GB1469966A - Method for transformer coil alignment - Google Patents

Abstract

1469966 Transformers MEIDENSHA KK 2 April 1974 [4 April 1973 7 April 1973] 14496/74 Heading HIT A method of making coincident the electromagnetic median planes of a plurality of windings disposed on an iron core limb of a transformer, such planes being defined as those planes perpendicular to the winding axis on each side of which the ampere turns are equal, the method involving monitoring the differential radial leakage flux between the ends of two electromagnetically coupled windings disposed coaxially on said limb one of which is energized the other being open circuit, and moving one of said windings to reduce the differential flux to zero. As described the radial leakage flux is monitored by a saddle coil 30 and indicator 32 which will give a null indication when the median planes are coplanar. Two symmetrically disposed saddle coils (34a, 34b, Fig. 4, not shown) could be used to give numerically equal readings at the coplanar condition. Alternatively, the voltage difference between individual turns of an auxiliary winding 40 could be utilized. In the embodiment of Fig. 8 an uxiliary winding 40 on which is mounted the saddle coil 30 surrounds the outermost 36 of three windings. The winding 40 may be made from a flexible dielectric plate (42, Fig. 9, not shown) bearing conductive strips (44) that may be of metal foil whose ends are joined by wires (46), connector strips (52, Fig. 11, not shown) or by overlapping (Fig. 10, not shown) to form a regular helical short-circuited winding that, with the saddle coil 30, may be used whenever the radial thickness of coupled windings results in too weak a radial field being presented to the unaided saddle coil 30. The saddle coils 30 (34a, 34b) may be disposed on an inner winding and the spacing S may be varied.