Dc Generators Pdf

If the loop rotates further, it comes to again in a horizontal position. The terminal voltage of series generator increases with load current from no load to full load. Circuit Globe All about Electrical and Electronics. As the loop gets closed there will be a current circulating through the loop. The rotating parts like armature core, commutator, cooling fans, etc.

Dc generator.pdf download

It works based on principle of the electromagnetic induction. The outer hollow cylindrical frame to which main poles and inter-poles are fixed and by means of which the machine is fixed to the foundation is known as Yoke. Carbon brushes are placed or mounted on the commutator and with the help of two or more carbon brushes current is collected from the armature winding.

These generators are packaged with an engine or turbine to be used as a motor-generator set and used in applications like naval, oil and gas extraction, mining machinery, wind power plants etc. The shaft is made of mild steel with a maximum breaking strength. This impressed voltage builds up stronger winding current, raises the strength of the magnetic field. The shunt field winding has many turns of fine wire having high resistance. Magnetic field system, Armature and Commutator and Brush gear.

In this case number of brushes is equal to two, i. Rotating field type of alternator is widely used because of high power generation capability and absence of slip rings and brushes.

Your email address will not be published. Series generators are rarely used except for special purposes e. These are of two types one is induction generator and other one is synchronous generator. For electro plating Battery charging For excitation of Alternators. Features, Components and Classification.

Some of this voltage is making on the field windings through the generator regulator. Over compound generators are used to compensate the voltage drop in Feeders. The front housings support the bearing and the brush assemblies where as the rear housings usually support the bearings only. The brushes are pressed upon the commutator and form the connecting link between the armature winding and the external circuit. Therefore, only a part of armature current flows through shunt field winding and the rest flows through the load.

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Voltage Regulation of Transformer. Mostly high carbon steel is used for the construction of bearings as it is very hard material.

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The commutator, which rotates with the armature, is cylindrical in shape and is made from a number of wedge-shaped hard drawn copper bars or segments insulated from each other and from the shaft. Each commutator segment is connected to the ends of the armature coils.

Characteristics of 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. In Wye Connection one end of each coil connected together and the other end of each coil left open for external connections. This concept takes place when conductor coils turn in a magnetic field actuating a current and a voltage. Please go through the construction of dc generator before reading this topic.

Now if we apply this right-hand rule, we will see at this horizontal position of the loop, current will flow from point A to B and on the other side of the loop current will flow from point C to D. When the loop rotates from its vertical position to its horizontal position, it cuts the flux lines of the field.

Now the loop is opened and connected it with a split ring as shown in the figure below. In cumulative wound generators the series field assists the shunt field, whereas, in differential wound generators, series field opposes the shunt field. Transformer on No Load and Load.

For any assistance please email us on team elprocus. Such generators are employed only in small sizes like dynamos in motorcycles. The function of the bearings is to reduce friction between the rotating and stationary parts of the machine. In the next half revolution, in the figure, the direction of the induced current in the coil is reversed.

Dc generator.pdf download

Armature winding is a place where conversion of power takes place. The rotating armature cuts the magnetic field, due to which an emf is induced in it.

Each lamination is insulated from the other by a coating of varnish. On the basis of connections, the windings are classified into two types named as Lap Winding and Wave Winding. In permanent magnet dc machines, a permanent magnet is used to establish flux in the magnetic circuit. These are used in electro plating and electro refining applications. These are used for low power output applications.

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 point when the generator armature first starts to turn, then there is a weak magnetic field in the iron pole shoes. If we observe this phenomenon differently, we can conclude, that each side of the loop comes in front of N pole, the current will flow through that side in the same direction, i.

Generators are generally classified according to these methods of field excitation. These generators are not found in industrial applications because of the low power generated from it. Differential Compound generators are used to supply dc welding machines. Since the poles, basic programming in c pdf project inwards they are called salient poles. These may be rotating field type or rotating armature type.

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The Pole Core and Pole Shoes are fixed to the magnetic frame or yoke by bolts. We connect the external load terminals with two carbon brushes which rest on these split slip ring segments. The mmf necessary to establish flux in the magnetic circuit of a dc generator can be obtained by means of. These can be connected either delta or wye connections.

In wave winding, the conductors are so connected that they are divided into two parallel paths irrespective of the number of poles of the machine. Equivalent Circuit of Transformer. In Delta Connection each coil end is connected together to form a closed loop. Level compound generators are used to supply power for offices, hostels and Lodges etc. This current is unidirectional.

Now if the loop is continued to rotate about its axis. Also, read characteristics of separately excited dc generator. With the help of the brushes the current which is produced on the windings, is passed on to the commutator and then to the external circuit.

Single Loop DC Generator