Abstract: Inside the gradient coils in the magnet system of a nuclear magnetic resonance apparatus there is arranged a sleeve which forms a noise-absorbing shield between the gradient coils and the measurement space. The shield is preferably formed by an evacuated space between the sleeve and a support for the gradient coils. This space is then provided with elastic vacuum seals at its axial ends.

Abstract: A hollow sound damping plate is arranged between a transformer core and an internal limiting surface of a transformer tank filled with insulating fluid. At least one compressive-force transmitting spring member (8) is arranged between the front wall (6) and the rear wall (5).

Abstract: A noise-reduction device for a stationary induction apparatus which device comprises a sound insulation panel attached to reinforcing channels provided at the periphery of a tank of the stationary induction apparatus so as to block noises emitted from the outer surface of the tank, a weighty body attached to the sound insulation panel for reducing vibrations of the sound insulation panel and a dynamic damper of which the natural frequency can be adjusted to be made equal to the vibration frequency of the weighty body so as to cancel the vibrations of the weighty body.

Abstract: The current transformer for instruments for measuring electric currents includes a magnetic core that has two cores and an inductive current divider with three parallel current paths. The current dividers form, together with cores, two current transformer stages whose magnetic fluxes mutually cancel one another. In a current transformer for AC currents having a DC component, the ratio of the ohmic resistances of the individual current paths is in direct relation to their transformation ratio.

Abstract: Transformer having an active part thereof disposed in an oil-filled, smooth-walled tank having side walls braced by ribs secured by welding and subdivided into wall-high panels, the panels, respectively, including a sheetmetal wall having a resonance frequency f.sub.o smaller according to the function f.sub.o =(S.multidot.k.sub.f)/B.sup.2 then twice line frequency, wherein S is the thickness of the sheetmetal in cm, B the net panel width in cm, and k.sub.f a constant having an absolute magnitude which depends upon the length-to-width ratio of the panel, upon the modulus of elasticity, upon the transverse contraction and upon the specific gravity of the material used therefor.

Abstract: A transformer is fixed between two electrically insulating plates extending through a hollow porcelain tube connected at both ends to an upper and a lower tank through packings respectively and two compression controlled helical springs are disposed in the upper tank to controllably tension the mating electrical insulating plates with respect to the lower tank. The upper tank is also connected to the lower tank by means of at least three supporting rods disposed on the outside of the porcelain tube and including one end fixed to the upper tank and the other ends threaded and coupled to threaded studs welded to the lower tank through turnbuckles with a cushion interposed between the supporting rods and the porcelain tube.

Abstract: A transformer including a lamination core of band iron and a magnetic screen which consists of a wound iron band arranged around the lamination core (5) and which is secured to the core by means of expansion wedges provided in the space between the core and the screen 13. The expansion wedges (7) extend transversely of or at an angle with respect to the winding direction of the wound iron band.

Abstract: A high frequency coil including an inductance device formed by fitting a pair of electrode caps at both ends of a ferrite magnetic core wound by a winding on a peripheral surface of the core; a heat resistant electric insulating coated layer formed on the peripheral surface of the inductance device and a heat resistant electric insulating resilient tube fitted onto the peripheral surface of the coated inductance device.

Abstract: A device for chocking an inverted type current transformer when transported on its side.It comprises at least one jack (12) within the metal enclosure (1) but operable from outside the latter and disposed, during transportation of the transformer on its side, between the transport platform (36) and the magnetic core (8) of the current transformer to eliminate any cantilever loading.

Abstract: A static induction apparatus including a vessel for containing a main body of the static induction apparatus, a plurality of reinforcing support members secured to side plates of the vessel and a sound reducing structure. The sound reducing structure includes a plurality of sound reducing members supported between the reinforcing support members and each including a sound insulating panel composed of high damping metal plate, a resilient plate formed of thin metal sheet material interposed between the sound insulating panel and the reinforcing members, and a weight member secured to the vicinity of the boundary between the sound insulating panel and the resilient plate.

Abstract: Liquid-cooled transformer for large power ratings, including a tank having a bottom with cutouts formed therein, large-area base plates resting on the bottom of the tank, an active part having ends and a pressure device being fastened to the base plates, at least one of the base plates being disposed under one of the ends of the active part, the at least one base plate having outside corners being disposed above the cutouts formed in the tank bottom, stopping blocks positively locking the outside corners in position without play, and inserts supporting the stopping blocks and oil tightly closing off the cutouts.

Abstract: Liquid-cooled transformer for large power ratings, including a tank having a bottom, large-area base plates resting on the tank bottom, an active part and a pressure device fastened to the base plates, a plurality of synthetic resin-filled cups disposed in the tank bottom, a post supported by and projecting downward from the base plates being immersed in each of the cups for horizontally locking the base plates relative to the tank bottom.

Abstract: A tuned sound barrier for machines which radiate sound primarily at a few constant, discrete frequencies includes an array of mechanical resonators distributed over the surface of a sound barrier. Each resonator of the array is tuned to present a high mechanical impedance to transmission of mechanical vibration at one of the discrete frequencies emitted by the source machine. The tuned sound barrier may be either a free-standing sound barrier or an attachment to a housing for the machine.

