Specifications

65
S.No.
Top coil Side
(-Y
f
)
Bottom coil Side
(+Y
b
)
11 8
23 10
35 12
47 2
59 4
611 6
From equation 3.3, the winding Pitch, Y = +2 for progressive winding (even integer). From
equation 3.5, the front pitch, Y
f
= Y
b
– Y = 7 – 2 = 5 (odd integer). Starting with coil side 1 (back
end side), back pitch is added to obtain the bottom layer coil side, ie., 8 (back end side). To the
coil side 8 (front end side), front pitch is subtracted to obtain the top layer coil side, ie., 3 (front
end connection). Proceeding in similar way, all the coil sides are connected and a winding
table, as shown in Table 5.1.
Table 5.1 : Winding table for 2 pole, 6 slot simplex lap winding
To draw the main winding diagram, first draw 6 solid vertical lines (equal to no. of coils) of
equal length and equal distance. Next, draw 6 dotted lines nearer to the solid lines of same
length and distance, as shown in Fig. 5.1.
Assign odd numbers to the top layer coil sides of the solid lines and even numbers to the
bottom layer coil sides of the dotted lines.
Give the back end and front end connections with reference to the Table 5.1. Then, draw
solid vertical lines (equal to no. of coils) from the top mid-point of each front end connections, as
shown in Fig. 5.1.
Represent commutator segments (equal to no. of coils) by rectangular boxes below the
front end connections, as shown in Fig. 5.1.
Divide the armature slots (or coils) by the number of poles. This gives the allocation of coil
sides to pole regions. In this example, the number of slots are 6 and number of poles are 2. So,
the north pole, N region, covers first 3 coils (say 1 to 6) in Fig. 5.1. The south pole, S covers coil
sides 7 to 12.
Fig. 5.1- Main winding diagram
13 5
7
11
9
24 6
8
12
10
123456
+ -
AAA
Front end
coil sides
Commutator
segments
Back end
coil sides
N
S
27
9
4
11
9
11 6
24