In an electrical machine, the winding can be classified into two types
- Concentrated winding
- Distributed winding
What is a concentrated winding:
Concentrated type of winding can be done when the total number of poles in the armature is equal to the number of slots of the armature coil. Look at the image, the winding the total coils is wound in the single slots.
All the turns of this type of winding have the same magnetic axis, for example, the transformer winding. This type of winding gives maximum output voltage but not exact sinusoidal because it is independent of pitch and distribution factor.
What is Distribution Winding?
Distributed winding is distributed along the air gap. In this winding poles are not equal to the number of slots. It does not have the same magnetic axis. The emf induced in the distributed winding is less due to the presence of pitch factor and distribution factor. Distributed windings are used in DC machine, synchronous machine and induction machine.
Advantages of Distributed Winding:
- It reduces harmonics present in the generated emf which also improves the sine waveform.
- It reduces armature reaction and improves cooling.
- The coil is distributed over the slots, so the core (copper and iron) is fully used.
- It improves the mechanical strength of the winding.
Difference between Concentrated and Distributed Winding:
Look at the image at which you can easily differentiate the windings.
|Winding Will be done in a single slot
|Winding will be done throughout the slot
|The emf developed in the winding is the directly proportional number of turns and independent of the pitch factor and distribution factor.
E = 1.414πfNØ
|Pitch factor and distribution factor are contributing the emf development.
E = 1.414πKpKdfNØ
|Example: Transformer, field windings etc.
|Electrical AC single-phase and three-phase induction motor and DC motors
|Slot in the armature is equal to the number of poles
|A number of poles is not equal to a number of slots.