Floppy disk drive motor. View of the electric motor from a computer floppy disk drive. The turntable has been removed to show the interior. The central hole contains the spindle on which the turntable turns. Around the hole are 12 small electromagnets, composed of copper wire wound around metal bars. These electromagnets are sequentially fed with current which generates a magnetic field. This interacts with permanent magnets on the turntable (not seen), causing it to spin at a constant speed. Floppy disks are used to store data independently of the computer's hard disk.