Wave Winding MCQ Quiz - Objective Question with Answer for Wave Winding - Download Free PDF

Explanation:

The Number of Parallel Paths in a P Pole N-Plex Wave Winding

Definition: Wave winding is a type of winding used in electrical machines, particularly in armatures of DC machines. It is named "wave winding" because the winding progresses in a wave-like fashion across the surface of the armature. The number of parallel paths in such windings is a critical parameter that determines the current-carrying capacity and efficiency of the machine.

Key Formula for Wave Winding:

The number of parallel paths (A) in a wave winding is given by the formula:

A = 2

This means that, irrespective of the number of poles (P) or the plexity (n), the wave winding always results in only two parallel paths. This is a key characteristic of wave winding.

Explanation of the Correct Option:

The correct answer is:

Option 4: 2

This option is correct because, in wave winding, the number of parallel paths remains constant at 2, regardless of the machine's number of poles (P) or the plexity (n). This is because the winding is designed in such a way that it connects all the coils in series to form two parallel paths. These two paths carry the entire armature current, thereby ensuring efficient current distribution in the machine.

Additional Information

To further understand the analysis, let’s evaluate the other options:

Option 1: nP

This option suggests that the number of parallel paths is equal to the product of the plexity (n) and the number of poles (P). This is incorrect for wave winding. While this formula might apply to lap windings, where the number of parallel paths equals the number of poles multiplied by the plexity, it does not apply to wave winding. In wave winding, the number of parallel paths is always 2, irrespective of the values of n and P.

Option 2: P

This option implies that the number of parallel paths is equal to the number of poles (P). This is also incorrect for wave winding. While this might hold true for simplex lap windings, where the number of parallel paths equals the number of poles, wave winding always has only 2 parallel paths, regardless of the number of poles.

Option 3: 2

This option is the correct answer, as explained above. It accurately represents the number of parallel paths in wave winding, which is always 2.

Option 4: 2n

This option suggests that the number of parallel paths is twice the plexity (2n). While this might apply to lap windings with multiple plexities, it is not correct for wave winding. In wave winding, the number of parallel paths remains constant at 2, regardless of the plexity.

Conclusion:

Wave winding is characterized by its simplicity and efficiency, with the number of parallel paths fixed at 2. This feature makes it suitable for applications requiring higher voltage and lower current. By understanding the fundamental principle that wave windings always have two parallel paths, it becomes easier to distinguish them from other types of windings, such as lap windings, where the number of parallel paths depends on the number of poles and plexity.

Concept:

• The wave winding can be defined as the loop of the winding that can form the signal shape.
• The no of parallel paths is equal to two. The emf of wave winding is more. The efficiency of the wave winding is high.
• In wave winding, the number of parallel paths is two This winding is mainly used for high voltage and low current applications
• Lap winding: In lap winding, the number of parallel paths (A) is the same as the number of brushes and poles This winding is mainly used for low voltage and high current applications

A wave wound armature is a type of armature winding in which the coils are connected in series and follow each other on the surface of the armature like waves. This type of winding has two parallel paths, so only two brushes are required to collect current from the commutator.

Concept:

The armature winding of the DC machine is classified into two types:

1) Lap winding: 

• A = P
• (I_a)_L =  A(I_P)

2) Wave winding: 

• A = 2
• (Ia)w = 2(IP)

where A= No. of parallel paths

P= No. of poles

A= No. of parallel paths

(Ia)_L  = Armature current in Lap winding

(Ia)_w = Armature current in Wave winding

 I_P = Current in parallel path

 Calculation:

Given, For Lap winding : 

• A = P = 6 
• (Ia)L =  A(IP)

Given, For Wave winding : 

• A = 2
• (Ia)w = 2(IP)

By the power conservation theorem, total power remains constant irrespective of the connection type of the armature resistance.

 (P)_L = (P)_W

(Ia)2_L (Ra)_L = (Ia)2w  (Ra)_w

(6I_P)² (0.05) = (2IP)2 (Ra)w

(Ra)w = 9 × 0.05

(Ra)w = 0.45Ω

Dummy coils (Forced Winding):

• Wave winding is actually called incomplete winding because after completion of winding some slots are left empty.
• These empty slots are generally filled with some extra coils namely called dummy coils.
• These dummy coils are used for providing mechanical balance for the rotor only.
• Dummy coils are similar to other coils and are insulated from other coils.
• They physically exist but are not electrically connected.

Dummy coils exist in only wave winding but not in lap winding.

Mistake Points

Here question has a concern with the other name of dummy coils, hence the correct answer is forced winding.

