12 July 2019

Alternator vs generator

The major key difference between the alternator and generator is that generator armature is stationary and the field is stationary whereas the generator is that in alternator the armature is stationary and the field rotates. That has both of function of converting the mechanical energy into the electrical energy. The generator is the device which converts the mechanical energy into the electric current while the generator is the alternator is a device which converts mechanical energy into the electrical energy.

Definitions of alternator:

An alternator is a machine which converts the mechanical power from a prime mover to AC electrical power at a specific voltage and frequency. For bulk power generation large alternator is used in thermal and hydro, nuclear power station.

Definition of generator:

A generator converts mechanical energy into electrical energy or power. The working of the generator is based on the principle of Faraday laws of electromagnetic induction. 

The main key difference between alternator and generator are given below.

  • The alternator takes input supply from the stator,  the generator takes input supply from the rotor.
  • An alternator is a machine which converts the mechanical energy from a prime mover into the AC, whereas the generator converts the mechanical energy from the prime mover into an AC or DC.
  • The alternator induces the AC whereas the generator causes both AC and DC power. 
  • The generator produces a current which can either be alternating current or the direct current while in the generator only produce alternating current.
  • The armature of an alternator is stationary while in generator it is rotating.
  • The alternator has a wide range of RPM, the generator has a narrow range of RPM.
  • The output of the alternator is higher than compared to the generator.
  • The alternator is smaller in size and requires less space whereas the generator requires large space.
  • The output EMF of the alternator is variable and the output voltage of the generator is constant.
  • The alternator does not charge the completely dead battery while the generator charges the dead battery.
  • The alternator is energy efficient as they only use the required energy, whereas the generator utilizes all the energy that is produced.
  • The alternator has a rotating magnetic filed whereas the generator has a rotating magnetic field for the high voltage generation and low voltage stationary magnetic field is used.
  • There is no need for the polarization of alternator after installation, whereas the polarization is necessarily required after the installation of the generator. 
  • The generator produces the voltages all day long continuously while an alternator produces voltages only when it is required.