File Name: parts of dynamo and its functions .zip
- Construction of a DC Generator
- Generators & Dynamos
- Parts Of Ac Generator
- What is a DC Generator : Construction and Its Working
Construction of a DC Generator
The major advantages of dc machines are the easy speed and torque regulation. However, their application is limited to mills, mines and trains. As examples, trolleys and underground subway cars may use dc motors. However, the recent development of power electronics has reduced the use of dc motors and generators.
The electronically controlled ac drives are gradually replacing the dc motor drives in factories. Nevertheless, a large number of dc motors are still used by industry and several thousand are sold annually. The parts of a dynamo or related equipment can be expressed in either mechanical terms or electrical terms. Mechanical Rotor: The rotating part of an alternator, generator, dynamo or motor. Stator: The stationary part of an alternator, generator, dynamo or motor. Electrical Armature: The power-producing component of an alternator, generator, dynamo or motor.
The armature can be on either the rotor or the stator. Field: The magnetic field component of an alternator, generator, dynamo or motor. The field can be on either the rotor or the stator and can be either an electromagnet or a permanent magnet. A DC machine consists of the following essential parts 1. Magnetic frame or Yoke 2. Pole-cores and Pole-Shoes 3. Field Poles 4. Field Coils 5. Armature Core 6. Armature Windings or Conductors 7. Commutator 8. Brushes and Bearings.
Yoke Yoke is the outer frame. It serves two purposes. Pole Cores and Pole Shoes The field magnet consist of pole cores and pole shoes.
They have two purposes: i they spread out the flux in the air gap and also, being larger cross section, reduce the reluctance of the magnetic path ii they support the exciting coils field coils.
The pole cores can be made from solid steel castings or from thin laminations of highly magnetic steel alloy. Field Coils The field coils are those windings, which are located on the poles and set up the magnetic fields in the machine. They also usually consist of copper wire are insulated from the poles. The field coils may be either shunt windings in parallel with the armature winding or series windings in series with the armature winding or a combination of both.
Armature Core The armature core is made up thin magnetic steel laminations stamped from sheet steel with a blanking die. Slots are punched in the lamination with a slot die. The laminations are welded, riveted, bolted or bonded together. It houses the armature conductors or coils, and causes them to rotate and hence cut the magnetic flux of the field magnets.
Air Gap The space between the armature and the pole shoes. Armature Winding The armature winding fits in the armature slots and is eventually connected to the commutator. It either generates or receives the voltage depending on whether the unit is a generator or motor. The armature winding usually consists of copper wire, either round or rectangular and is insulated from the armature stack.
Gramme -Ring armature The old Gramme-Ring armature, now obselete is shown below. A drum-type armature is shown in figure. The armature windings are placed in slots cut in a drum-shaped iron core.
In drum-type armature: each winding completely surrounds the core so that the entire length of the conductor cuts the main magnetic field. Therefore, the total voltage induced in the armature is greater than in the Gramme-ring. The drum-type armature is much more efficient than the Gramme-ring. This accounts for the almost universal use of the drum-type armature in modern dc generators.
Commutator The commutator is the mechanical rectifier, which changes the AC voltage of the rotating conductors to DC voltage. It consists of a number of segments normally equal to the number of slots.
The segments or commutator bars are made of silver bearing copper and are separated from each other by mica insulation. Brushes The brushes, whose function is to collect current from commutator, are usually made of carbon or graphite and are in the shape of a rectangular block.
These brushes are housed in brush-holders usually of the box type variety. The periphery of the armature divided by the number of poles of the generator; the distance between two adjacent poles It is equal to the number of armature conductors per pole. Radial length of the pole face measured in inches, cm. Slot pitch or Slot span Sp. This is the distance from the center of one slot to the center of an adjacent slot, measured on the surface of the armature.
Conductor The length of a wire lying in the magnetic field and in which an e. Coil and Winding Element With reference to the figure, the two conductors AB and CD along with their end connections constitute one coil of the armature winding.
The coil may be single turn or multi-turn coil. A single turn coil wil have two conductors. But a multi-turn coil may have many conductors per coil side. Coil-span or Coil-pitch It is the distance, measured in terms of armature slots, between two sides of a coil. It is, in fact, the periphery of the armature spanned by the two sides of the coil.
If the coil-pitch is equal to the pole-pitch,then winding is called full-pitched. It means that coil span is electrical degrees. If the coil-pitch is less than the pole-pitch, then the winding is fractional-pitched. Back Pitch YB The distance, measured in terms of the armature conductors, which a coil advances on the back of the armature is called back pitch. Commutator Pitch YC It is the distance between the segments to which the two ends of a coil are connected.
Two types of windings: 1. Lap Winding - This type of winding is used in dc generators designed for high-current applications 2. Wave Winding - This type of winding is used in dc generators employed in high-voltage applications.
The difference between the two is merely due to the different arrangement of the end connections at the front or commutator end of armature. Each winding can be arranged progressively or retrogressively, and connected in simplex, duplex and triplex. In simplex lap winding, the ends of each coil are connected to adjacent commutator segments.
In this way, all the coils are connected in series. In a duplex lap winding, there are in effect two separate sets of coils, each set connected in series. Similarly, in a triplex lap winding, there are in effect three separate sets of series-connected coils.
In a wave winding, the ends of each coil are connected to commutator segments two pole spans apart. If, after passing once round the armature, the winding falls in a slot to the left of its starting point then winding is said to be retrogressive. If, however, it falls one slot to the right, then it is progressive.
A conductor of active length 30 cm carries a current of A and lies at right angles to a magnetic field of strength 0. If the force causes the conductor on problem no. Find the induced emf of an 8-pole, wave-wound dynamo having 4mWb per pole and rotating at rpm. The armature has slots, and there are 3 coils per slot, each having 2 turns. Open navigation menu. Close suggestions Search Search. User Settings. Skip carousel. Carousel Previous. Carousel Next. What is Scribd? Dynamo Parts.
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Generators & Dynamos
Dynamos and Generators convert mechanical rotation into electric power. Dynamo - a device that makes direct current electric power using electromagnetism. It is also known as a generator, however the term generator normally refers to an "alternator" which creates alternating current power. Generator - normally this term is used to describe an alternator which creates AC power using electromagnetism. Batteries may have been discovered as early as BC.
Parts Of Ac Generator
A dc generator is an electrical machine which converts mechanical energy into direct current electricity. This energy conversion is based on the principle of production of dynamically induced emf. This article outlines basic construction and working of a DC generator.
A dynamo is an electrical generator that creates direct current using a commutator. Dynamos were the first electrical generators capable of delivering power for industry, and the foundation upon which many other later electric-power conversion devices were based, including the electric motor , the alternating-current alternator , and the rotary converter. Today, the simpler alternator dominates large scale power generation , for efficiency, reliability and cost reasons. A dynamo has the disadvantages of a mechanical commutator. Also, converting alternating to direct current using rectifiers such as vacuum tubes or more recently via solid state technology is effective and usually economical.
What is a DC Generator : Construction and Its Working
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. An electric generator is a device that converts mechanical energy obtained from an external source into electrical energy as the output.
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.
Dynamo. Not to be confused with dynamometer. For other uses, see Dynamo (disambiguation). A dynamo is an as a power supply, the word dynamo became associated exclusively ery: a manual for students of electrotechnics. London: E.