If the question will have a concern with the application of dummy coil then our answer will be wave winding.

Armature winding of DC machine:

Modern dc machines employ two general types winding

1. Lap winding
2. Wave winding 

In the wave winding, the end of one coil is connected to the starting of another coil of the same polarity as that of the first coil.

• Back pitch YB the distance between the top and bottom coil sides of a coil measured around the back of armature is called back pitch.
• Front pitch YF the distance between the two coil sides connected to the same commutator segment is called front pitch.
• Winding or resultant pitch YR the distance between the starts of the two consecutive coils measured in terms of coil sides is called resultant pitch.
• Commutator pitch YC the distance between the two commutator segments to which the two ends of a coil are connected is called commutator pitch.
• In wave winding back pitch and front pitch, both are odd and are of the same sign.
• Back pitch and front pitch are nearly equal to pole pitch and maybe equal or differ by ± 2, + for progressive winding, - for retrogressive winding.
• Resultant pitch YR = YB + YF.
• Commutator pitch = average pitch = (YB + YF) / 2.

The armature winding of dc machine:

Modern dc machines employ two general types winding

1. Lap winding
2. Wave winding 

The most commonly used windings are simplex lap and wave windings.

Simplex wave winding:

• In this winding, we connect the end of one coil to the starting of another coil of the same polarity as that of the first coil.
• In this type of winding the coil, side progresses forward around the armature to another coil side and goes on successively passing through N and S pole till it returns to a conductor lying under the starting pole.
• This winding forms a wave with its coil, that’s why we call it as wave winding.

​

Important points:

• Back pitch Y_B the distance between the top and bottom coil sides of a coil measured around the back of armature is called back pitch.
• Front pitch Y_F the distance between the two coil sides connected to the same commutator segment is called front pitch.
• Winding or resultant pitch Y_R the distance between the starts of the two consecutive coils measured in terms of coil sides is called resultant pitch.
• Commutator pitch Y_C the distance between the two commutator segments to which the two ends of a coil are connected is called commutator pitch.
• In simplex wave winding back pitch and front pitch, both are odd and are of the same sign.
• Back pitch and front pitch are nearly equal to pole pitch and may be equal or differ by ± 2, + for progressive winding, - for retrogressive winding.
• Resultant pitch Y_R = Y_B + Y_F.
• Commutator pitch = average pitch = (YB + Y_F) / 2.

Concept:

The armature winding of the DC machine is classified into two types:

1) Lap winding: 

• A = P
• (I_a)_L =  A(I_P)

2) Wave winding: 

• A = 2
• (Ia)w = 2(IP)

where A= No. of parallel paths

P= No. of poles

A= No. of parallel paths

(Ia)_L  = Armature current in Lap winding

(Ia)_w = Armature current in Wave winding

 I_P = Current in parallel path

 Calculation:

Given, For Lap winding : 

• A = P = 6 
• (Ia)L =  A(IP)

Given, For Wave winding : 

• A = 2
• (Ia)w = 2(IP)

By the power conservation theorem, total power remains constant irrespective of the connection type of the armature resistance.

 (P)_L = (P)_W

(Ia)2_L (Ra)_L = (Ia)2w  (Ra)_w

(6I_P)² (0.05) = (2IP)2 (Ra)w

(Ra)w = 9 × 0.05

(Ra)w = 0.45Ω

Dummy coils (Forced Winding):

• Wave winding is actually called incomplete winding because after completion of winding some slots are left empty.
• These empty slots are generally filled with some extra coils namely called dummy coils.
• These dummy coils are used for providing mechanical balance for the rotor only.
• Dummy coils are similar to other coils and are insulated from other coils.
• They physically exist but are not electrically connected.

Dummy coils exist in only wave winding but not in lap winding.

Mistake Points

Here question has a concern with the other name of dummy coils, hence the correct answer is forced winding.

If the question will have a concern with the application of dummy coil then our answer will be wave winding.

Armature winding of dc machine:

Modern dc machines employ two general types winding

1. Lap winding
2. Wave winding 

In the wave winding, the end of one coil is connected to the starting of another coil of the same polarity as that of the first coil.

Important Points

• Back pitch YB the distance between the top and bottom coil sides of a coil measured around the back of armature is called back pitch.
• Front pitch YF the distance between the two coil sides connected to the same commutator segment is called front pitch.
• Winding or resultant pitch YR the distance between the starts of the two consecutive coils measured in terms of coil sides is called resultant pitch.
• Commutator pitch Y_C the distance between the two commutator segments to which the two ends of a coil are connected is called commutator pitch.
• In wave winding back pitch and front pitch, both are odd and are of the same sign.
• Back pitch and front pitch are nearly equal to pole pitch and maybe equal or differ by ± 2, + for progressive winding, - for retrogressive winding.
• Resultant pitch YR = YB + YF.
• Commutator pitch = average pitch = (YB + YF) / 2.

