Question

In DC machines, the distance between two adjacent poles can be defined as:

1. pole size
2. armature length
3. pole-pitch
4. coil length

Answer 1

Correct Answer - Option 3 : pole-pitch

Pole pitch:

• It is defined as the peripheral distance between centers of two adjacent poles in the DC machine.
• This distance is measured in terms of armature slots or armature conductors come between two adjacent pole centers.
• A pole pitch in the electrical machine is equal to 180° electrical.
• This is naturally equal to the total number of armature slots divided by the number of poles in the machine. 
• ∴ Pole Pitch = (Number of armature slots) / (Number of poles)

 

Front pitch: The distance between the last side of the first coil and the first side of the second coil is called the front pitch.

Back pitch: The distance between the two sides of a coil in the back of the armature is called back pitch.

Coil pitch: The distance measured in terms of armature slots or armature conductors between two sides of a coil.