GB949213A - Improvements in or relating to electric power transformers - Google Patents

Abstract

949,213. Transformers. ENGLISH ELECTRIC CO. Ltd. June 17, 1960 [June 19, 1959], No. 21120/59. Heading H1T. To reduce the noise output from a transformer, steel plate cladding is held at a distance from the tank to reflect incident sound waves, the cladding having, by virtue of its dimensions and mounting, a natural frequency substantially less than that of the current in the coils. The cladding plates 18 are supported by horizontal spring strips 15 bolted to brackets 14 themselves welded to tank 10. Springs 15 are bolted to horizontal channel members 16 welded to vertical strips 17 to which are clamped plates 18 by fish plates 21, felt pads 19, 22, providing damping. This arrangement gives considerable vertical, but smaller horizontal, stiffness. Lower edges of plates 18 rest in foam-rubber filled troughs 24. Insulators 12, 13 pass through holes in dome 26, which rests on flexible material on plates 18, and are sealed by rubber diaphragms 27, the oil cooling pipes similarly having rubber diaphragms sealed with an annular clamp (Fig. 5, not shown). The space 23 is filled with energy-absorbing material such as glass-wool. In an alternative arrangement for attaching the cladding to the tank, resilient vertical strips are welded at their free ends to horizontal channel members attached respectively to plates and tank (Fig. 6, not shown).