Consider the various configurations discussed in Page 443 of

Consider the various configurations discussed in Page 443 of your text for a DC motor. Which one will you choose to get Constant operating torque For the motor used in hard disk drive or DVD player

Solution

a) From the speed - torque characteristics, DC shunt motor is best suited motor for constant torque applications.

b) Stepper motor is used in DVD Players and hard disk because it not only offers variable speed but also better control.