explain the different part of DC machine the diagram?
Answers
Answer:
Main parts of DC machines are
1) Yoke or Frame or Magnetic frame
2) Poles and Pole shoe
3) Armature
4) Armature winding and Field winding
5) Commutator
6) Brushes
7) Shaft
Step-by-step explanation:
1) Yoke:
The yoke make by cast steel for large machines and cast iron for a small machine. It uses to protect the internal parts of the DC machine and gives mechanical support to the poles. The yoke provides a return path for magnetic flux. In the yoke, the laminations are not required, but the modern machines uses the laminations in yoke.
2) Poles and Pole shoe:
The pole core use to provide housing to the field winding. When field winding excites, it behaves like a magnet. The pole shoes provide mechanical support to the field winding and due to a large area, it reduces the magnetic reluctance. The pole and pole shoe make by cast steel. Pole is not necessary to laminate. The pole shoe is always laminated because it is close to the armature.
3) Armature:
Armature core provides housing to the armature winding. It completes low reluctance path for magnetic flux. The armature slots are skew at some angle to reduce the mechanical vibration. Armature core is made with silicon steel. It is laminated to reduce the eddy current losses. In a DC machine, open slots are use to reduce leakage flux, inductance, and leakage reluctance.
4) Armature winding and Field winding:
There are two types of armature windings; Lap winding and Wave winding.
Lap winding is known as complete winding because, after completion of winding, all slots does fill with armature winding. Wave winding is known as incomplete winding because, after completion of winding, all slots does not fill with armature winding. Some slots remain empty. These slots do fill with dummy coils. The dummy coils only use in wave winding to fill empty slots and give mechanical balance. It is not used in lap winding.
In lap winding, due to unbalance flux and unbalance voltage, the circulating current is more. It causes more copper loss and heat. The circulating current can minimise by using the equalizer ring. In wave winding, circulating current does not exist.
The field winding connects with DC supply. Whenever the field winding is energies, it produces the magnetic flux and poles behaves like a magnet.
5) Commutator:
In case of a generator, the commutator uses to convert AC voltage into DC voltage. The commutator uses as a rectifier. In the case of the motor, the commutator use to produce unidirectional torque. To reduce wear and tear, the commutator make by hard drawn copper. The number of armature slots is equal to the number of commutator segments.
6) Brush:
Brushes use to carry the current or give the current to the armature conductors through the commutator. The brushes make by copper or carbon materials for small machines. Electro-graphite brushes use for large machines. Carbon-graphite brushes use for large current low voltage machines.
7) Shaft:
The shaft use to transfer mechanical power. In case of DC motor, mechanical power is transfer from DC machine to load. In the case of a DC generator, mechanical power is transfer from Prime mover to the DC generator.
Answer:
- The mene of DC is (directe current).
