GB1198669A - Ballast Transformers - Google Patents

Abstract

1,198,669. Transformers. SYLVANIA ELECTRIC PRODUCTS Inc. 9 Oct., 1967, No. 46036/67. Heading H1T A transformer, which may be an autotransformer, for use with electric discharge lamps comprises a first magnetic core 1 providing a magnetic circuit closed except for an air-gap 25, and a second magnetic core 2 including one or more bridged air-gaps 26, 27, a portion of the first core containing the air gap being close to but spaced from a portion of the second core, a primary coil 3 encircling said portions of the two cores and a secondary coil 4 encircling a further portion of the second core which further portion contains a bridged air-gap. Laminations in the leg opposite to that containing the air-gap in the first core are interleaved as at 29 and the laminations forming the bridged air-gaps in the second core are also interleaved, the region of the interleaved joint in one leg of the second core being offset relative to the region of the interleaved joint in the opposite leg of that core. The cores are mounted on a supporting plate 12, portions (42) of which (Fig. 4, not shown), are bent to grip the cores, and formed with tabs projecting into the space between the cores, the cores resting on ribs (46) formed on the plate 12. A bolt 23 extending through the plate 12 and space (37) between the cores extends at its upper end through a channel-shaped plate 20 such that when nut 24 is tightened on the bolt the cores are firmly clamped. The primary coil 3 may have a tap (7) (Fig. 3, not shown).