Traction Rolling Stock - Indian Railways Institute of Electrical ...

Leg I A I = 704 cm 2 (Regulating transformer)
Leg II A II = 1295 cm 2 {Fixed ratio main
Leg III A III = 704 cm 2 transformer}
FIG 1.2.1 Leg flux diagram
Leg I carries the winding of the regulating transformer stepping down the voltage of the
overhead system to a value permissible for the equipment.
The series winding A 32 ...
A 33 has 80 turns.
Cross sectional area = 27.45 mm 2
The main winding A0 ......
A 32 has 960 turns
Cross sectional Area = 27.45 mm 2
According to the above, the complete winding of the regulating transformer has:
N 1 = 80 + 960 = 1040 turns
According to the actual position of the tap changer.
The active number of turns varies from
Pos. 0,1,2,3,4....... 28,29,30,31, 32.
NR = 0, 30,60, 90, 120....... 840,870,900,930,960 turns.
In addition to the winding of the regulating transformer leg I carries the electrically
separated winding a0...al of the auxiliary circuits also. This winding has 18 turns.
Cross sectional area = 248 mm 2
The legs II and III carry the primary and secondary windings of the main transformer.
The induction effect of the winding of leg III on the winding of leg II varies according to the position
of the tap changer.
The design of the two legs is similar, the difference being in the cross sectional area
only. The primary windings of both legs are connected in series and each leg has