DE2656700A1 - Laminated core for power transformer - has stepped construction with stiffening clamps to shift resonant frequency to provide resistance to vibration - Google Patents

Abstract

A laminated core for a power transformer has a stepped cross-section and the laminations are braced on three sides by profile carriers which are rigidly bound to the frame of the transformer. U-shaped profile carriers (3, 4) are clamped on three sides around the widest (3) and smallest (4) groups of laminations and to the frame and/or the yoke clamps. By this method the structure is stiffened and the resonant frequency altered thus increasing the resistance of the transformer to the effects of earthquakes. In an alternative construction the frame is stiffened by a lamination clamp having a double-T shaped profile which is placed within a central opening in the core.

Description

Core layered from sheet metal for trans-

formators and the like.

The present invention relates to a laminated sheet metal Core for transformers and the like, consisting of at least one wound core leg and in the end areas layered yokes overlap with lateral yoke press irons and stand or chassis connected to the lower yoke press iron.

Especially in connection with the recently increased security requirements for nuclear power plants there is also the safety requirement for the systems installed in these systems Transformers increased. In particular, there are also requirements for earthquake resistance of transformers have been added.

The core of a power transformer is known for reasons the lowest possible own losses from highly siliconized today almost exclusively layered cold rolled sheet. Such a device is normally set up vertically core therefore represents a relatively unstable structure that only depends on the and winding compression or compression with bandages held together friction generated and for r.

the support against the windings is stiffened.

The natural frequencies of such a transformer active part lie thus in a frequency range that is used in earthquake waves and similar shock loads may be included.

The object of the present invention is to strengthen the core in this way and stiffen that natural frequency range out of the critical output range pushed out upwards. The active part is then only subject to those that occur Acceleration forces, but not the force increases associated with the resonance.

This object is achieved according to the invention in that the core legs by adding profile girders that form part of the stepped cross-section of the Core limbs comprise three sides, are stiffened, and that the ends of the profile girder with the yoke press iron and / or the frame non-positively and rigidly connected are.

Exemplary embodiments of the invention are illustrated with the aid of the accompanying drawings and how it works.

Fig. 1 shows a cross section through a generally perpendicular standing and vcin the winding not shown coaxially surrounded core legs 1, which in a known manner to achieve a circumscribable by a circle as possible Well-filled cross-section layered from sheet metal stepped in different widths is. 2 is the tie rod usually executed as a flat iron, the lower and connects upper frame parts. Msn recognizes that this tie rod 2 the core especially in direction. Mechlamell @@@@@ jll ç no particular rigidity can give.

However, if according to the invention the protruding Ber @@@@ the widest Sheet metal group as at 3 and / or the schä: ste sheet group at 4 by U-shaped frofile girders VO :! three sides are tightly encompassed and these carriers are frictional and rigid with the frame, i.e. above and below with the yoke press iron or below with the Stand or chassis are connected, which is generally darch welding and If stiffening plates are attached, there can be sufficient stiffening and shifting the resonance free: can be achieved.

In Fig. 2 another embodiment of the invention is shown, in which a support 5 in the form of a double T is used as a leg stiffener. Here, the core sheets of the leg 1 are longitudinally divided in the middle and by both Sides layered or pushed into the openings of the double T-beam. as Stiffening ice. Of course, profiles with sharp-edged Corner training is used, the normal structural steel girders with rounded inside Corners would cause difficulties when layering the core sheets.

- patent claims - L e e

Claims (5)

Claims 1.) Laminated core for transformers made of sheet metal and the like., Consisting of at least one wound core leg and in the end regions overlaps layered yokes with lateral yoke press irons and with the lower ones Yoke press iron connected stand or chassis, characterized in that the Core legs (1) by enclosing profile beams (3,4,5), which form part of the stepped Cross-section of the core leg (1) from three sides, are stiffened, and that the ends of the profile carrier (3,4,5) with the yoke press iron and / or the frame are positively and rigidly connected. 2. Core according to claim 1, characterized in that the two-sided Overhangs of the widest laminated core of the core leg - (1) of U-shaped profiles (3) are encompassed on three sides (Fig.1). 3. Core according to claim 1, characterized in that the outer laminated cores it core leg 1) by U-shaped profiles (4) of corresponding dimensions of 1rei Pages are included (Fig.1. 4. Core according to claim 1, characterized in that the core leg cross section (1) across the plane of the sheet is divided into two halves and each half of each one side is inserted into the opening of a double-T-shaped profile (5) (Fig.2). 5. Core according to claim 1 to 4, characterized in that the core has a rectangular or a rectangular-like cross-section.