# Armature winding- wave In this article I explain the development of wave winding with an example.

Develop a winding diagram for a four pole dc generator with armature having 15 slots. The other specifications of the winding are: simplex, double layer, progressive wave winding.

Observe the above diagram carefully and note the following facts…

1. The armature has 15 slots (for two conductors in each slot)
2. One pole covers 3 slots (6 conductors) and remaining 3 cover 4 slots (8 conductors each).

Follow the steps below to develop the wave winding diagram.

1. Draw vertical lines representing conductors in the slots and number them as shown in the diagram.
2. First N pole covers   first 6 conductors (3 slots) and poles afterwards cover 4 slots (8 conductors) each.
3. Show the instantaneous current directions as shown. (Current direction depends upon the pole under which the conductor is moving.)
4. Use the formulas to find the winding pitch, back pitch and front pitch.
1. Winding pitch=Yw=(conductors+or- 2)/(P/2)
2. Yb+Yf=Yw
5. For the current problem, Yw=16 or 14.
6. Consider Yw=16. To find the back pitch and front pitch, use the rules below:
1. Yb and Yf are odd numbers
2. Yb and Yf are very near to the pole pitch (conductors/poles)=7.5
7. For Yw = 16, Yb=9; yf=7 to satisfy the above conditions.
8. Considering the above values of Yb and Yf, jot down the connection sequence table as: 1^10_17^26_3^12_19^28_5^14_21^30_7^16_23^2_9^18_25^4_11^20_27^6_13^22_29^8_15^24_1
9. From the connection table, note the front connection 30_7 which has both conductors with same direction (entering the generator). Here we can place the -ve brush.
10. Unfortunately, we can’t find the position for the +ve brush on the front or the back connection.
11. Here we reject the value 16 as the winding pitch.
12. Considering the value 14 for the Yw, and applying the rules for Yb and Yf mentioned above, we get Yb=Yf=7.
13. The new connection table now is: 1^8_15^22_29^6_13^20_27^4_11^18_25^2_9^16_23^30_7^14_21^28_5^12_19^26_3^10_17^24_1
14. Note that the 30_7 front connection is available for the _ve brush; and 15^22 is available for the +ve brush (but at the back).
15. At the back, we can’t place any brush because there is no commutator available. The conductor 15 meets commutator segment 4 in the front and conductor 22 meets the commutator segment 11 in the front. So we chose only one of these segments to put the positive brush. We chose segment 4 here.
16. Here ends the wave winding development diagram. (See the diagram below.) 