The purpose of the use of Kondorfer

 This is method to start a motor using an autotransformer.
   As an autotransformer acts as a reactor if neutral point is open without separating an autotransformer after starting, a motor starts while rated voltage is induced when a tap is short-circuited.
   The feature of this method is that shock is reduced as power and a motor are not separated when a tap is changed into a direct line. Therefore this is commonly used to start a large capacity motor with high starting torque and GD2 value of load. 
  
ㆍ Calculation of capacity of a Kondorfer 
 
  
ㆍ Starting method of a Kondorfer