A generator is an electrical machine which converts mechanical energy into electrical energy. Generator is of two types, AC generator and DC generator. A DC generator is a generator which produces direct current (DC). The energy conversion is based on principle of faraday law of electromagnetic induction.
Faraday Law of Electromagnetic Induction
According to faraday law, if varying magnetic flux link with conductor EMF being induced in conductor and if conductor circuit is closed, electric current will produced be in the conductor and its direction is defined by fleming’s Right hand rule.
Fleming’s Right Hand Rule
Fleming rule shows relation in three things ,magnetic flux, current direction ,and electromagnetic force. According to right hand rule if right hand’s first three finger taking each other perpendicular .first finger or thumb shows EMF (electro magnetic force) and second finger shows magnetic field and last one shows electric current direction . Magnetic force and electric current direction is opposite to each other, so this rule shows relation among these.
Principle of DC Generator
When a conductor rotate in magnetic field it cuts magnetic field due to which an EMF induced in conductor .If conductor circuit being closed the current will flow in the circuit. In this way mechanical energy is converted into electrical energy.
Actually in this way as simply we will say that prime mover rotation is converted into electricity. We give rotation to generator by prime mover and generator produces electricity and this electricity is used in electrical devices like motor, tube-light, fan, etc.