Dynamo vs Alternator
Remember the device fitted in the bicycle of your grandfather that made the light bulb fitted in front of the bicycle to light up when he peddled the bicycle? It was a dynamo that was capable of converting mechanical energy into electrical energy. A dynamo is nothing but an electric generator, and was the main source of power for the industries till alternators came along. Though technically speaking, both a dynamo as well as an alternator is electric generators producing electric current, there is difference between dynamo and alternator that will be discussed in this article.
Dynamo
Dynamo makes use of rotating coils of wire in addition to magnetic fields to produce direct current converting mechanical energy into electric energy. It is based upon Michael Faraday’s law of induction. It consists of a magnetic field produced by a stationary stator and rotating windings called armature. The armature rotates causing electrons in the wires to move out because of the push of the magnetic field thus producing an electric current. This current is direct current because of the use of a commutator that performs the role of a rotary switch. Commutator reverses the direction of the alternating current that is produced by the dynamo. This was done because in earlier times, there was no use of alternating current and the current produced from dynamo was a good replacement of batteries.
Alternator
Modern generators are also known as alternators that convert mechanical energy into electrical energy (alternating current). However, it has come to refer small machines fitted alongside engines of automobiles. Engines of automobiles rotate these alternators. However, in large power stations these alternators are driven by steam engines called turbines.
In automobiles, alternators keep on charging the battery and also provide power for the electrical system of the car such as headlights and horn.
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In brief: • Take out the commutator from the dynamo, and it becomes an alternator. • Whereas dynamos produce direct current, alternators produce alternating current • Because of the dominance of alternating current, dynamos are not used any more and even automobiles make use of alternators that charge the battery and provide the current for the electrical systems of the car when the engine is running • An alternator gives same performance at all speeds whereas a dynamo produces good current at high speeds.
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