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Direct Drive Modular Permanent Magnet Arc Generator


Invention Reference Number

Small wind turbine and building

Wind or hydro power are predominantly large-scale with giant generators to convert wind or water captured by turbines into electricity. But residential-sized wind turbines could generate power for a whole house. This technology is an electrical generator to directly extract the rotational motion from a low-speed wind or hydro power machine. The generator eliminates the need for gearboxes and additional stages of power conversion, reducing system weight, volume, loss and cost. 


A module consisting of a direct drive magnet array can be mounted on a rotating turbine of a low-speed wind or hydro turbine machine. This induces voltage in a stationary module that consists of coils and cores that spans less than a 360-degree arc. The number of modules can be increased depending on the desired power output. This direct drive permanent magnet modular arc generator can be sized so that output can be increased, as each module is electrically independent of the others. This improves efficiency of the machine because power can be taken only form a few of the modules when less power is required or available from the turbine. As the rotor magnets are directly connected to the rotating turbine, the need for a gearbox is eliminated and the system efficiency improves. Gearbox maintenance issues are eliminated and system reliability improves. The system cost can be reduced by replacing the magnet array by a toothed rotor and moving all active sources i.e. coils and permanent magnets on to the stationary module.   


  • Eliminates need for gears, gearbox 
  • Eliminates gearbox maintenance 
  • Modular construction so output can be increased as needed 
  • Can add magnetic coils as needed 
  • Reduces complexity and can be less expensive 
  • Greater efficiency 
  • Fault tolerant, as other modules available if one fails 
  • Reduced short-circuit possibility 
  • Improved reliability 

Applications and Industries

  • Energy 
  • Wind and hydro turbine manufacturers 
  • Residential low-power wind and hydro industries 


To learn more about this technology, email or call 865-574-1051.