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Electric Generator Servicing, Generator Overhauling

The Difference Between An AC & DC Generator

While it is known to many that an Alternating Currents (AC) generator and Direct Currents (DC) generator are quite different from each other, people do not actually know the actual reasons that separate the two from each other.

Industrial customers, plant owners and many other employers in the electrical engineering industry should be aware of the differentiating reasons so they will in the future, understand which type of generator to use. By identifying the right type, you will know when is the appropriate time to seek electric generator servicing when the time calls.

How It Works

AC Generator

The magnet’s north and south poles in an AC generator cause the electrical current in an AC generator to flow in the opposite direction, converting mechanical energy into AC electrical power.

DC Generator

Unlike AC generators, the current that flows through the coil, revolves in a fixed field, with both ends of the coil being attached to a commutator. The purpose of the commutator is to balance the charges leaving and re-entering the generator, to create a current that flows in a single direction.

Efficiency Of Brushes

AC Generator

This type of generator has slip-rings and with its smooth and steady surface, it ensures that the brushes are always kept in contact with the slip ring surfaces.

To put it simply, it is the main reason why brushes have a longer life and higher efficiency as they do not deteriorate at a fast rate and the chances of a short circuit are extremely low with slip-rings being present.

DC Generator

DC generators, on the other hand, do not have slip-rings so commutators and brushes eventually wear out pretty quickly and are generally less efficient than AC generators.

However, sometimes these brushes do not just detoriate but may affect the overall health condition of the generator resulting in failure. In cases like these, a generator overhauling will need to be done to throughly check the parts of the device. If there are any faults, a quick repair or replacement can be done quickly by a qualified engineer.


AC Generator

The construction of an AC generator is fairly simple as it only comprises a single moving part which is the rotor itself. Hence, the costs are lesser than DC generators and they require lesser maintenance as well.

DC Generator

DC generators are fixed with commutators and carbon brushes and as said earlier on, they wear out fast. And that only means that over time, they will have to be replaced to extend the life of the generator. So, unlike AC generators, they will require more maintenance as time passes.

Produced Voltage

AC Generator

AC generators are able to generate a high amount of voltage which varies in time and amplitude. The typical output frequency will range from about 50Hz to 60Hz.

DC Generator

However, DC generators produce comparatively lower voltages if you compare it with AC generators as it remains constant in time and amplitude. The output frequency for the generator is zero.


AC Generator

There are many types of AC generators, with a wide range consisting of various types like single phase generators, induction generators, 3 Phase generators, synchronous generators and so on.

DC Generator

There are primarily two types of DC generators, the separately excited DC generator and self-excited DC generator. In the DC series, they are better known as the shunt or compound generator, respectively.


AC Generator

Best used for home purposes, AC generators operate specifically to power common electrical appliances and smaller motors such as electrical fixtures, vacuum cleaners, juicers and food mixers.

DC Generator

This type of generator is used to power huge electric motors, in particularly those that will need to be used for subway systems. Additionally, these generators give an efficient and reliable energy supply that can charge a large number of batteries used for off-grid and mobile uses.

As long as you are in the electrical engineering industry, you will definitely need to know the main differences between an AC and DC generator. You do not want to end up with a generator that will be of any use to your business so know these key differences and make sure you have the right type of generator in your workplace or plant.

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