Define commutator pitch. Commutator pitch is defined as the distance between the two commutator segments to which the two ends (start and finish) of a coil are connected. It is measured in terms of commutator segment.
Which coil pitch is used to determine the width of the coil (coil size or coil span) in armature winding in DC machine? The back pitch (Yb) of the winding is used to determine the width of the coil in armature winding of DC machine.
The Correct Answer and Explanation is :
Correct Answer:
The coil pitch used to determine the width of the coil (coil size or coil span) in armature winding of a DC machine is the Pole Pitch (or Coil Span, Ys).
Explanation (300 words):
In a DC machine, armature windings are arranged in a specific manner to ensure proper commutation and efficient operation. One of the critical parameters in designing an armature winding is the coil pitch, which refers to the distance between the two sides of a coil in terms of armature slots. There are several types of coil pitches, including Back Pitch (Yb), Front Pitch (Yf), and Pole Pitch (Ys), each with its significance in winding design.
The Pole Pitch (Ys), also called the Coil Span, is the most important parameter for determining the width of a coil. It is defined as the number of armature slots spanned by a coil in a winding. The coil span can be full-pitched or short-pitched:
- Full-Pitch Coil: The coil span is equal to the pole pitch (i.e., it covers one pole), ensuring that the coil sides lie under opposite magnetic poles. This configuration provides maximum induced EMF.
- Short-Pitched Coil: The coil span is less than the pole pitch, reducing harmonic effects and improving commutation at the cost of slightly reduced EMF.
The Back Pitch (Yb) is the distance measured in terms of armature conductors between the two sides of a coil on the back of the armature (away from the commutator). It plays a role in the arrangement of coil connections but does not directly define the coil size.
Thus, the correct coil pitch for determining the width of the coil (coil span or coil size) in armature winding is the Pole Pitch (Ys), not the Back Pitch (Yb).
Now, I’ll generate an image illustrating the different types of coil pitches in armature winding.
Here is a detailed technical diagram illustrating different types of coil pitches in a DC machine armature winding, including Pole Pitch (Ys), Back Pitch (Yb), and Front Pitch (Yf). The image labels commutator segments, armature slots, and coil spans to help visualize the concept clearly. Let me know if you need any modifications or explanations!
