GB1385224A - Electric transformer - Google Patents

Abstract

1385224 Voltage regulating transformers WESTINGHOUSE ELECTRIC CORP 3 March 1972 [23 April 1971] 10080/72 Heading H3X [Also in Divisions H1 and G3] The invention provides a readily adjustable core construction for a parametric voltage regulating transformer. A known device whose manner of operation is described in patent Specification 1,308,966 is shown in Fig. 1, and has input and output windings 46, 52, the latter being connected to a capacitor 54 to form a resonant circuit. The core leg 26 normally prevents interaction between the input and output windings, but during a small part of the input waveform cycle, say 15 degrees, this leg saturates and energy is coupled from the input to the output. Because the input and output are isolated except for this small part of the cycle the voltage stabilization and filtering are high. The present invention provides core structures in which the air gap 60 is readily adjusted to optimize the waveform and stability of the output. One embodiment is shown in Fig. 4, and has the air gap defined by non-magnetic spacers at 96 and 98, these spacers being replaceable by ones of different thickness. The core is made by winding a length of suitable material, e.g. grain oriented silicon steel, to form a region which encircles the input winding, a region which encircles the output winding and a region which surrounds the first two regions; the structure is cut to separate the central region 72 from the input and output regions 64, 68, the windings being slid on to these latter regions before reassembly. The spacers 96, 98 may then be chosen as required. In another embodiment, Figs. 5, 6, 7 (not shown), two C cores are made by winding and cutting an oval core; these cores carry the input and output windings, and are butted against a magnetic shunt and spacers which act in a manner similar to the central region of Fig. 3. Fig. 8 shows an alternative where the C cores are replaced by wound E cores separated by a laminated plate 154 and spacers 160. The windings (not shown) are on limbs 170, 176. These E cores may be laminated structures, Fig. 9 (not shown). The central limbs carrying the windings may be of twice the area of the other limbs, Figs. 11, 12 (not shown). In Fig. 14 a laminated structure is shown, using modified E laminations with L laminations. It will be seen that the laminations alternate so that one E lamination overlies an L lamination and vice-versa. The assembly is clamped by bolts through the holes 290, leaving a gap between the lamination ends at 276. By making the bolt holes oversize or elongate the laminations can be moved to adjust the gap size. The capacitor may be tapped into the output winding, or may have a separate output winding, Figs. 7, 10, 13 (not shown).