Evolution of ac-drive technology

The introduction of inverter drives has stimulated development of the ultra-class haul trucks in operation today.

For OEMs not possessing the luxury of in-house engineering facilities dedicated to component and system design, efficient product evolution and time-to-release is reliant upon outsourced technology and subcomponent development. Historically, suppliers have offered similar products to competing groups of OEMs. Unfortunately this practice can be detrimental, suppressing competitive spirit and innovation. But when that fortunate day finally arrives and a truly significant technological breakthrough is realized, product introduction can be dramatic, affecting customer preference and ultimately changing the face of the industry. This scenario is well supported when considering changes accruing within the haul-truck industry.

Caterpillar, while being a dominating player in the industry and holding around 50% of the global haul-truck market, continues at least for now to develop and manufacture an extensive, well-proven, but purely mechanical equipment line. LeTourneau took over the rights from General Motors of Canada in 1985 to build haul trucks and was renamed Marathon LeTourneau. The new company's haul trucks incorporated a unique dc-based drive system, but haul-truck production stopped late in 1990 so the company could concentrate on developing its line of large-capacity, diesel-electric wheel loaders.