Difference Between Alternator and Generator


Main Difference

Alternator and Generator are two types of machines that have the sole function of converting the mechanical energy into the electrical energy. The difference between both these devices comes due to their mechanism and the type of electric current they produce following it. The Generator is the device which converts the mechanical energy into the electrical energy (either electric current or direct current). On the other hand, the alternator always produces the alternating current. It won’t be wrong to say that alternator is the type of generator that converts mechanical energy into the electrical energy in a way so that it produces the alternating current.

Comparison Chart

Energy Efficient
Polarization after installation
Only when required.Everytime.

What is Alternator?

The alternator is a type of generator that produces the alternating current; like a generator, the alternator also follows the mechanism of converting the mechanical energy into the electric energy. The thing which separates alternator from the generator is the specific current it produces, and it is due to the difference in the parts used for spinning and fixation purpose. The alternator has more of its use in the automobile industry, where using this device the mechanical energy of the engine is converted into the mechanical energy so that the recharging of the battery in the cars takes place. In the alternator, the mechanical energy is utilized to rotate the magnet so that the wires are kept stationary. The spinning of the magnetic field alongside the stator causes the change in the magnetic flux which leads to the production of the current. After the current is produced, the alternators directly give out the current without converting it into the Direct Current (DC). The alternators are the energy-efficient devices as they only produce the energy when it is required. It won’t be wrong to say that, they are the modern version of the generator that works on the aim of utilizing the energy to best and wasting it to the minimum. After alternators are installed, no polarization is required. A precaution which is always there while using the alternator is that it is not for charging the dead battery, and if one tries to do so the battery can burn out and can also cause damage to the surroundings.


What is Generator?

The generator is the device that converts the mechanical energy into the electrical energy; the current it produces can either be the direct current or the alternating current. The working mechanism of the generator is what separates it from the alternator. The rotor, which is formed of the coils of wires, is fixed inside the magnetic field. The spinning of the windings of wire spin generates the electricity. The stationary magnet forms the magnetic field, and the mechanical energy of the engine is used to rotate the armature. As the generator produces uses voltage all the time and uses all the produced energy, they are ideally used for the production of electricity at large scale. They also require the large space for running its operations. Therefore, they are seen at the dams, where there is more area (land), and excessive electricity production is the purpose. Unlike alternators, generators are polarized necessarily after the installation. The generator can even be used to charge the dead batteries. The DC in the generator is produced after the rotor is attached to the commutator. It will be pertinent to mention here that commutator is an integral part of the DC production here, it is made up of the set of the split rings, which connect the generator the external circuit in such a manner that the current produced is always the direct current.

Alternator vs. Generator

  • In an alternator, the spinning of the magnetic field alongside the stator causes the change in the magnetic flux, which leads to the production of electricity. On the other hand, in the generator, the rotor is fixed in the magnetic field, and the spinning of the windings generates the electricity.
  • The generator produces a current which can either be alternating current or the direct current. Contrary to this, the alternator only produces alternating current.
  • Alternators are energy –efficient as they only use the required energy, whereas generators utilize all the energy that is produced.
  • The alternators can’t be used for charging the dead battery; their usage can even cause the burning of the battery. Conversely, the generators are even suitable for charging the dead batteries.
  • There is no need of polarization of alternators after installation, whereas the polarization is necessarily required after the installation of the generator.
  • The generator produces the voltages all the day long continuously, while an alternator produces voltage only when it is required.
Harlon Moss

Harlon currently works as a quality moderator and content writer for Difference Wiki. He graduated from the University of California in 2010 with a degree in Computer Science. Follow him on Twitter @HarlonMoss