Page 159 - Electrician - TT (Volume 2)

ELECTRICIAN - CITS

Ring diagram : Fig 4 shows the connection of 6 coils with the commutator segments in the form of a ring diagram.
Sequence diagram : This diagram is mainly used to trace the direction of current in the coil sides (conductors).
With the help of this diagram the brush position can be located. (Fig 5)

Fig 4 Fig 5

Wave winding
Conditions for wave winding : For wave winding, the following terms and conditions should be fulfilled.
• The front pitch YF and back pitch YB should be approximately equal to the pole pitch YP.
• Both the front pitch YF and the back pitch YB should be an odd number.

• The back pitch YB and the front pitch YF may be of the same value or may differ by 2 conductors, in the case
of simplex, and the same or 2 or 4 conductors for multiplex wave winding, depending upon the condition

Y Y
Y A B 2 F approximately
• The average pitch should be as given by the formula

Y Y
Y A B 2 F (or)

No.of conductors 2 x plex
Y A
No. of poles

Z 2
Y A P for simplex wa ve winding

Z 2 for progressiv e simplex wa ve winding
P
Z 2
for retrogress ive simplex wa ve winding
P
Z 4
Y A P for duplex wav e winding
Z 6
Y A for triplex wa ve winding and so on
P

No.of commutator segments m C m
Y C Pairs of poles p/2

where Y is the commutator pitch
c
C = total number of commutator segments
p = number of poles

m = the plex of the winding.
The commutator pitch Ycshall be equal to the average pitch Y . Y = YA
A
c

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