Chapter 2 - Commutation & DC Motor Construction

Question 1

Main parts in Motor Construction?

Answer 1

1. Rotor made up of the Laminated Iron Core consisting of the Armature windings.
2. Stator made up of the Yoke, Field Windings, and Brush Gear.
3. The Commutator.

Question 2

Armature Windings construction?

Answer 2

Armature windings consist of all the armature conductors wound into a coil which span the armature.

The end of all armature wound coils terminate at the commutator segment.

Question 3

Construction of the Laminated Iron Core?

Answer 3

The Laminated Iron Core holds the armature winding in slots around its circumference. It also forms part of the magnetic circuit It is laminated to reduce Eddy Current.

Question 4

Construction of the Commutator?

Answer 4

Made up of copper segments. These segments are insulated from one another an form the shaft.

The commutator ensures current flows in the same direction through the armature winding as they rotate around 360 degrees this ensure force/motion is kept in the same direction.

Question 5

Construction of the Yoke?

Answer 5

Made from steel it forms the body of the machine. Because it’s made from a ferromagnetic material it ensures the return path of the magnetic circuit.

Question 6

Construction of the Field System/Winding?

Answer 6

Consists of an even number of electromagnets. The pole pieces are made from laminated Iron and attached to the Yoke this in turn forms the core of the electromagnets. The Field Winding’s are wound around the Pole Pieces

Question 7

Construction of the Brush Gear

Answer 7

consists of brush holders which the carbon brushes slide into (connected via a stranded copper wire pigtail) and are held at the correct angle to the commutator.the brushes are pressed against the commutator with the aid of an adjustable spring.