Motor Insulation Material Development for Improved Power Density Navy SBIR FY2006.2 Sol No.: Navy SBIR FY2006.2 Topic No.: N06-142 Topic Title: Motor Insulation Material Development for Improved Power Density Proposal No.: N062-142-0728 Firm: SatCon Applied Technology, Inc. 27 Drydock Avenue Boston, Massachusetts 02210 Contact: Gerald Foshage Phone: (617) 897-2439 Web Site: www.satcon.com Abstract: Insulation systems for large, Brushless DC propulsion motors typically use Pulse Width Modulated (PWM) power converters with high frequency (>10KHz), high voltage switching for efficiency and control benefits but this places significant demands on the insulation system. Switching frequency, peak voltage amplitude and voltage rate of change (dv/dt) are key factors in the degradation of insulation life due to voltage stress, partial discharge, corona and other effects. Motor winding current losses affect insulation temperature and life as well. Motor wire, wire insulation, slot liner, inter phase separator and varnish form an insulation system that requires a balancing of many conflicting factors to successfully meet each applications unique requirements. For high power density machines thermal, and mechanical factors dictate thin insulation, counter to electrical and manufacturing desires for thick, robust insulation. SatCon proposes a spiral development effort, starting with this Phase I program which focus on the commercial application of improved insulation for large, PWM, PM machines. Activities include the identification of application requirements, selection of appropriate insulation system components, material testing, machine design; drive integration, system performance analysis, generation of accelerated life test procedures and equipment identification. Subsequent phases will address full scale laboratory model testing. Benefits: Packing factor and heat transfer out of motor windings limit power density in motors. To improve density it is desirable to minimize thermal resistance and thickness of the insulation system. However, with the increased electrical stresses associated with high voltage, high frequency PWM drives thicker material is needed. Even when good engineering practice is exercised to prevent added voltage stresses from high frequency standing waves due long lead lengths, and elimination of voltage concentrations with smooth arcs in place of sharp corners, PWM drives present significant challenges for existing insulation systems. Partial discharge, due to voids in insulation materials and external corona induce UV damage, thermal damage and chemistry changes. Elevated operating temperatures also lead to rapid deterioration of insulation materials. Recent additions of nanoparticles to insulation systems have shown life 5 to 10 times improvements in life. This points to a market opportunity for improved motor insulation systems with 25+ years of life. One such application that would benefit from such a product is shipboard propulsion motors. Recent experience with the Permanent Magnet Motor (PMM) development by another vendor for the DD(X) found that the proper insulation system was a major factor in an initial PMM motor failure. A potential 300 ton savings could have been realized with the successful implementation of PMM for the DD(X), save for the insulation system limitations and risks. Return