Tue February 07, 2012 By: Deepika Bhaskaran

what is the diffrence between ac generator and dc generator and where is it used

Expert Reply
Tue February 07, 2012
ac generator generates ac current which changeswith time and also its direction after a certain interval of time.
dc generator generates dc current which remains  constant with time.
Now in case of AC generator, two slip rings each one connected to each end of the armature ie A and B. Suppose arm AB is connected to A and arm CD to B. Also there are brushes B1 always in contact with respective arms.
so as the coil rotates and the arms changes their positions,the direction of current changes through them as well as in the out put.
but in dc Instead two slip rings, we have to use only one ring but that has to be split into. This split ring as it rotates touch the brushes alternatively. That the one rises up would always be in contact with one half of the ring and so with one brush and the other going down would be in contact ever with the other brush. so as the arms rotate they touch the other brushes. so although the direction of current changes in those arms,by that time they are connected to the other brushes, so the direction of output current remains same. IF U SEE THE DIAGRAM THEN U WILL REALISE AS THE ARMATURE ROTATES, RING ALSO ROTATES AND CHANGES POSITION.
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