Page 156 - Electrician - TT (Volume 2)

ELECTRICIAN - CITS

Fig 11 Fig 12

Progressive lap or wave winding : In progressive lap or wave winding, the front pitch YFwill be less than the
back pitch YB, i.e. as you lay the coils clock-wise, the connections to the commutator segments will also proceed
clockwise as in Figs 13a and b. In progressive winding, Yc is referred to as +1.
Retrogressive lap or wave winding: In retrogressive lap or wave winding, the front pitch Y will be greater than
F
the back pitch Y , i.e. as you lay the coils clockwise, the connection to the commutator segments will proceed
B
anticlockwise as shown in Figs 14 a & b. In retrogressive winding Yc is represented as -1.
Fig 13 Fig 14

Simplex lap and wave winding - developed diagram

Objectives: At the end of this lesson you shall be able to:
• state the conditions for Lap winding and wave winding
• calculate and draw the developed ring diagram for simplex lap and wave winding.

Development winding diagram : To draw the development winding diagram, the winding particulars like number
of conductors, number of poles, pitches, types of windings etc. are required. For any DC armature winding, there
shall be as many coils as the number of commutator segments. Further, the number of coils will be the multiple
of the number of slots, i.e. for a single layer, there will be double the number of slots as that of the commutator
segments and for a double layer there will as many slots as the commutator segments.
Lap winding

Conditions for lap winding : For lap winding the following terms and conditions are to be fulfilled.
• The front pitch YFand the back pitch YBshould be approximately equal to the pole-pitch YP.
• Both the front pitch YFand the back pitch YBshould be an odd number.
• The back pitch YBand the front pitch YFshould differ by 2 conductors, for simplex lap winding. In the case of
multiplex winding, it is equal to 2 x No. of `plex’.

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CITS : Power - Electrician & Wireman - Lesson 86-92 CITS : Power - Electrician & Wireman - Lesson 86-92