# Electric Motor : A device which convert electric energy into mechanical energy is called electric motor.

--An electric motor is an electric machine that converts electrical energy into mechanical energy.
In normal motoring mode, most electric motors operate through the interaction between an electric motor's magnetic field and winding currents to generate force within the motor. In certain applications, such as in the transportation industry with traction motors, electric motors can operate in both motoring and generating or braking modes to also produce electrical energy from mechanical energy.
Found in applications as diverse as industrial fans, blowers and pumps, machine tools, household appliances, power tools, and disk drives, electric motors can be powered by direct current (DC) sources, such as from batteries, motor vehicles or rectifiers, or byalternating current (AC) sources, such as from the power grid, inverters or generators. Small motors may be found in electric watches. General-purpose motors with highly standardized dimensions and characteristics provide convenient mechanical power for industrial use. The largest of electric motors are used for ship propulsion, pipeline compression and pumped-storage applications with ratings reaching 100 megawatt. Electric motors may be classified by electric power source type, internal construction, application, type of motion output, and so on.
Devices such as magnetic solenoids and loudspeakers that convert electricity into motion but do not generate usable mechanical power are respectively referred to as actuators and transducers. Electric motors are used to produce linear force or torque (rotary).
 

 Electric motor

 # Structure : 
* Armature coil.
* Strong magnet.
* Split ring commutator.
* Brushes.
* Battery.
# DC Generator.- A Generator which convert mechanical energy into electric energy in the form of direct current or DC is called DC generator.

 DC Generator

# AC Generator. A generator which convert mechnacial energy into electric energy in the form of alternative current is called AC Generator

-lternating current (AC, also ac), the flow of electric charge periodically reverses direction. In direct current (DC, also dc), the flow of electric charge is only in one direction.
The abbreviations AC and DC are often used to mean simply alternating and direct, as when they modify current or voltage.[1] [2]
AC is the form in which electric power is delivered to businesses and residences. The usual waveform of an AC power circuit is a sine wave. In certain applications, different waveforms are used, such as triangular or square waves. Audio and radio signals carried on electrical wires are also examples of alternating current. In these applications, an important goal is often the recovery of information encoded (or modulated) onto the AC signal.

 AC Generator.