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Difference between AC and DC Generator

The AC generator generates an output voltage which alters in amplitude as well as time whereas the DC generator generates a constant output voltage which does not change in amplitude as well as time.

The electrical energy we utilize has two fundamental types, one is known as Alternating while the other one is Direct. The electric power in homes has alternating current and voltages, but in an automobile currents and voltages are constant. Both types have their own particular uses whereas the technique of producing the both is same, which is called electromagnetic induction. The machines which produce an electric power are called generators, and AC and DC generators are different from each other by the method they apply to pass the produced current to the external circuit.

The key differences between AC and DC Generator are discussed here on the basis of real-world factors such as output power, current induction type, brushes & maintenance, voltage level, commutation process, and types.The following table presents the key differences between AC Generator and DC Generator.

Difference between AC Generator and DC Generator

Characteristics AC GeneratorDC Generator
Output PowerGenerates AC electric powerProduces DC electric power
Ringsit has slip-ringsit uses a split-ring commutator
Current induction Output current can be induced either in the rotor or in the statorOutput current is induced in the rotor ONLY
BrushesSlip-rings have smooth and uninterrupted surfaces, which allow the brushes to remain in contact uninterruptedly with the slip ring surfaces.
Hence, the brushes do not wear as quickly as in case of a DC generator and there is almost no possibility of a short circuit.
Commutators and brushes wear out very quickly thus a short circuit is possible in the commutator because of sparking.
MaintenanceRequires very less maintenance and thus more reliable than a DC GeneratorIt requires frequent maintenance
Voltage LevelUsed to generate very high voltagesUsed to generate comparatively lower voltages
CommutatorsIt Does not have commutatorsIt possesses commutators in order to counter the changing polarities effect.
Voltage DistributionAC voltage can be distributed quite easily using transformers.DC Voltage is comparatively difficult to distribute efficiently.
TypesRotating armature, Rotating field
Single phase, Three phase
Permanent magnet, Separately-excited, Self-excited

About Ahmad Faizan

Mr. Ahmed Faizan Sheikh, M.Sc. (USA), Research Fellow (USA), a member of IEEE & CIGRE, is a Fulbright Alumnus and earned his Master’s Degree in Electrical and Power Engineering from Kansas State University, USA.

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