The compound wound motor is further categorised into short-shunt and long … Contact online >>
The compound wound motor is further categorised into short-shunt and long
A DC generator requires MMF to establish flux in its magnetic circuit. The MMF necessary to establish flux in the magnetic circuit of a dc generator is obtained by field excitation.
When a DC voltage is applied to the field windings of a DC generator, current flows through the windings and sets up a steady magnetic field. This is called field excitation.
Please go through the construction of dc generator before reading this article about different types of dc generator.
Field excitation can be obtained by the following meansPermanent magnetsField coils excited from some external source andField coils excited by the generator itself.
The excitation voltage can be produced by the generator itself or it can be supplied by an outside source, such as a battery.
If the flux is established using permanent magnets, then this type of dc generator is called Permanent magnet dc generator.
If the flux is obtained by exciting field coils from some external source, that type of dc generator is called Separately excited dc generator.
If field coils are excited by the generator itself to establish the required flux, then such type of dc generators are called Self-excited dc generators.
Generators are generally classified according to these methods of field excitation. On this basis, different types of dc generator are divided into the following three classes:Permanent magnet dc generators Separately excited dc generators Self-excited dc generators Series Wound dc generatorShunt Wound dc generatorCompound Wound dc generatorTypes of dc generator
In permanent magnet dc machines, a permanent magnet is used to establish flux in the magnetic circuit.
These generators are not found in industrial applications because of the low power generated from it. Such generators are employed only in small sizes like dynamos in motorcycles.
The behavior of a dc generator on load depends upon the method of field excitation adopted.Separately Excited D.C. Generators
A dc generator whose field magnet winding is supplied from an independent external d.c. source (e.g., a battery etc.) is called a separately excited generator.Seperately excited dc generator
The figure shows the connections of a separately excited generator. The voltage output depends upon the speed of rotation of armature and the field current (Eg = φZNP/60 A). The greater the speed and field current, the greater is the generated EMF of DC Generator.
It may be noted that separately excited DC generators are rarely used in practice. The DC generators are normally of self-excited type. Also, read characteristics of separately excited dc generator.
Armature current, Ia = IL
Terminal voltage, V = Eg – IaRa
Electric power developed = EgIa
Power delivered to load = EgIa – I R = I E – I R = VIa Self-Excited D.C. Generators
A d.c. generator whose field magnet winding is supplied current from the output of the generator itself is called a self-excited generator.
A generator that supplies its own field excitation is called a self-excited generator. Self-excitation is possible only if the field pole pieces have retained a slight amount of permanent magnetism, called residual magnetism.
When the generator starts rotating, the weak residual magnetism causes a small voltage to be generated in the armature. This small voltage applied to the field coils causes a small field current.
Although small, this field current strengthens the magnetic field and allows the armature to generate a higher voltage. The higher voltage increases the field strength, and so on. This process continues until the output voltage reaches the rated output of the generator.
There are three types of self-excited dc generator depending upon the manner in which the field winding is connected to the armature, namely;Series generatorShunt generatorCompound generator1. DC Series Generator
In a series-wound generator, the field winding is connected in series with armature winding so that whole armature current flows through the field winding as well as the load.
The figure shows the connections of a series-wound generator. Since the field winding carries the whole of load current, it has a few turns of thick wire having low resistance.
A series-wound DC generator characteristic shows that the output voltage varies with load current. This is undesirable in most applications. For this reason, this type of generator is rarely used in everyday practice.2. DC Shunt Generator
In a shunt generator, the field winding is connected in parallel with the armature winding so that the terminal voltage of the generator is applied across it.
The shunt field winding has many turns of fine wire having high resistance. Therefore, only a part of armature current flows through shunt field winding and the rest flows through the load. Also, read the characteristics of a shunt generator.
A combination of the two types can overcome the disadvantages of both. This combination of windings is called the compound wound DC generator.3. DC Compound Generator
In a compound-wound generator, there are two sets of field windings on each pole – one is in series and the other in parallel with the armature.
In the compound-wound generator when load current increases, the armature voltage decreases just as in the shunt-wound generator. This causes the voltage applied to the shunt-field winding to decrease, which results in a decrease in the magnetic field.
This same increase in load current, since it flows through the series winding, causes an increase in the magnetic field produced by that winding.
By proportioning the two fields so that the decrease in the shunt field is just compensated by the increase in the series field, the output voltage remains constant.
As you can see in compound wound generator characteristics, by proportioning the effects of the two fields (series and shunt), a compound wound generator provides a constant output voltage under varying load conditions.
The characteristics of DC compound generator refer to the relationship between various parameters that define the operational behavior of the generator.
DC compound generators have both series and shunt excitation are combined as shown in the figure. Their characteristics are different from series and shunt generator.DC Compound Generator
Based on the field winding connection a dc compound generator can be classified in to two types.