Abstract: This invention relates to an isolator for a large-sized static induction apparatus such as transformer and reactor. The static induction apparatus wherein a sound insulation panel is mounted through an elastic body on a reinforcing channel which is disposed on a side plate of an oil tank receiving a main device of the apparatus therein, is characterized by disposing a looped weight beam near that part of the sound insulation panel on which the elastic body is installed.With such construction, noise can be effectively reduced while imparting a satisfactory supporting strength to the mounting part of the sound insulation panel.

Abstract: A zero-phase current transformer for use as a leakage current detecting element in a leakage current interrupter in which two magnetic materials of different permeabilities are provided so as to eliminate a range where the leakage current interrupter is inoperable without lowering its ability to distinguish noise components. The different magnetic materials may be provided as a single core constructed by mixing the materials of different permeabilities. Otherwise, the materials can be provided as annually-shaped magnetic pieces stacked one on top of the other. Still further, the materials of different magnetic permeability may be provided as bands of materials interwound to form alternating layers or one of the materials may be provided as at least a portion of a protective case.

Abstract: A plurality of rod-like vibration elements are fixed onto the outer circumferential surface of the exterior wall of the tank of a transformer. Each rod-like vibration element consists of a beam portion extending in parallel to the outer circumferential surface of the exterior wall and a fitting portion having one end thereof fixed to the beam portion and the other fixed onto the outer circumferential surface of the exterior wall of the tank. The width D of the beam portion in the direction perpendicular to the outer circumferential surface of the exterior wall of the tank is selected to be greater than the width W of the beam portion in the direction at right angles to the width D.

Abstract: A choke for use with alternating current has a ventilated housing with a perforate inner wall and an imperforate outer wall to which the choke is connected vibration-elastically. The space between the inner wall and the jacket is filled with a sound-absorbing material.

Abstract: A sound reducing baffle for air cooled electrical apparatus with a ventilated enclosure comprised of a box-like closure member positioned in front of the ventilating openings and open at the back and top thereof to permit the transfer of air.The sound is attenuated by reflections and absorption within the baffle with little or no interference with the transfer of cooling air to and from the enclosure.

Abstract: In a gap winding type electric rotary machine, a stator winding consisting of a plurality of stator coils is mounted on the inner surface of a stator core within the air gap defined by the clearance between the stator core and the rotor core, in such a manner that the stator coils are grouped together in a plurality of stator coil units and each stator coil unit is encapsulated in a solid casing comprising an outer cover fixed to the inner surface of the stator core through an elastic sheet and an inner cover closing the outer cover. The inner clearance within the solid casing is also provided with an elastic sheet.

Abstract: An iron core for induction apparatuses is constructed of at least one main leg and yokes including side yokes comprising laminations of magnetic material. The magnetostriction of the yokes is smaller than that of the main legs, so that the vibration of the inductors is easily suppressed without any special means. Noise, which otherwise might arise from the vibration is thus reduced sharply.

Abstract: A ballast can be mechanically and thermally isolated from the mounting plate which acts as a heat sink by securing a pair of L-shaped channels to the bottom of the ballast with the depending leg of each channel being disposed in intimate sliding engagement with the flat surface of a respective C-shaped channel member which is secured to the mounting plate. Vibration damping washers are disposed between the L-shaped channel member and the C-shaped channel member to prevent vibrations from being transmitted from the ballast to the base while still permitting heat dissipation through the superimposed sliding surfaces of the channels.

Abstract: A reactor winding in the form of a high current, multi-turn, multi-layer insulated coil stack embracing an inner member of a magnetizable core assembly of a reactor is resiliently supported by the outer member of the core assembly by inserting a plurality of ripple spring sheets of non-magnetic material between the outer member and selected adjacent surfaces of the outer periphery of the windings. The inner core member is resiliently supported within the coil stack by an additional plurality of ripple spring sheets disposed between adjacent surfaces of the coil stack and inner core member. Ripple spring sheets are also positioned between adjacent surfaces of the inner and outer core members. The ripple spring sheets are preferably disposed between flat side sheets to provide uniform distribution of the spring forces.

Abstract: A ferrite magnetic core includes a one-piece rectangular outer member with aligned circular apertures in which the ends of a cylindrical center member are retained to thus establish a radial air gap. Radial magnetic forces acting on the core members are summed to zero to theoretically eliminate movement and result in low acoustic noise in high operating frequency power inductors and transformers. A magnetic bridge is added to reduce air gap fringing flux outside the core. Other modifications and a "C" core configuration are described.

Abstract: An encapsulated transformer in which the coil and core assembly of the transformer is encapsulated within a jacket of non-flexible epoxy resin, and a cushion of closed-cell foam rubber lies between the jacket and the coil and core assembly to preserve the integrity of the jacket while enabling thermal expansion and contraction of the core and coil assembly. Electrical contact members are integral with the jacket and are electrically connected to the core and coil assembly by flexible electrical leads.

Abstract: There is disclosed a light fixture having a ballast therein comprising a substantially enclosed steel case which is mounted on a wall of the steel housing of the fixture and substantially filled with a potting compound in which a magnetic core and coil device is embedded.