A turn consists of two conductors situated one pole pitch apart and connected in series.
A coil may consist one turn or several turn situated on one coil pitch apart. The coil consist one turn is called single turn coil and the coil consist more than on turn is called multi turn coil.
4. Coil side.
5. Coil span or coil pitch
The distance between two coil sides is called coil span or coil pitch
6. Pole pitch
The distance between starts of two continuous poles (N & S ), is called pole pitch it is generally taken 180 degree.
7. Phase spread
The distance between start of two continuous phase is called phase spread, it is 120 degree.
• Classification of motor winding
• According to pitch
According to pitch there are two type of winding
If coil span is to one pole pitch or 180 degree. Then it is called full pitch winding.
2. Short pitch winding
If coil span is less than one pole pitch then it is called short pitch winding. Here coil span is 150 degree.
Advantage of short pitch winding
It is economical
It is light in weight
Disadvantage of short pitch winding
Possibility of generation of harmonics and vibration in shaft.
• According value of slots/pole/phase
In this base it is divided in two parts
1. Integral slot winding
If number of slots/pole/phase is a integer value then it is integral slot winding
2. Fractional slots winding
If number of slots/pole/phase is not a integer value then it is fractional slot winding
Advantage fractional slots winding
- The fractional slots winding make it possible to reduce the no of slot in motor and that’s why to reduce the size and price of motor.
disadvantage of fractional slots winding
- The motor having fractional slots winding are less efficient and capable to carry the load.
• According layer of winding
1. Single layer winding
If each slots of motor consist one coil side then it is called single layer winding.
2. Double layer winding
If each slot of motor consist two coil sides than it is called double layer winding.
Advantage double layer winding
It is increase the load carrying capacity of the motor.
disadvantage of double layer winding
It increase the size and prize of motor.
• According to connection of motor
1. Lap winding
The winding in which the conductor comes in back word direction to connect the next conductor in the previous pole are called lap winding it is used that time when motors required more current, less voltage.
2. Wave winding.
The winding in which the conductor doesn’t returns but those in forward direction to connect to the nest conductor situated in the pole are called wave windings.