An electric motor converts electrical energy into mechanical energy. Most electric motors operate through interacting magnetic fields and current-carrying conductors to generate force, although a few use electrostatic forces. The applications of electric motors are very diverse from industrial fans, blowers and pumps, machine tools, to household appliances, such as washers, dryers, garage door openers, and power tools; from office machines for copying and printing to computer disk drives and colling fans.
An electric motor may be powered by direct current (DC) from a battery or by alternating current (AC) from a central electrical distribution grid. It can be small enough to fit into an electric analog wristwatch. It may be enough to fill up a room to power a train or a ship. Its power rating may range from micro watts to millions of watts. Electric motors may be classified by the source of electric power, by their internal construction, by their application, or by the type of motion they give.
The categories of electric motors may include
- DC motors: Most of DC motors are Permanent-magnet motors: Brushed DC motors, Brushless DC motors, Coreless or ironless DC motors, pancake DC motors.
- Universal motors: Motors designed to operate on either AC or DC power.
- AC motors include AC Motor with sliding rotor, Synchronous electric motor, Induction motor, Doubly-fed electric motor, and Singly-fed electric motor.
- Other more common motors include Servo motor, Electrostatic motor, Torque motor, Stepper motor, Linear motor, Nanotube nanomotor, Spacecraft propulsive motor.
The reverse process, producing electrical energy from mechanical energy, is accomplished by some type of generator such as an alternator or a dynamo.