Specifications

49
Fig. 4.18 - 3 phase 2 pole 24 slots single layer winding main winding diagram (half coil)
Whole Coil Winding
Total number of coils =
24
4
= 6; Coils per phase =
12
3
= 4; Number of coils of groups per
phase = 3 x 2 = 6
If the first phase, say R or A phase starts at slot no.1, the Y or B phase should start at 120
0
/15
0
= 8 slots away ie., in slot (1 + 8 = ) 9, and the B or C phase should start at (9 + 8 =) 17.
Starting with coil in slot no. 4, the start of R phase lies in slot no. 4, that of Y phase in slot no.
(4 +8 = ) 12 and that of B phase in slot no. (12 + 8 = ) 20.
Fig. 4.19 gives the coil group connections for whole coil winding for each phases.
To draw the main winding diagram, draw 24 solid lines of equal length and distance equal to
the number of slots, as shown in Fig. 4.20. For series connection, the finish of first coil of a
phase is connected to the finish of the second coil group of the same phase. The start of the
second coil group is connected to the start of the third coil group and so on. In Fig. 4.20, R
S
, R
F
,
B
S
, B
F
, Y
S
, and Y
F
indicate the starting and finishing ends of RBY phases respectively.