Machines that convert mechanical energy into electrical energy are termed as generators. Generators are of two types alternating current and direct current generators. The significance of the first ones is incomparably larger, but others still also have vast applications. Let us now discuss what is the difference between AC and DC generator.
What is an AC Generator?
A generator that converts mechanical energy into electrical energy in the form of alternating current is termed as an AC generator. The principle on which, AC generator works is Electromagnetic Induction.
What is a DC Generator?
A machine that converts mechanical energy into DC (direct current) electricity is a DC generator. DC generator uses the principle of energetically induced electromotive force.
Difference between AC and DC generator
The important difference between AC and DC generator
|Parameters||AC Generator||DC Generator|
|Output Power||It generates AC electric power||It produces DC electric power|
|Rings||They have slip-rings.||They have split-ring commutators.|
|Current induction||Its output current can be induced either in the rotor or in the stator||Its output current is induced in the rotor only|
|Direction of Current||Electrical current reverses direction periodically.||Electrical current flows only in one direction.|
|Commutators||AC generator does not have commutators.||DC generators have commutators due to which the current flow only in one direction.|
|Distribution and Transmission||The distribution of the output is easy.||It is difficult to distribute the output.|
|Efficiency||AC generators are very efficient as the energy losses are less.||Due to sparking and other losses like copper, eddy current, mechanical, and hysteresis losses DC generators are less efficient.|
|Maintenance||Requires very less||It requires frequent maintenance|
|Direction of Current||In an AC generator, the electrical current reverses direction periodically.||The electrical current flows only in one direction.|
|Types||Rotating armature, Rotating field Single-phase, Three-phase||Permanent magnet, Separately-excited, Self-excited|
|Voltage Distribution||Transformers are used to distribute AC voltage.||Transformers are not used to distribute DC voltage.|
|Voltage Level||They are useful to generate very high voltages||They are used to generate lower voltages|
As we have now understood about the difference between AC and DC generator, let us now discuss more Ac and Dc generator in detail.
A machine that converts mechanical energy into electrical energy is termed as AC generator or alternators, is a. The electrical energy generated is in the form of an alternating current sinusoidal output waveform. Steam turbines, gas turbines, and combustion engines usually supply mechanical energy.
Field, armature, prime mover, rotor, stator, slip rings are the various components of an AC generator. The principle on which AC generator works is Faraday’s law of electromagnetic induction, which states that electromotive force -EMF or voltage – is generated in a current-carrying conductor that cuts a uniform magnetic field can either be achieved by rotating a conducting coil in a static magnetic field, or by rotating the magnetic field that contains the stationary conductor.
An electrical machine whose, main function is to convert mechanical energy into electricity termed as a DC generator. An emf will be generated based on the electromagnetic induction principle of Faraday’s Laws when the conductor slashes magnetic flux. The electromotive force generated can cause a flow of current when the conductor circuit is closed.
According to Faraday’s law of electromagnetic induction, we know that when a current-carrying conductor is placed in a varying magnetic field, an emf is induced in the conductor. According to Fleming’s right-hand rule, the direction of the induced current changes whenever the direction of motion of the conductor changes.
Let us consider an armature rotating clockwise and a conductor at the left moving upwards. When the armature completes a half rotation, the direction of the motion of the conductor will be reversed downward. Hence, the direction of the current in every armature will be alternating. However, with a split ring commutator, when a current reversal occurs the connections of the armature conductors get reversed. Therefore, we get unidirectional current at the terminals.
FAQs about AC and DC generator
Q1. What factors do the generated EMF in an alternator depend upon?
Answer: The generated EMF depends on the number of armature coil turns, magnetic field strength, and the speed of the rotating field.
Q2. What are the disadvantages of AC generators?
Answer: Generating large-scale AC power using AC generators can be extremely hazardous. In the AC generator, the flow of electricity through the generator and transformer coils produces resistive heat. This resistive heat can damage the insulation and cause a fire.
Q3. What is the power factor?
Answer: The ratio between kilowatts (kW) and kilovolt amps (kVa) that is drawn from an electrical load is a power factor. The generators connected load determines it. Generators, which have higher power factors, are more efficient in transfer energy to the connected load, while generators with a lower power factor are not as efficient and result in increased power costs.