DIRECT CURRENT GENERATORS 75 



Baking Commutator 



To bake the commutator on a commutating pole 

 machine, the brushes should never be shifted under 

 load to produce sparking and heating. They should 

 always be shifted at no-load to insure against setting 

 them beyond the safe limit of no-load commutation, 

 thus preventing flash-over should the load be suddenly 

 removed. When baking a commutator, it should also 

 be remembered that the armature must not be short 

 circuited through the commutating pole winding, as 

 in this case the majority of machines will build up as 

 series generators and the armature current cannot 

 then be controlled. 



