1. Winding Diagrams: (i) DC Winding diagrams (ii) AC Winding Diagrams
Terminologies used in winding diagrams:
Conductor: An individual piece of wire placed in the slots in the machine in the magnetic field.
Turn: Two conductors connected in series and separated from each other by a pole pitch so that the emf
induced will be additive.
Coil: When one or more turns are connected in series and placed in almost similar magnetic positions. Coils
may be single turn or multi turn coils.

4. Single layer winding: Only one coil side placed in one slot.
Double layer winding: Two coil sides are placed in a single slot.

5. Classification of windings: Closed type and open type winding
Closed type windings: In this type of winding there is a closed path around the armature or stator. Starting
from any point, the winding path can be followed through all the turns and starting point can be reached.
Such windings are used in DC machines.
Open windings: There is no closed path in the windings. Such windings are used in AC machines.

6. Pole Pitch: Distance between the poles in terms of slots is called pole pitch.

7. Three phase AC-Single layer wave winding-24 slot, 3phase, 4 pole machine

8. Winding table

12. Draw the developed winding diagram of a 3 phase induction motor with 18 slots, 2 poles, single layer, full pitched lap winding with delta connection.
Soln: No. of slots per pole per phase = 18/(2 x 3) = 3
Pole pitch = no. of conductor / pole = 18/2 = 9
Slot angle = 180/ pole pitch = 180/9 = 200
Full pitched winding = coil span = 180
Coil span = winding pitch/slot angle = 180/20 = 9 slots
Winding Table:
Phase 1st pole 2nd pole
R = = 20 (2)
3 + 9 = 12
= 22(4)
B = = 24 (6)
Y = = 26 (8)
9 + 9 = 18
Connections: Rs = 1, Ys = /slot angle = 1+120/20 = 7; Bs = /slot angle = /20 = 13