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…
- The armature has 15 slots (for two conductors in each slot)
- 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.
- Draw vertical lines representing conductors in the slots and number them as shown in the diagram.
- First N pole covers first 6 conductors (3 slots) and poles afterwards cover 4 slots (8 conductors) each.
- Show the instantaneous current directions as shown. (Current direction depends upon the pole under which the conductor is moving.)
- Use the formulas to find the winding pitch, back pitch and front pitch.
- Winding pitch=Yw=(conductors+or- 2)/(P/2)
- For the current problem, Yw=16 or 14.
- Consider Yw=16. To find the back pitch and front pitch, use the rules below:
- Yb and Yf are odd numbers
- Yb and Yf are very near to the pole pitch (conductors/poles)=7.5
- For Yw = 16, Yb=9; yf=7 to satisfy the above conditions.
- 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
- 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.
- Unfortunately, we can’t find the position for the +ve brush on the front or the back connection.
- Here we reject the value 16 as the winding pitch.
- Considering the value 14 for the Yw, and applying the rules for Yb and Yf mentioned above, we get Yb=Yf=7.
- 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
- 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).
- 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.
- Here ends the wave winding development diagram. (See the diagram below.)
You can download here another wave winding example.