Method and apparatus for reducing hot spot temperatures on stacked field windings

Abstract

A method and apparatus for a generator coil includes a plurality of stacked windings in a rotor where individual turns are stacked in parallel sided radial slots in the rotor. Each successive turn has the same width substantially corresponding to a constant width of each slot, wherein a first turn has a first thickness and a second turn has a second thickness thicker than said first thickness. The second turn is employed in regions of high temperature thereby reducing the temperature thereof.

1 . A method to reduce field winding temperatures for windings in a rotor, the method comprising: 
 varying turn thickness of individual turns with at least two different thickness turns stacked in a parallel sided slot of the rotor;    employing thicker individual turns in a region corresponding to a field hot spot to reduce resistance and local heat generation thereof.    
   
   
       2 . The method of  claim 1 , wherein said each individual turn comprises an axial length of copper having a generally rectangular cross-sectional shape.  
   
   
       3 . The method of  claim 1 , wherein a net turn thickness and number of turns are identical to that if a constant turn thickness is employed in slots of identical geometry.  
   
   
       4 . The method of  claim 1 , wherein layers of turn insulation disposed between said individual turns have substantially the same thickness.  
   
   
       5 . The method of  claim 1  further comprising: 
 employing thinner individual turns than said thicker individual turns in a region corresponding to a non-critical region.