Dc And Ac Generators Pdf

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The initial electromagnetic generator Faraday disk was invented by British scientist namely Michael Faraday in the year A DC generator is an electrical device used for generating electrical energy. The main function of this device is to change mechanical energy into electrical energy. There are several types of mechanical energy sources available such as hand cranks, internal combustion engines, water turbines, gas and steam turbines.

The generator provides power to all the electrical power grids. The reverse function of the generator can be done by an electric motor. The main function of the motor is to convert electrical energy to mechanical. Motors, as well as generators, have similar features.

This article discusses an overview of DC generators. A DC generator or direct current generator is one kind of electrical machine, and the main function of this machine is to convert mechanical energy into DC direct current electricity.

The energy alteration process uses the principle of energetically induced electromotive force. This electromotive force can cause a flow of current when the conductor circuit is not opened.

A DC generator is also used as a DC motor without changing its construction. The construction of a 4-pole DC generator is shown below. But the two essential parts of this device are the stator as well as the rotor.

The stator is an essential part of the DC generator, and the main function of this is to provide the magnetic fields where the coils spin. This includes stable magnets, where two of them are with reverse poles facing.

These magnets are located to fit in the region of the rotor. Rotor or armature core is the second essential part of the DC generator, and it includes slotted iron laminations with slots that are stacked to shape a cylindrical armature core. Generally, these laminations are offered to decrease the loss because of the eddy current.

The armature core slots are mainly used for holding the armature windings. These are in a closed circuit winding form, and it is connected in series to parallel for enhancing the sum of produced current.

The external structure of the DC generator is Yoke, and it is made with cast iron otherwise steel. It gives the necessary mechanical power for carrying the magnetic-flux given through the poles. These are mainly used to hold the field windings. In addition, the poles will give joint toward the yoke with the welding method otherwise by using screws. The pole shoe is mainly utilized for spreading the magnetic flux as well as to avoid the field coil from falling.

The working of the commutator is like a rectifier for changing AC voltage to the DC voltage within the armature winding to across the brushes.

It is designed with a copper segment, and each copper segment is protected from each other with the help of mica sheets. It is located on the shaft of the machine. The main function of the commutator in the dc generator is to change the AC to DC. It acts like a reversing switch and its role in the generator is discussed below. The emf which is induced within the armature coil of the generator is alternating.

So, the flow of current within the armature coil can also be alternating current. This current can be reversed through the commutator at the accurate moment once the armature coil crosses the magnetic unbiased axis. Thus, the load attains a DC or uni-directional current. The commutator guarantees that the flow of current from the generator will flow forever in a single direction. The electrical connections can be ensured between the commutator as well as the exterior load circuit with the help of brushes.

When a conductor is located in an unstable magnetic field, an electromotive force gets induced within the conductor. The induced e. If the conductor is present with a closed lane, the current which is induced will flow in the lane. In this generator, field coils will generate an electromagnetic field as well as the armature conductors are turned into the field.

Therefore, an electromagnetically induced electromotive force e. The classification of DC generators can be done in two most important categories namely separately excited as well as self-excited.

In separately excited type, the field coils are strengthened from an autonomous exterior DC source. In the self-excited type, the field coils are strengthened from the generated current with the generator. The generation of the first electromotive force will occur because of its outstanding magnetism within field poles.

The produced electromotive force will cause a fraction of current to supply in the field coils, therefore which will increase the field flux as well as electromotive force generation. Further, these types of dc generators can be classified into three types namely series wound, shunt-wound, and compound wound. There are different kinds of machines available in the market where the total input energy cannot be changed into output due to the loss in the input energy.

So different losses can occur in this type of generator. For generators like shunt-wound, the field copper loss is equivalent to Ish2Rsh which is almost stable. For generators like a series wound, the field copper loss is equivalent to Ise2 Rse which is also almost stable. For generators like compound-wound, the filed copper loss is similar to Icomp2 Rcomp which is also nearly stable.

This loss mainly occurs because of the reversal of the armature core. Whenever the core supplies below one set of poles, then the core will finish one series of frequency reversal.

This huge current is known as eddy current whereas the loss is called the eddy current loss. Stray losses mainly occur by combining the losses like core as well as mechanical. These losses are also called rotational losses. Generally, generators are classified into two types like AC and DC.

The main function of these generators is to change the power from mechanical to electrical. An AC generator generates an alternating current whereas the DC generator generates direct power. This law tells that once a conductor shifts within a magnetic field then it slashes magnetic lines of force to stimulate an EMF or electromagnetic force within the conductor.

