Explain the working of an A.C generator with neat diagram
Answers
working of an AC generator :
An electric motor consists of a rotating rectangular coil ABCD placed between the two poles of a permanent magnet . The two ends of this coil are connected to the two rings R1 and R2 . The inner side of these rings are made insulated . the two conducting stationary brushes B1 and B2 are kept pressed separately on the rings R1 and R2 , respectively . The two rings R1 and R2 are internally attached to an axle . The axle may be mechanically rotated from outside to rotate inside the magnetic field . Outer ends of the two brushes are connected to the galvanometer to show the flow of current in the given external circuit .
when the axle attached to the two rings is rotated such that the arm AB moves and CD moves down in the magnetic field produced by the permanent magnet . let us say the coil ABCD is rotated clockwise in the arrangement . by applying fleming ' s right hand rule , the induced currents are set up in these arms along the directions AB and CD . Thus an induced current flows in the direction ABCD . If there are larger number of turns in the coil , the current generated in each turn adds up to give a large current through the coil . This means that the current in the external circuit flows from B1 and B2.
After half rotation , arm CD starts moving up and AB moving down . As a result , the directions of the induced currents in both the arms change , giving rise to the net induced current in the direction DCBA . The current in the external circuit now flows from B1 and B2 . Thus after every half rotation the polarity of the current in the respective arms changes . such a current , which changes direction after equal intervals of time , is called an alternative current . this device is called AC generator .