Why is an Alternator Called an Alternator?
The term 'alternator' is used to describe what it does. Specifically, it produces an electric current that goes first in one direction and then in the opposite direction, which is known as an alternating current (AC). The word 'alternator' comes from the Latin 'alterno,' meaning 'to take turns.'
Historical Background
The term alternator originated in the early days of electricity generation, particularly in the context of automotive applications. Earlier, car batteries were charged by a DC-output generator that used commutator brushes to direct the current. However, to eliminate the wear and tear associated with these brushes, the technology evolved to use an AC-output generator with the aid of diodes for rectification. As the output was now alternating current, someone coined the term 'alternator' for the new device.
Understanding Alternators and Generators
A better question to ask might be, 'Why is an alternator sometimes called a generator?' This is because, in essence, all rotating electrical generators produce alternating current. The stator windings or rotor windings are designed to produce AC voltage. Historically, the early generators used a commutator to produce direct current (DC) output, which was labeled as 'generators.' Later, when the commutator was removed and the alternating current was harnessed directly, these machines were labeled as 'alternators.'
The term 'generator' is still sometimes used to refer to both types of machines, but this can lead to confusion. For most laypeople, it is easier to explain that both are essentially the same thing; hence, the term 'generator' is often used for convenience. However, in a technical context, it is clearer to use 'alternator' to describe machines that produce alternating current.
Modern Usage
Today, the term 'alternator' is the one most commonly used to describe the machines that produce AC power. It's important to note that, despite the name, there is no fundamental difference in the way these devices operate. Both are designed to convert mechanical energy into electrical energy, specifically alternating current.
In simple terms, an alternator generates an alternating voltage, i.e., AC. This is consistent with the technical definition of an alternating current generator. Alternately, it may also be referred to as a synchronous generator in some contexts.
In early internal combustion engine applications, the machine responsible for charging the battery was a brushed DC generator. Later, when this was replaced by an AC machine with rectified output to avoid brush wear-out, it was called an alternator. This transition highlights the shift from mechanical friction in commutator brushes to more efficient and maintenance-free AC solutions.
Thus, the term 'alternator' is a reflection of the technological evolution and the need for more efficient and robust power generation in various applications.