ofcourse... constructionally nodifference between generator and motor.... the same machine can be used interchangable as a generator or as a motor... motor operates on the principle that when a current carrying conductor is placed in a magnetic field a mechanical force experiences on it.. a dc machine can work as a dc generator when it is driven by a prime mover and is working on the principle that when a conductor is moving in a magnrtic field an emf is generated in it ..