Page 190 - Electrician - TT (Volume 2)

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METHOD 2

Fig 3

IX Cross check the end connections: Write the end connections table as illustrated below in Fig 4 and mark
the direction of currents using the clock rule.

When three phase supply is given to the 3-phase winding, if two phases carry current inwards, the
third phase will carry current outwards.
X Ring diagram

Mark the direction of current in the respective slots and then check the production of the required number of poles
as shown with ring diagram. (Fig 5)

Fig 4 Fig 5

As per the above ring diagram, in all 4 poles are produced. One pole is produced at each of the area contained
by the eight slots. In slots 9,18,27 and 36 coil sides carry current in the opposite directions and hence, the flux in
those slots gets neutralized. This happens in the short chorded winding. Based on the above information draw
the developed diagram.

XI Developed diagram : A developed diagram is shown in Fig 6 in which the connections are shown for the
method 1 referring to Fig 2.
XII Fractional pitches : After the group and lead connections are over, the sleeved joints are to be tied with the
overhang with the help of hemp threads.
Winding is then to be tested and varnished.
The motor is then to be assembled and test run for at least eight hours to check its performance on no load.
Wherever loading facilities are available the newly wound motor can be checked for its load performance.

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