explain the difference between a.c and d.c generator
A.C generator: It produces an alternating current which reverses its direction continuously.
D.C. generator: To get a direct current, a split-ring type commutator must be used. The generator is thus called a D.C generator.
The only difference between a D.C generator and an A.C generator is that the two ends of the generator coil are linked to the outer circuit. In a D.C generator, we connect the two ends of the coil to a commutator consisting of two half rings of copper. Whereas in an A.C generator, we connect the two ends of the coil to two full rings of copper called slip rings. There is no commutator in an A.C. generator.