JPS5953688B2 - Earthquake resistant transformer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an earthquake-resistant transformer that increases the natural frequency of a dry type transformer, a molded transformer, or the like.

Generally, the transformer body of a dry type transformer has a winding 1 wound around an iron core 2, as shown in Figs. The lower end is clamped and fixed by the upper tightening bolt 7, and the lower end is clamped from both sides by the lower clamping tool 3 having a U-shaped cross section.
It is fixed and formed by

An insulating plate 6 is disposed between the lower surface of the lower fastener 3 and the iron core 2 and the upper surface of the base metal fitting 5 fixed to the floor 10 via foundation bolts 19, and the lower fastener 3 is fixed to the base. It is fixed onto the base metal fitting 5 via bolts 9. Note that the insulating plate 6 is provided so that the iron core 2 will not be short-circuited between the laminated layers due to the base metal fitting 5. In such a transformer, if seismic waves attack the floor 10,
The transformer body 17 exhibits response characteristics as shown in FIGS. 2 and 3. Here, the natural frequency of the transformer body 17 is low,
Let us consider the case of vibration in the direction of the arrow, which is likely to resonate with seismic waves. In general, a transformer is indicated by a simple Seder.
The natural frequency f of the vibration system in the figure. (H,) is expressed by equation (1). f0=Left□ (□) Flattening is the spring constant of the vibration system, which is a combination of the spring constant of the transformer core, the rotational spring constant Jθ and the displacement spring constant kH of the transformer mounting part. It is what it is.

Of these, the spring constant and kH are determined by the cross-sectional area of the transformer core, the tightening of the fasteners, etc., while the rotational spring constant Jθ is determined by the elasticity of the lower fastener 3 and the insulating plate 6, and the natural vibration It has a big impact on numbers. In Figure 4, the horizontal axis shows the stiffness (rotational spring constant) Jθ of the lower root of the iron core, and the vertical axis shows the natural frequency (H2). As shown in curve A, the larger the rotational spring constant Jθ, the greater the natural vibration of the vibration system. The numbers will be high.

The frequency components of seismic waves are mostly 0.5 to 10H.
, so in order to prevent the transformer body 17 from resonating due to seismic waves, it is necessary to increase the natural frequency by increasing the spring constant K as much as possible to 10H2 or more. In this case, as shown in an exaggerated manner in Figure 3,
In the conventional case, since an insulating plate 6 made of an elastic material is interposed below the core, it is difficult to increase the spring constant Jθ due to this compressive deformation. Furthermore, since only the lower end surface of the lower fastener 3 is tightened and fixed to the base metal fitting 5 by the base fixing bolt 9, the lower fastener 3 is tilted as a whole, creating a deformation gap a, which reduces the spring constant Jθ. It is kept to a small value. SUMMARY OF THE INVENTION An object of the present invention is to provide an earthquake-resistant transformer that eliminates the above-mentioned drawbacks and improves seismic properties by increasing the spring constant of the transformer body and preventing resonance with seismic waves.

The seismic transformer of the present invention has a winding wound around an iron core, upper and lower parts of the core are respectively fixed via upper and lower fasteners, and the lower fastener is supported and fixed on the floor via a base metal fitting, A connecting plate fixed to the end face of the lower fastener, a stiffening metal fitting having an L-shaped cross section and one side of the L-shape fixing the connecting plate of the lower fastener on both sides sandwiching the iron core, and a stiffening metal fitting fixed to the floor. An auxiliary base is provided for fixing the other side of the L-shape of the stiffening metal fitting.

An embodiment of the seismic transformer of the present invention will be described below, with the same parts as those of the conventional one indicated by the same reference numerals, and explanations of the same parts omitted.
This will be explained using figures.

A connecting plate 20 for fixing one surface 22 of a stiffening metal fitting 18 having an L-shaped cross section is fixed to an end surface of the U-shaped lower fastener 3. The stiffening fitting 18 is inserted into a fastening fitting connecting hole 11 provided in the stiffening fitting 18 and a hole provided in connecting plates 20, 20 of the lower fastening fittings 3, 3, which sandwich the iron core 2 from both sides. Connecting plate 20 via fastener connecting bolt 14,
It is fixed at 20. The other side 23 of the L-shaped stiffening fixture 18 is fixed to a U-shaped auxiliary base 16 fixed to the floor 10 via foundation bolts 19 via base connection bolts 15 inserted into the base connection holes 12. . Insulating plate 6
In order to prevent a short circuit between the layers of the iron core 2 due to the base metal fitting 5, the lower end portion of the iron core 2 is contacted, but it is not interposed between the base metal fitting 5 and the lower fastener 3.
Reference numeral 13 denotes a stay that connects one side 22 and 23 to reinforce the entire structure.

Since the seismic transformer of this embodiment is configured in this manner, the lower fasteners 3 on both sides of the iron core 2 are restrained from deformation by the stiffening metal fittings 18 even when subjected to seismic waves. Insulating plate 6
The influence of elastic deformation caused by this is also eliminated, and the rotational spring constant Jθ can be increased. Therefore, in FIG. 4, the natural frequency F2 can be increased to f1. Also, the fifth
The figure shows the response characteristics of the transformer with the excitation frequency on the horizontal axis and the response characteristics on the vertical axis.In contrast to the conventional curve B, the curve C of this example shows the natural frequency in the range of seismic waves. Frequency F
8 (H2) and shift its position, displacement and deformation of the transformer main body 17 can be suppressed to a small value, and earthquake resistance can be improved. As described above, the earthquake-resistant transformer of the present invention has the effect of improving earthquake resistance by increasing the spring constant of the transformer body and preventing resonance with earthquake waves.

[Brief explanation of the drawing]

Figure 1 is a front view of a conventional dry transformer, Figure 2 is a side view of Figure 1, Figure 3 is an explanatory diagram of vibration during an earthquake in Figure 2, and Figure 4 is a rotating spring of the transformer. 5 is a vibration model diagram of a transformer, FIG. 6 is a side view of an embodiment of the earthquake-resistant transformer of the present invention, and FIG. 7 is a part of FIG. 6. 8 is a perspective view of the stiffening fitting shown in FIG. 6, and FIG. 9 is an explanatory diagram of the relationship between the response magnification and the excitation frequency of the transformer shown in FIG. 6. 1...Winding, 2...Iron core, 3...
...Lower fastener, 5...Base metal fitting, 6...
...Insulating plate, 16...Auxiliary base, 17...
...Transformer body, 18...Stiffening metal fittings, 20
・・・・・・Connection plate.

Claims (1)

[Claims] 1. An earthquake-resistant device in which a winding is wound around an iron core, the upper and lower parts of the core are respectively fixed via upper and lower fasteners, and the lower fasteners are supported and fixed on the floor via a base metal fitting. In the transformer, a connecting plate fixed to an end face of the lower fastener;
A stiffening metal fitting having an L-shaped cross section and one side of the L-shape fixing the connecting plates of the lower fasteners on both sides sandwiching the iron core, and a stiffening metal fitting fixed on the floor and having the other L-shaped side of the stiffening metal fitting fixed on the floor. An earthquake-resistant transformer characterized by being provided with an auxiliary base for fixation. 2. The earthquake-resistant transformer according to claim 1, wherein the lower fastener is directly fixed to the base metal fitting, and an insulating plate for preventing short circuit between the laminated cores is provided only at the lower part of the core.