Lap Winding vs. Wave Winding

Attribute	Lap Winding	Wave Winding
Number of parallel paths	More than two	Two
Number of brushes	Equal to number of poles	Less than number of poles
Connection of coils	Connected in series	Connected in parallel
Coil pitch	Equal to pole pitch	Not equal to pole pitch
Uses	Used in low voltage applications	Used in high voltage applications

Introduction

When it comes to designing electrical machines, the choice between lap winding and wave winding is crucial. Both winding techniques have their own set of attributes that make them suitable for different applications. In this article, we will compare the attributes of lap winding and wave winding to help you understand the differences between the two.

Construction

Lap winding is a type of winding where the end of one coil is connected to the beginning of the next coil. This creates a series of coils that are connected in a loop. On the other hand, wave winding is a type of winding where the end of one coil is connected to the beginning of the next coil, but in a zigzag pattern. This creates a wave-like pattern in the winding.

Number of Parallel Paths

One of the key differences between lap winding and wave winding is the number of parallel paths that are created. In lap winding, the number of parallel paths is equal to the number of poles in the machine. This means that each coil is connected in series with the next coil. In wave winding, the number of parallel paths is equal to two times the number of poles in the machine. This allows for a more distributed current flow in the winding.

Coil Span

Another important attribute to consider when comparing lap winding and wave winding is the coil span. In lap winding, the coil span is equal to the number of poles in the machine. This means that each coil spans across one pole pitch. In wave winding, the coil span is equal to two times the number of poles in the machine. This allows for a shorter coil span, which can lead to a more compact winding design.

Distribution of EMF

When it comes to the distribution of electromotive force (EMF), lap winding and wave winding have different characteristics. In lap winding, the EMF is distributed evenly across all the coils in the winding. This can help reduce the risk of hot spots and improve the overall efficiency of the machine. In wave winding, the EMF is distributed in a wave-like pattern, which can help reduce the effects of armature reaction and improve the commutation process.

Ease of Repair

One practical consideration when choosing between lap winding and wave winding is the ease of repair. Lap winding is generally easier to repair because each coil is connected in series with the next coil. This means that if one coil fails, it is easy to identify and replace the faulty coil. On the other hand, wave winding can be more challenging to repair because of the zigzag pattern of the winding, which can make it difficult to trace and replace a faulty coil.

Applications

Both lap winding and wave winding have their own set of applications where they excel. Lap winding is commonly used in machines where a high current density is required, such as in traction motors and industrial generators. Wave winding, on the other hand, is often used in machines where a more distributed current flow is needed, such as in alternators and synchronous motors.

Conclusion

In conclusion, lap winding and wave winding are two distinct winding techniques that offer different attributes and advantages. Lap winding is characterized by a series connection of coils, while wave winding features a zigzag pattern of connections. The number of parallel paths, coil span, distribution of EMF, ease of repair, and applications are all factors to consider when choosing between lap winding and wave winding. By understanding the differences between these two winding techniques, you can make an informed decision when designing electrical machines.