338 



ELECTRICAL MACHINERY 



grouped to form a F-connected three-phase winding and 

 the three ends are connected to slip rings mounted on the 

 rotor shaft as shown by the left-hand rotor of Fig. 221. 



This type of winding is therefore open-circuited until the 

 brushes, bearing on the slip rings, are connected together. 



The external circuit through which these brushes are 

 connected may be of low or high resistance and thus the 



