Efficient electric fan with focused air flow

Abstract

An efficient, high-volume fan producing a focused air flow comprises an electric motor having a central, segmented stator and a rotor with a set of permanent magnets and a back iron. The magnets are preferably rare-earth magnets such as neodymium magnets. The fan further features a plurality of lightweight blades, each blade comprising an airfoil cross section comprising a foam core that may be covered with a high tensile-strength skin or plastic coating. In the preferred embodiments, the high tensile-strength skin is an aluminum skin, and edges of the blades have edges are joined with a folded hem. The blades may have a windward tilt, and may be constructed so as to intentionally detach upon impact. The segmented stator, blade shape, and other aspects may be varied for different applications.

1 . A high-efficiency electric fan, comprising:
 an electric motor with a central, segmented stator, each segment including an electrical winding;   a rotor with a set of permanent magnets and a back iron;   a plurality of lightweight blades, each blade having an airfoil cross section with a foam core; and   a controller for driving the winding of the motor such that the blades produce a focused air flow.   
     
     
         2 . The high-efficiency electric fan of  claim 1 , wherein the blades are covered with a high tensile-strength aluminum skin with lengthwise edges joined with a folded hem. 
     
     
         3 . The high-efficiency electric fan of  claim 1 , wherein the blades are all-foam or covered or coated with a thin plastic skin. 
     
     
         4 . The high-efficiency electric fan of  claim 1 , wherein the magnets and back iron are encapsulated in plastic or other protective material. 
     
     
         5 . The high-efficiency electric fan of  claim 1 , wherein the blades have a windward tilt. 
     
     
         6 . The high-efficiency electric fan of  claim 1 , wherein the blades intentionally detach upon impact. 
     
     
         7 . The high-efficiency electric fan of  claim 1 , wherein the back iron includes a back iron including a ring-shaped cover. 
     
     
         8 . The high-efficiency electric fan of  claim 1 , wherein the segmented stator may be sized for different applications. 
     
     
         9 . The high-efficiency electric fan of  claim 1 , further including a frame mounting thru a fixed axle. 
     
     
         10 . The high-efficiency electric fan of  claim 1 , further including:
 a frame mounting thru a fixed axle; and   wherein the frame is suspended from above with a plurality of suspension bars.   
     
     
         11 . The high-efficiency electric fan of  claim 1 , further including a motion sensor to enhance safety. 
     
     
         12 . The high-efficiency electric fan of  claim 1 , wherein the magnets are rare-earth magnets. 
     
     
         13 . The high-efficiency electric fan of  claim 1 , wherein the magnets are neodymium magnets.