Potential and limitations for fast rotating electrical drives for mobile machines



High-speed electric drives for the traction drive on an agricultural tractor and the belt drive on a road milling machine were successfully developed and tested as part of this project. It is evident that variable single-wheel drives are possible despite the required high spread. With comparable power density, they enable an increase in efficiency by up to 20 percent as opposed to hydraulic-mechanical drives.



Statutory emission targets and rising fuel prices are driving the development of new drive concepts to increase efficiency in construction and agricultural machinery. Electric drives demonstrate efficiency advantages over the hydrostatic drives previously widespread in mobile work machines, yet they only have low power density. Concepts from the automotive industry indicate that a speed increase can significantly increase the power density in electric machines.

Research objectives

The objective of the TEAM partial project was to realize the potential of electric high-speed drives for mobile work machines and to verify the suitability of these drives based on test bed and field trials.

  • Development and construction of a high-speed gear stage for the traction drive on an agricultural tractor and for the belt drive on a road milling machine
  • Functional verification of the mechanical and electrical components at speeds up to 20,000 rpm
  • Testing of the entire drive unit on the test bed and in the field
  • Determination of system efficiency and comparison with conventional drives

Research and project partners

  • Institute for Electrical Machines, RWTH Aachen University
  • AGCO GmbH
  • Bosch Rexroth AG
  • Heinzmann GmbH & Co. KG
  • Liebherr-Components Biberach GmbH
  • Schaeffler Technologies AG & Co. KG
  • Wirtgen GmbH
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Promoted by

The German Federal Ministry for Education and Research

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Project sponsor

Project Management Agency Karlsruhe