Nowadays electricity is an indispensable part of life today, it provides us with lighting, climate control, entertainment and much more. It’s hard to imagine life without electricity. When it comes to electrical power, energy is usually converted from other forms into electricity, powering the systems and devices that we often take for granted.
Converting energy from one form to another is a way to understand the difference between electric motors and generators, an electric motor will convert electricity into mechanical energy and provide a power source for machinery. When it comes to generators, they do the opposite of this and change the mechanical energy into electricity.
Even though there’s a significant difference in the functions, electric generators and electric motors are similar when it comes to their underlying mechanisms and fundamental structure, they both rely on an important law of physics, Faraday’s Law of Electromagnetic Induction.
The Relationship Between Electricity and Magnetism
It is well known that electricity and magnetism are two manifestations of a single fundamental force called electromagnetism, which is central to the universe as we know it. The electromagnetic force is said to have existed in its current form since the big bang.
Converting Energy into Electric Energy
According to Faraday’s Law of Induction, whenever there is a change in the magnetic field across a conductor, like a wire coil, electrons will move perpendicular to that magnetic field, this will generate electromotive force, which then creates a flow of electrons. This is what’s used to create electricity in a electric generator.
To produce this magnetic flux, the magnets and the conductor are moved relatively close to one another, the wires will wind up into tight coils, increasing the number of wires and resulting in electromotive forces. By continuously rotating the coil or magnet, whilst keeping the other in place, it will give a continual flux variation. The rotating component is referred to as a ‘rotor’, whilst the stationary component is called a ‘stator’.
Electric generators come under two categories, ‘dynamos’ and ‘alternators’, dynamos direct current and alternators generate alternating currents.
The dynamo was the first form of electric generators that were useful for industrial applications, electric dynamo uses rotating coils of wire and magnetic fields to convert mechanical energy into direct currents. Originally dynamos are used for electric power generation and use steam as a source to generate the required mechanical energy.
Today, electric dynamos use outside of a few low power applications, alternators are more widespread for electricity generators. These types of generators convert mechanical energy into alternative currents. A rotating magnet serves as the rotor, turning within a set of conductor coils on an iron core which becomes a stator. As magnetic fields rotate, they generate an AC voltage in the stator. The magnetic field can be created by permanent magnets or by a field coil electromagnet.
Automobile’s alternator, as well as a central power station, provides electricity to a grid and becomes an electric generator.
From electrical energy to mechanical energy
An electric motor does the opposite of an electric generator, they turn mechanical energy into electricity and an electric motor takes electricity then converts it into mechanical energy. Electric motors can be found in a diverse range of applications, from industrial manufacturing machinery to everyday appliances, the rotor will turn a shaft to create mechanical power. Stators are made from coil windings or permanent magnets with a core of thin sheets which are layered. These are known as laminations and create less energy loss than a solid core. There’s a small air gap between a rotor and a stator, which will increase the magnet current.
Electric motors can be piezoelectric, electrostatic or magnetic, the majority of modern motors use magnets and some are designed to run on DC whilst others run on AC. You’ll find electric motors of all sizes in an impressively wide range of applications. This includes anything from small motors in watches, to electric motors that power manufacturing machinery, this technology is robust yet elegant and central to our modern life.
How this made significant changes
As mentioned, although electric motors and generators perform opposite functions, they rely on the same underlying physical principle, Faraday’s Law of Induction. During the early nineteenth century, Michael Faraday’s contributions to the study of electricity and magnetism were unparalleled. Despite having a formal education and despite the fact that the empirical study of physical phenomena was a new field of study, Faraday is one of the most influential scientists in history.
Faraday’s monumental discovery includes the magnetic fields interaction with electric currents which create an electromotive force. This has opened the door to modern electric technology that we take for granted. Faraday’s law of induction is the principle behind transformers, electric motors, generators, inductors and solenoids. Without this knowledge, we would not be able to develop reliable equipment for generating electricity to the grid. We wouldn’t have electric motors to power other machinery and the electrodynamics developed by Faraday and Maxwell were also a major catalyst for Albert Einstein’s theory of Special Relativity.
Electric motors and electric generators, regarding their functions are quite distinct from one another, however, they are similar in other ways. Both rely on the same underlying physical principle and understanding these is instrumental in the development of the most commonplace modern technology.