Describe the working of an AC generator with the help of a labeled circuit diagram. What changes must be made in the arrangement to convert it to a DC generator?
ABCD is rectangular coil placed between the two poles of a permanent magnet.
• Arms AB of coil is attached to a ring R1 and arm CD is attached to the ring R2.
• R1 and R2 are insulated from inside and are attached to an axle.
• A brush B1 touches R1 and another brush B2 touches R2.
• A galvanometer is connected to B1 and B2 to show the flow and direction of current in the circuit.
Working of AC Generator:
• AC generator works in Fleming’s Right Hand Rule.
• When coil is rotated within the magnetic field, electric current is induced in it.
• Let us assume that the coil is rotating clocking in this figure. This means, AB is moving up and CD is moving down.
• When AB is moving up, current flows in it from A to B.
• When CD is moving down, current flows in it from C to D.
• After half a turn; relative positions of AB and CD change. Now, CD is moving up hence current is moving from D to C. Similarly, AB is moving down hence current is moving from B to A.
• So, after every half turn the direction of current changes in this generator. This means alternating current is being generated.
Conversion of AC generator to DC generator: For this, a split ring commutator is used in place of two separate rings. A split ring commutator maintains the direction of current in one direction and it becomes a DC generator