Once the circuit of the conductor is closed then the emf can cause flow of current. These differences can assist students to study about this topic but before that, one should know about the AC generators as well as dc generators in every detail so that differences are very simple to understand. The characteristic of the DC generator can be defined as the graphical representation among the two separate quantities.

The most essential characteristics of this generator are discussed below. The magnetization characteristics provide the difference of producing voltage otherwise no-load voltage through field current at a stable speed.

This kind of characteristic is also known as an open circuit otherwise no-load characteristic. The load or external type characteristics provide the main relationships among the load current as well as terminal voltage at a stable speed. The applications of different types of DC generators include the following.

Thus, this is all about the DC generator. Here is a question for you, what are the disadvantages of DC generators?

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In electrical engineering , an armature is the component of an electric machine which carries alternating current. The armature can be on either the rotor rotating part or the stator stationary part , depending on the type of electric machine. The armature windings interact with the magnetic field magnetic flux in the air-gap; the magnetic field is generated either by permanent magnets, or electromagnets formed by a conducting coil. The armature must carry current , so it is always a conductor or a conductive coil, oriented normal to both the field and to the direction of motion, torque rotating machine , or force linear machine. The armature's role is twofold.

An alternator is an electrical generator that converts mechanical energy to electrical energy in the form of alternating current. In principle, any AC electrical generator can be called an alternator, but usually the term refers to small rotating machines driven by automotive and other internal combustion engines. An alternator that uses a permanent magnet for its magnetic field is called a magneto. Alternators in power stations driven by steam turbines are called turbo-alternators. Alternating current generating systems were known in simple forms from the discovery of the magnetic induction of electric current in the s.

DC is the kind of electricity made by a battery with definite positive and negative terminals , or the kind of charge generated by rubbing certain types of materials against each other. Certain sources of electricity most notably, rotary electromechanical generators naturally produce voltages alternating in polarity, reversing positive and negative over time. Whereas the familiar battery symbol is used as a generic symbol for any DC voltage source, the circle with the wavy line inside is the generic symbol for any AC voltage source. One might wonder why anyone would bother with such a thing as AC. It is true that in some cases AC holds no practical advantage over DC. In applications where electricity is used to dissipate energy in the form of heat, the polarity or direction of current is irrelevant, so long as there is enough voltage and current to the load to produce the desired heat power dissipation. However, with AC it is possible to build electric generators, motors and power distribution systems that are far more efficient than DC, and so we find AC being used predominantly across the world in high power applications.

What is a DC Generator : Construction and Its Working

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Generators are useful appliances that supply electrical power during a power outage and prevent discontinuity of daily activities or disruption of business operations. Generators are available in different electrical and physical configurations for use in different applications. In the following sections, we will look at how a generator functions, the main components of a generator, and how a generator operates as a secondary source of electrical power in residential and industrial applications.

The rotating machines function on the same principle of electromagnetic induction those are the motor and the generator. Even though the principle is the same their the output they deliver differs due to the operational difference. This difference in operation is important for the machines to be classified as either a motor or a generator. Similarly, the individual machines can also be classified as ac or dc typed depending on the input and output they deliver.

A dc generator is an electrical machine which converts mechanical energy into direct current electricity.


The electric generator was invented before the correlation between electricity as well as magnetism was discovered. These generators use electrostatic principles to operate with the help of plates, moving belts which are charged electrically as well as disks to carry charge toward an electrode with high potential. Generators use two mechanisms to generate the charge like the triboelectric effect otherwise electrostatic induction. So, it generates low current as well as very high voltage due to the complexity of insulating machines as well as their inefficiency. The power ratings of Electrostatic generators are low so they never utilized for electrical power generation. The practical applications of this generator are to supply power to X-ray Tubes as well as in atomic particle accelerators. An alternate name of an electric generator is a dynamo for transmission as well as the distribution of energy over power lines to different applications like domestic, industrial, commercial, etc.

The initial electromagnetic generator Faraday disk was invented by British scientist namely Michael Faraday in the year A DC generator is an electrical device used for generating electrical energy. The main function of this device is to change mechanical energy into electrical energy. There are several types of mechanical energy sources available such as hand cranks, internal combustion engines, water turbines, gas and steam turbines. The generator provides power to all the electrical power grids. The reverse function of the generator can be done by an electric motor.

General Information: Emergency Contact: Email: contactus powerplus. Is your business in need of an AC generator or a DC backup generator? Can you tell the difference between the types of generators available on the market and which one best fits your needs? Here is what you need to know so you can invest in the right generator for your business. In order to determine which generator you need, you should understand a few things first. For example, how do they work? What are the differences between AC and DC?

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Contrast Between AC and DC Generator

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What is an Electric Generator and Its Working

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