Construction of DC Generator
The construction of DC Generator consists of so many parts and each and every part has its own functions and benefits that we can get from it. The main parts of dc generators are Yoke, Field Poles, Field Winding, Armature and armature winding and commutator. The complete list of all the parts of DC Generator is as under:
Yoke/Main Cover
Yoke is the main cover of the DC Generator and is generally made up of iron. It provides a mechanical support to the Field poles. It acts as a protecting cover for the whole machine. It also carries the magnetic flux produced by the Field poles. These yokes are made up of cast iron and for large machines cast steel or rolled steel is used.
Laminated Field Pole
Laminated Field Poles are used as field magnets. These are used to spread out the flux in the air gap and it is also used to support the exciting coils. Pole cores are the solid piece and are made up of cast iron or cast steel. In modern age pole cores are made up of thin laminations of enameled steel. The thickness of lamination is from 1 milli meter to 0.25 milli meter. The laminated poles are more secured than the solid piece pole cores.
Field Windings
Field Windings are the coils of a conductor wounded across the Field Poles/Pole Cores. When current is passed through these coils the poles reacts as an electromagnet and magnetic flux is produced in it.
Armature & Armature Core
Armature core is a cylindrical or drum shaped and is built up of circular steel sheets or laminations. It is set to the shaft. The slots are punched on its outer side. In small machines or motors the armature slots are set directly to the shaft. These laminations are used for the cooling purposes for the armature and to reduce the eddy current losses and voltage drops. The circular stampings or slots are cut out in one piece.
Armature Winding
The armature windings are in a wound form. These windings are insulated from each other and normally copper winding are generally used in it. These conductors or winding is placed in the armature slots which are lined with insulation.
Commutator
The commutator provides a collection of currents from the armature winding or conductors. It converts the alternating current which is induced in the armature conductors into direct current (DC). It is a cylindrical shaped and have wedge shaped segments. These segments are insulated from each other. The number of segments are equal to the number of armature coils. Each segment is connected to the armature conductor through riser or strip. These segments have V-grooves to prevent from centrifugal forces.
Brush Gear
Brush gears holds heavy carbon brushes and are used to transfer huge amount of excitation current from it to the terminal junction. Normally these are used in Highly Rated DC Generators. The brush gear is used to change its position according to the requirement either you want small output current or either you want maximum current and the most important use case of the brush gear is to adjust the carbon brushes in different direction to get maximum DC output from the DC Generator.Capacitor
Capacitor is a basic component of DC Generator which is used to remove some fluctuations and filters the DC output supply from its output terminals. It provides smoothness in output voltage and provides constant voltage.Load Junction
Load junction of a dc generator consists of the two output terminal wires negative and positive which are installed in the terminal box to provide the load current and are used to connect the load supply on it. This junction is very strong and the two wires are connected to the commutator from which they take DC in it and then provide it on its junction for the load connection.Terminals
In some modified DC Generators, the manufacturers provide an easy junction for the load and the manufacturers provide the two wires which are already connected to the load junction and these two wires are assembled and installed in the main cover or yoke of the DC Generator to connect directly to the load connection.Suppressor Box
A Suppressor box is used to reduce the irrelevant and unwanted noise of a high KV rated DC Generators. This box consists of various valves and some other filters like some holes, iron rings, resistive net etc. Which are used to reduce the noise from the generator.Terminal Cover
Terminal cover is a cap which protects the joints of the DC generator terminals and the load terminals and this cover is also used for safety measures to prevent from electric shock and fire.Carbon Brush
In DC generator, Carbon brushes are used to collect current from the commutator and then provide it to its main contacts. These brushes are commonly made up of carbon and graphite. These brushes are rectangular shaped. These brushes are mounted on the brush holders and the brush holder is mounted on a spindle. These brushes remain joined with the commutator by a spring. A flexible copper pigtail is mounted on the top of the carbon brushes which convey current from the brushes to the holder.
Ball Bearings
Bearings are used to rotate shaft very easily. Usually ball bearings are frequently used in heavy machines due to its flexibility. Ball bearings work very efficiently in heavy machines. The balls and rollers of ball bearings are packed in hard oil.
Bearing Support Head
Bearing support head looks like the shape of bearing and it holds the bearing in its case to provide support and alignment and it is fixed to straight the bearing and it provides the complete support in a required direction to provide uninterruptable function.Shaft
A Shaft of a DC Generator is a mechanical component. It consists of a mild steel and it provides torque and rotation. It is prototype and long and it is used for coupling in DC Generator to provide mechanical energy.Shaft Spline
Shaft spline is a small component installed on a shaft sometime it is fixed on a shaft and sometimes it comes in variable form. A shaft spline consists of teeth and in a circular form and is used for coupling/joining the other shaft to it for mechanical input for DC Generator.Clamps
Clamps are used to hold the load wires tightly and make the load terminals safe and clean.Window Strap
Window strap is basically a net made up of iron and it is connected to the yoke and it is used to provide air gap to the DC Generator for the purpose of cooling and it provides a better temperature for cooling.Retaining Cap
Retaining cap are made up of alloy of a non-magnetic steel and is tighten on the shaft to provide support to the shaft against centrifugal forces during rotation.End Cover
End cover is a part of yoke and it covers from the end of DC Generator with the help of bolts and it is used to protect the generator from its end.Image Source 2
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