Stamford Alternators

Electric generators are very useful machines when it comes to a possible failure in the usual supply of electrical energy. Of course, there are countless models on the market, which vary in terms of their technical specifications. But they all have one component in common: an alternator. Our models, for example, have Stamford alternators.

Without this Item or without alternators, an electric generator would be nothing more than an engine that moves without going anywhere. Generators are, as it were, the fundamental element that allows an electric generator to perform its function efficiently, in other words, to provide safe and reliable electrical energy.

Next, we will have look at alternators. We will investigate alternator operation and its parts, as well as the physical principle by which they generate electrical energy. We will ask ourselves, of course, why in terms of generators it is appropriat to have a Stamford alternator. We will check its history and what are the advantages of having a Stamford alternator.

Table of Contents

parts for an electric generator

What are alternators?

To put it briefly, alternators are machines capable of transforming mechanical energy into usable electrical energy. This task is why they are considered the fundamental component of any electric generator. These transform the mechanical power provided by an engine (which can be powered by gasoline, gas or diesel) into electrical power, in the form of alternating current.

Its history dates back to the 19th century, when Faraday, the physicist who postulated the law that we will explain in detail later, designed the Faraday disk. This invention consisted of a copper disk that rotated between the ends of a horseshoe-shaped magnet.

Faraday noticed that magnetism had to do with the generation of electricity: the phenomenon of electromagnetic induction was taking place and thereby electromagnetism began.

What is electromagnetic induction?

Electromagnetic induction is the phenomenon by which an electric current is induced through a change in the magnetic field. Basically, this phenomenon consists of the dragging of free electrons in a conductive material, which are "dragged" by the moving magnetic forces.

Faraday's Law

When Faraday noticed that an electric current was produced as a result of the movement of a magnetic field, he tried to explain the phenomenon. This way, he ended up formulating the following law: there is a proportionality relationship between the speed of movement of a magnetic field and the tension induced by it in a conducting material.

So how does an alternator work?

Taking into account what the phenomenon of electromagnetic induction consists of, it is easy to understand how an alternator works, this is the application of such a phenomenon. It was said that the movement of a magnetic field "drags" free electrons from a material.

So, in practice, An alternator must have two essential parts: the rotor and the stator. Why? Because one of its components must generate the moving magnetic field (the rotor, or mobile inductor); and another component must act as a material whose electrons are dragged (the stator, or fixed armature).

The rotor has a number of magnetic poles inside it. They are always even numbers and they are usually four. These are responsible for the magnetic field. And how does such a field move? The engine is responsible for this, which rotates at more than 1800rpm, and provides that mechanical energy that will be transformed.

Inside the stator, whose walls are made up of a winding of conductive materials (usually copper), the rotor moves. It is very important that there is an empty space between the rotor and the stator, so that the mechanical energy is converted into electrical energy in the most efficient way possible.

Why do we have a Stamford alternator on our generators?

Stamford alternators have been produced since 1904. For almost 120 years, Cummins Generator Technologies, the company that currently manufactures them worldwide, has designed, produced and manufactured hundreds of thousands of alternators.

They are specialized in the production of alternators for electrical generation systems. With a solid winding, the enormous power that this implies can manage more than 60KW. However, the list of advantages it offers is substantial.

Stamford alternators AVR regulation system

This system is as simple as it is effective. It works by applying Faraday's law. How? We know that the greater the angular speed of the movement of a magnetic field around a conductive material, the more its free electrons are stimulated; in other words, there is a higher induced voltage.

The AVR system intervenes directly in the angular speed. In other words, it reduces or increases the amount of engine rpm, which means an increase or decrease in the current that finally, is delivered by the electric generator according to the energy demands that are presented to it.

Although this system is not the most efficient in low power generators, it is very functional and reliable in high power diesel generators. The voltage regulation has a value of ±0.5%. This means that power spikes are not a concern even when power over 60KW is offered.

Stamford alternators class H insulation system

Compared to class F or class B insulation, class H is more efficient and profitable for rotating machines, such as electric generators. But what advantages does class H insulation brings? The main incidence of this type of insulation is evident in the long useful life of the machine: it is estimated that some 20,000 more hours.

An alternator that has a class H insulation system can operate at extreme temperatures, close to 180°C. At the same time, it will allow the generator a higher 9% power than another generator with a different insulation class.


Stamford alternators are known worldwide for the wide variety of models found on the market. The current that is generated is sufficient to cover the demand that can range from 7.5 to 500 KvA. Or in terms of power, the Stamford models offer power ranging from 6KW to 140KW.

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