Speed, torque and electrical requirements are variables that are important to motor selection. Electrical engineers focus on electrical efficiency where the wire and brush material, insulation, contact arcs, etc. are all factors. With the widespread use of digital electronics many engineers concentrate on the design of motor controllers and position sensors. Industrial engineers must understand the applications and uses of various actuators in order to select the best item for a particular job. I.2 Electric Motors Electric motors convert electrical energy into rotary motion.
Magnetism is the intermediate stage.
A motor achieves continuous rotation in a manner similar to tying a carrot in front of a donkey's nose. The donkey is always trying to get the carrot, but as soon as it gets closer, the carrot moves farther away. But as soon as they get close, the magnetic field changes to a new orientation which again draws the rotor. There are a variety of motor styles, that are controlled in different manners. The basic categories are DC, AC, stepper, servo and syncro motors, each having sub categories.