The shunt winding of DC compound generator has two possible connections:Short-shunt connection (S): connected across the armature only.Long-shunt connection (G): connected across both the armature and the series field.
The compound generator can be cumulatively compounded or differentially compounded generator. More about them is explained in types of DC Generator.
The differentially compounded generator is rarely used in practice. Therefore, we shall discuss the characteristics of a cumulatively compounded generator in this article.
It may be noted that the external characteristics of long and short shunt compound generators are almost identical.External characteristics of DC Compound Generator
The external characteristics of a cumulatively compounded generator are shown in the figure.External characteristics of DC Compound Generator
The series excitation aids the shunt excitation. The degree of compounding depends upon the increase in series excitation with the increase in load current.
If series winding turns are so adjusted that with the increase in load current the terminal voltage increases, it is called over-compounded generator.
In such a case, as the load current increases, the series field mmf increases and tends to increase the flux and hence the generated voltage.
The increase in generated voltage is greater than the IaRa drop so that instead of decreasing, the terminal voltage increases as shown by curve A.
If series winding turns are so adjusted that with the increase in load current, the terminal voltage substantially remains constant, it is called flat-compounded generator.
The series winding of such a machine has a lesser number of turns than the one in an over-compounded machine. Therefore, does not increase the flux as much for given load current. Consequently, the full-load voltage is nearly equal to the no-load voltage as indicated by curve B.
It has better voltage regulation compared to simple shunt generators.Under Compounded Generator
If the series field winding has a lesser number of turns than for a flat compounded machine, the terminal voltage falls with an increase in load current as indicated by curve C.
In this article, we will discuss different types of DC generators, their definition, features, and characteristics equations.
An electromechanical energy conversion device that converts mechanical energy into electrical energy is called a generator. Depending on the type of electricity produced, the electric generators are mainly classified into two types namely,AC GeneratorDC Generator
An electromechanical energy conversion device that converts rotational mechanical energy into electrical energy in the form of DC (Direct Current) is called a DC generator or direct current generator. Whereas, an electromechanical energy conversion device that converts mechanical energy into electrical energy in the form of alternating current (AC) is known as an AC generator or alternating current generator. In this article, we will limit our discussion to DC generators and their types only.
A type of DC generator in which the field winding to produces the magnetic field is excited from a separate (or external) source of DC supply is called a separately excited DC generator.
The circuit diagram of a typical separately excited DC generator is shown in the figure-1. It consists of a field winding that is supplied by a DC source like a battery through a variable resistor. The armature winding is directly connected across the load to which the generated electric power is supplied.
In practice, the magnitude of the generated voltage of separately excited generated is regulated in two ways:
Although, due to some technical and economical reasons, the separately excited DC generators are less popular these days.Important Relations Related to Separately Excited DC Generator
By referring to the circuit diagram (shown in figure-1), we can write the following characteristics equations of a separately excited DC generator.
(1). Armature current of the generator
i.e. in the case of a separately excited DC generator, the armature current and load current are the same.
(2). Terminal voltage of the generator
(3). Total electric power generated by the generator
(4). The power delivered to the load by the separately excited DC generatorSelf-Excited DC Generator
A type of DC generator in which the field winding is excited by a part of the power produced by the generator itself is called a self-excited DC generator. Therefore, it is one major advantage of a self-excited DC generator that it does not require any external source of power for the field winding excitation.
The self-excited DC generators are of three types according to the connection arrangement of field winding and armature winding.
A series DC generator is the one in which the field winding is connected in the series with the armature winding. The figure-2 shows a circuit diagram of a typical series DC generator.
From the figure, it is clear that the whole armature current flows through the series field winding and the load. Therefore, the field winding of a DC series generator is made with thick wire and few turns.
With the help of the circuit diagram of the series DC generator, we can write the important expression of a DC generator as follows:
(1). Armature current of the DC series generator is,
(2). Terminal voltage of the DC series generator is,
About Short shunt compound dc generator
As the photovoltaic (PV) industry continues to evolve, advancements in Short shunt compound dc generator have become critical to optimizing the utilization of renewable energy sources. From innovative battery technologies to intelligent energy management systems, these solutions are transforming the way we store and distribute solar-generated electricity.
When you're looking for the latest and most efficient Short shunt compound dc generator for your PV project, our website offers a comprehensive selection of cutting-edge products designed to meet your specific requirements. Whether you're a renewable energy developer, utility company, or commercial enterprise looking to reduce your carbon footprint, we have the solutions to help you harness the full potential of solar energy.
By interacting with our online customer service, you'll gain a deep understanding of the various Short shunt compound dc generator featured in our extensive catalog, such as high-efficiency storage batteries and intelligent energy management systems, and how they work together to provide a stable and reliable power supply for your PV projects.
