Generator and Alternator.
Generators convert mechanical energy into electrical energy, and Alternator also converts mechanical energy into electrical energy but there is a difference between both.
The generator and alternator are functionally the same but the only difference is construction. The generator persists a stationary magnetic field and rotating conductor which rolls on the armature with slip rings and brushes.
Hence it converts the induced emf into dc current for external load whereas an alternator has a stationary armature and rotating magnetic field for high voltage and for low voltage it has vice versa.