Concept:

• The wave winding can be defined as the loop of the winding that can form the signal shape.
• The no of parallel paths is equal to two. The emf of wave winding is more. The efficiency of the wave winding is high.
• In wave winding, the number of parallel paths is two This winding is mainly used for high voltage and low current applications
• Lap winding: In lap winding, the number of parallel paths (A) is the same as the number of brushes and poles This winding is mainly used for low voltage and high current applications

Armature winding of DC machine:

Modern dc machines employ two general types winding

1. Lap winding
2. Wave winding 

In the wave winding, the end of one coil is connected to the starting of another coil of the same polarity as that of the first coil.

• Back pitch YB the distance between the top and bottom coil sides of a coil measured around the back of armature is called back pitch.
• Front pitch YF the distance between the two coil sides connected to the same commutator segment is called front pitch.
• Winding or resultant pitch YR the distance between the starts of the two consecutive coils measured in terms of coil sides is called resultant pitch.
• Commutator pitch YC the distance between the two commutator segments to which the two ends of a coil are connected is called commutator pitch.
• In wave winding back pitch and front pitch, both are odd and are of the same sign.
• Back pitch and front pitch are nearly equal to pole pitch and maybe equal or differ by ± 2, + for progressive winding, - for retrogressive winding.
• Resultant pitch YR = YB + YF.
• Commutator pitch = average pitch = (YB + YF) / 2.

The armature winding of dc machine:

Modern dc machines employ two general types winding

1. Lap winding
2. Wave winding 

The most commonly used windings are simplex lap and wave windings.

Simplex wave winding:

• In this winding, we connect the end of one coil to the starting of another coil of the same polarity as that of the first coil.
• In this type of winding the coil, side progresses forward around the armature to another coil side and goes on successively passing through N and S pole till it returns to a conductor lying under the starting pole.
• This winding forms a wave with its coil, that’s why we call it as wave winding.

​

Important points:

• Back pitch Y_B the distance between the top and bottom coil sides of a coil measured around the back of armature is called back pitch.
• Front pitch Y_F the distance between the two coil sides connected to the same commutator segment is called front pitch.
• Winding or resultant pitch Y_R the distance between the starts of the two consecutive coils measured in terms of coil sides is called resultant pitch.
• Commutator pitch Y_C the distance between the two commutator segments to which the two ends of a coil are connected is called commutator pitch.
• In simplex wave winding back pitch and front pitch, both are odd and are of the same sign.
• Back pitch and front pitch are nearly equal to pole pitch and may be equal or differ by ± 2, + for progressive winding, - for retrogressive winding.
• Resultant pitch Y_R = Y_B + Y_F.
• Commutator pitch = average pitch = (YB + Y_F) / 2.

Concept:

The armature winding of the DC machine is classified into two types:

1) Lap winding: 

• A = P
• (I_a)_L =  A(I_P)

2) Wave winding: 

• A = 2
• (Ia)w = 2(IP)

where A= No. of parallel paths

P= No. of poles

A= No. of parallel paths

(Ia)_L  = Armature current in Lap winding

(Ia)_w = Armature current in Wave winding

 I_P = Current in parallel path

 Calculation:

Given, For Lap winding : 

• A = P = 6 
• (Ia)L =  A(IP)

Given, For Wave winding : 

• A = 2
• (Ia)w = 2(IP)

By the power conservation theorem, total power remains constant irrespective of the connection type of the armature resistance.

 (P)_L = (P)_W

(Ia)2_L (Ra)_L = (Ia)2w  (Ra)_w

(6I_P)² (0.05) = (2IP)2 (Ra)w

(Ra)w = 9 × 0.05

(Ra)w = 0.45Ω

Dummy coils (Forced Winding):

• Wave winding is actually called incomplete winding because after completion of winding some slots are left empty.
• These empty slots are generally filled with some extra coils namely called dummy coils.
• These dummy coils are used for providing mechanical balance for the rotor only.
• Dummy coils are similar to other coils and are insulated from other coils.
• They physically exist but are not electrically connected.

Dummy coils exist in only wave winding but not in lap winding.

Mistake Points

Here question has a concern with the other name of dummy coils, hence the correct answer is forced winding.

If the question will have a concern with the application of dummy coil then our answer will be wave winding.