Target technology development for a small handheld powertool motor with outstanding power density

Small two-stroke gasoline engines are the major power source for professional outdoor power equipment such as hedge trimmers, chain saws, blowers and cut-off saws. However, electric motors energized with Lithium-Ion-based batteries as a power source strongly catch up. For some time now, small non-professional equipment with a battery-based power source is available. But only since 2010 professional grade cordless mobile power chain saws are available. The effective cutting performance of the top products still seemed to be limited to the equivalent of the smallest gasoline chain saws. With enhanced motor performance and strict target technology development it is now for the first time possible to launch professional battery chain saws with further increased output power. To achieve this optimization in performance but also in terms of production stability and cost it was necessary to investigate both the requirements of the classic product development and the production process together. This article focuses on an outer rotor EC-motor. Ways for enhancing energy efficiency and their influence on the production process are derived. An approach for optimizing production in terms of cost-effectiveness and stable premium quality is discussed.