Construction and Working Principle of DC Machine

Introduction

• A DC machine is an electromechanical energy conversion device.
• It can convert electrical energy into mechanical energy and vice versa.
• Two types of machines: DC generator and DC motor.

Construction

External and Internal Parts

• Stator (Static Part): Outer part, known as 'Yoke'.
  • Function of the yoke:
    • Provides mechanical strength.
    • Protects the internal assembly.
    • Provides a low reluctance path.
    • Generally made of cast iron or silicon steel.
• Rotor (Rotating Part): Inner part.

Poles

• Four magnetic poles with pole core and pole shoe.
  • Pole core: Cylindrical shape.
  • Pole shoe: Projected part, which makes the magnetic field uniform.
  • Made of silicon steel to reduce hysteresis and eddy current losses.

Armature

• Armature Core: Made from silicon steel laminated stampings.
  • Armature conductors are placed in slots.
• Commutator: Converts between DC and AC.
• Brushes: Made of carbon, for current collection.

Working Principle

DC Motor Operation

• Current flows through the DC motor from the DC supply.
• Field winding provides a magnetic field.
• Torque is generated in the armature conductor, causing the motor to rotate.

Commutator Function

• In motor: Converts DC supply to AC, causing rotation.
• In generator: AC is generated in armature conductor, which is converted to DC.

Conclusion

• The main components in the construction of a DC machine are the yoke, poles, armature core, commutator, and brushes.
• The main function of the yoke is to provide mechanical strength and a magnetic path.
• The function of the commutator is to maintain the current in the correct direction.

Note

• If you have any questions, feel free to ask in the comments section and like the video.