Armature winding classified in to two types lap winding and wave winding. If we talk about armature winding it is very important part of the rotating machine where energy conversion process performs.
in case of generator mechanical energy converted into electrical energy and in case of motor electrical energy converted into mechanical energy where we use either lap winding and wave winding on armature
Lap winding
- Lap winding is used for requirement of low voltage and high current.
- in lap winding number of parallel path equal to number of poles that is ( A = P )
- meaning of parallel path is total number of path by which current will flow between the terminal and it is denoted by (A).
different types of lap winding
- Simple lap winding : in simplex lap winding number of parallel path is equal to the number of pole ( A = P )
(coil – 2) will start from the ending point of (coil – 1) , mean next coin will start from the end point of first coil.
2. Duplex lap winding : duplex lap winding number of parallel path of winding is twice with respect to poles. ( A = 2P )
as you can see in the diagram here there are three commutator segments , turning of first coil started from the commutator segment -1 and after two turns of coil it ends on the commutator segment – 2 And turning of 2nd coil starts from the commutator segment – 2 and after two turns of the coil It ends on the commutator segment – 3 and alternate magnetic pole developed on the coil.
3. Triplex lap winding : in triplex lap winding number of parallel path is three times of poles . ( A = 3P )
as you can see in the above diagram there are total three commutator segment shown in the figure first coil started from the committed segment 1 and after 3 terms of the coil It ends on the commutator segment – 2 and second coil starts from the commutator segment -2 or we can say end of the first coil and after two turns of the second coil It ends on the commutator segment – 3. And this process will continue on next commutator segments.
NOTE ( lap winding and wave winding )
- Lap winding is used in that type of application where need of or we can say requirement of low voltage and high current operation at that place generally we use lap winding.
- in case of lap winding Low EMF induces compare to wave winding
- if we provide lap winding in any rotating machine then cost of machine increases .
Wave winding
in wave winding only two parallel path are provided between the negative and positive brush. This type of winding is used where we have requirement of high voltage and low current.
as you can see in the above diagram here coil – 1 is placed on commutator segments and coil – 2 started from end point of coil – 1 and ends on next commutator segment.
starting pole of (coil – 1) and starting pole of (coil – 2) remain always same. And end point of the first coil and starting point of the second coil will be always different. In case of wave winding coils are connected in series so it is also called as series winding.
in case of wave winding number of brushes is equal to the number of parallel path ( B = 2 ) .
Wave winding is categorised into two types
- retrogressive wave winding : in case of retrogressive wave winding after one revolution of armature, the copper coil falls in to a slot left of its starting slot.
- Progressive lap winding : in case of progressive wave winding after one revolution of armature coil , the coil Falls into slot right of it’s starting slot
Full pitch coil
when the angular distance between coil to sides is electrically 180° then it is called as full pitch coil
Net voltage = EC1 – EC2 = +E – (-E) , Net voltage = 2E
Short pitch coil
if the angular distance between two coil sides are less than the pole pitch then it is called as short pitch or fractional coil.
to understand the short pitch coil we consider two sides of the coil as you can see in the diagram second side of the coil is B° shorted . So distance between both side of the coil will be (180° – B) , where B – short pitch angle.
Lap winding and wave winding characteristics
Lap winding
- lap winding is generally used in DC machine like Dc generators and DC Motors where requirement of high current and low voltage.
- lap winding create different parallel paths through which current can be flow, that increases the current carrying capacity of the electrical machine.
- lap winding is a specially used at that type of application where requirement of high current and low voltage that makes it easy or suitable for multipolar DC generators.
- due to multiple parallel paths in the lap winding commutation get improved, reducing sparking at the brushes so reliability get improve.
- lap winding is generally suitable for large size machine where it allow for the use of thinner conductors that reducing the overall cost and weight of the DC machines.
Lap winding and wave winding characteristics
Wave winding
- in case of wave winding always have two parallel path for flow of current, regardless of the poles, where the number of parallel paths equal to the number of poles.
- due to two parallel path in wave winding it gives higher voltage output for a given number of conductors compared to lap winding so this type of winding is used specially for that type of application where requirement of high voltage and low current.
- wave winding has generally very simple construction then lap winding so it is easy to construct where winding or design into the electrical machine.
- since we used two parallel path in wave winding that provide uniform torque so we achieve smoother torque .
- this type of winding provides good commutation characteristics that is very essential for batter rotation of rotating element and efficiency of the machine.
Conclusion : so this is all about lap winding and wave winding the main difference between lap winding and wave winding , lap winding is used for the application of high current and low voltage whereas wave winding is used for the application of high voltage and low current. so i hope you will get detail about lap winding and wave winding. in previous article i have describe about different machine topics and this lecture totally based on lap winding and wave winding – VIDEO