  
 example 4 12   

 (a)
 total current 433.01 -286jA 
 overall power factor 0.834 lagging 
 copper losses in synchrounous motor 6250W 
 copper losses in cable 24.25KW
 (b)
 total current 433.01 -178jA 
 overall power factor 0.925 lagging 
 copper losses in synchrounous motor 6250W 
 copper losses in cable 19.73KW
 (c)
 total current 433.01 -94jA 
 overall power factor 0.977 lagging 
 copper losses in synchrounous motor 6250W 
 copper losses in cable 17.67KW 
 (d)   
copper loss of synchronous motor this is evidently minimum when tand=0 cosd=1 