In today’s article, you will know what is a DC machine? And the description of the structure and main part of the DC machine. In this article, I am going to give information about all these in a very good way. so let’s start
what is a dc machine?
The structure of the DC generator and DC motor is the same. For this reason, we can use the machine as a generator.
From the point of view of the structure, there is no difference between the DC motor and the DC generator. The same DC machine can be used for both motor and generator. If the machine is connected to the power supply, the machine will act as a motor. will generate mechanical force and if the same machine is driven by the mechanical force of the first conductor, it will act as a generator and generate electric power.
- Read more: what is a DC generator?
Both the motor and the generator can be used in the same machine, but the motor is of a completely or partially closed structure for rough use, while the generator is made of an open structure for cooling.
In a DC machine, the field coils are on the stator. But in the DC machine, there is a separate structure for the two poles.
Structure of DC Machine
Main parts of DC machine
(1) Field magnet: pole core, pole shoe, and field winding
(2) Yoke, (3) Armature core
(4) Armature winding
The description of the parts of the DC machine is as follows
(1) Field magnet – There are three parts of field magnet, they are as follows
(i) Dhruv core
(ii) Dhruva Shoe
(iii) Kshetra Kundali
The pole core is made of iron and either soft steel laminated but for larger machines, both the pole core and the pole shoe are made of laminated steel. The shape of the rolled pole shoe is round and is near the armature. The pole core and the plated part of the pole shoe are on the surface on which the armature rotates. Dhruv Shu has two functions.
(a) providing the basis for magnetic coils
(b) To spread the flux symmetrically in the air space due to lowering of the magnetic circuit and higher cross-sectional area of the shoe.
The upper part of the field magnet is tightened with the yoke with the help of nut bolts. In that field magnet, the pole core and the lower part are called Shu. Inside it, a coil is made from insulated copper wires. To make the Kshetra Kundli, first the pole core. Form of shape is made. After that, with the help of form, field coils are made and trapped in the pole core.
(2) Yoke – This is the outer shell of the machine, which is round in shape. Yokes are made of cast iron or steel and rolled steel. The yoke of small machines is made of cast iron and the yoke of large machines is made of cast and rolled steel because it reduces the weight of the machine but the yoke of big machines is made in two parts.
are molded and both the parts are joined with the help of nut bolts. Then it mechanizes the pole of the machine and protects it from external damage. The pole core is attached to the yoke, due to which it has to be attached from the inside.
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(3) Armature core – The part of the machine that rotates is called an armature. The armature is made up of a driver. The armature core is made of circular plates of silicon steel about 6.35 mm (1/4 inch) thick of cylindrical shape, with slots cut around its circumference for inserting armature conductors or windings. Due to which the panels are dried with varnish or oxide coating and then with the help of a hydraulic press machine they are made into a cylindrical shape.
By making the panels thinner and coating them with a varnish or oxide layer, the resistance of the vortex current path increases, resulting in reduced vortex current loss. Large machines have air holes parallel to the axis of the armature core, which aids in armature cooling. The armature core mainly establishes its coil inside itself, due to which the armature core rotates in its magnetic field, then it provides a path of low resistance to the flux passing through it.
(4) Armature winding – Armature coil is made of enameled copper wire. These coils are first wrapped on the firm, after that, they are inserted into the slots of the armature made of copper wire. Before inserting the coil into the grooves of the armature, empire cloth made of copper wire and leatheroid paper is applied in the grooves, so that there is no damage to the insulation of the coil. After the coil is inserted, the wood of the grooves is closed with wedges and the ends of the coil are connected to the commutator.
(5) Commutator – This is the most important part of the DC machine which generates an alternating current in the armature. With that, we convert from alternating current to direct current with the help of a dynaconverter. It is cylindrical made of hard-drawn copper blocks having high conductivity.
These copper blocks are each insulated by mica and they are made of a ‘V’ shape so that they cannot fly away due to centrifugal force. These ‘V’ shaped grooves are insulated by rings of mecanite. There are lugs at the ends of the copper blocks to hold the conductors.
(6) Brush – Brush is made of carbon and copper in a rectangular shape. These bushes are placed in holders, which are called brush holders. These bushes look like a brush yoke on a stand. Brush gear consists of brush yoke, bush holder, and bush. The job of the brush is to collect the current from the converter and we pass it to the external circuit, by which this brush rotates the converter on the part where the bush is attached. Whatever the place of the brush is, we apply it from one brush to another with the help of segments. Due to this, whatever coil rotates, it rotates 90° from the line of flux. Due to this, the electric spark becomes very high and large machines can cause great damage to the spark converter.
Hence carbon brushes are used in larger machines. The resistance of carbon is higher than that of copper, which prevents fouling and also acts as a lubricant for the carbon brush convertor.
The brush is usually mounted in a box-type holder into which spring pressure is applied to maintain proper contact with the converter and the bush is connected to the holder of the external circuit by a pigtail connection.
(7) Bearing – Either a bearing ball or a bearing is used to attach to the armature shaft. Full lubricant is applied to drive the bearings. Bearings are usually made from gunmetal and baby metal.
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Now you must have known well what is a DC machine? and the structure of a DC machine and the description of the main parts of the DC machine, you must have got a good idea about all these.