Specifications

42
To draw the main winding diagram, draw 12 solid lines of equal length and distance equal to
the number of slots, as shown in Fig. 4.8. 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. 4.8, R
S
, R
F
, B
S
, B
F
, Y
S
,
and Y
F
indicate the starting and finishing ends of RBY phases respectively.
Fig.4.8 - 3 phase 2 pole single layer winding main winding diagram (Whole coil winding)
Mush winding
In drawing this winding, the slots are numbered from 1 to 12 and the long and short sides
are alternatively drawn, as shown in Fig. 4.9
Fig.4.9 - 3 phase 2 pole single layer winding main winding diagram (mush winding)
If the first phase, say R or A phase starts at slot no.1, the Y or B phase should start at 120
0
/
30
0
= 4 slots away ie., slot (1 + 4 = ) 5, and the B or C phase should start at (5 + 4 =) 9.
Slots per pole per phase = = 2. Thus a phase group has 2 slots.
Coil span =
12
2
= 6 slots. This is an even number and hence winding is not possible
with a coil span of 6 slots. So a coil span of 5 slots is used.
Starting R phase in slot no. 2, the coil side in slot no. 2 is connected to the coil side (2 + 5
= ) 7. The coil side 8 is connected to coil side (8 + 5 = ) 13, ie., 1. The coil groups are connected
12
3x2