials of the electric drive system. Caterpillar’s system is to be a fully integrated system. Which he says will bring productivity and reliability benefits. So, the engine, the brand new Cat C175, the alternator, the controls and hardware, and the wheel motors will all be Caterpillar products. Mitsubishi Electric will supply the most important part, the power inverter.
Mitsubishi Electric brings excellent credentials to this alliance, being the world’s largest supplier of Insulated Gate Bipolar Transistors (IGBTs), the core element of the AC drive system. The company is also the leading supplier for automotive hybrid systems and has extensive experience in rail applications of AC technology.
IM was able to see the current test bed electric drive Cat truck, a modified 797. That machine has been operating at the Tinaja Hills proving grounds in Arizona since May 2005.
The truck programme that is underway will result in substantial upgrades to all mechanical drive products: 785C, 789C, 793D and 797B. Two electric drive units of over 200-t capacity will be released, but we will likely have to wait to MINExpo 2008, to find out exactly what these trucks are all about. However, IM will report more on this exciting development in its US technology feature in September this year.