DE2048392A1 - Self-steaming electrical conductor - Google Patents

Description

DR. ING. B. HOFFMANN DIPL. ING. W. EITLE DR. RER. NAT. K. HOFFMANN

PATEHTANWLTE

D.8000 MÖNCHEN 81ARABELLASTRASSE 4 TELEPHONE (0811) 911087

Aluminum Company of America, Pittsburgh, Pa./USA

Self-damping electrical conductor

The invention relates to a self-damping electric Ladder for hanging between spaced supports, which consists of a hollow jacket and a core loosely arranged therein.

It is known that electrical lines and conductors, such as Overhead power lines, which are suspended between masts or supports, mainly cause constant mechanical vibrations as a result of the action of air currents moving over the cable or duct, the natural Period of oscillation of the line or harmonics thereof with the oscillation period caused by the air currents coincide. Such vibrations cause a continuously vibrating bending gemomerite on the support of the line,

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which can tire their metal on the support, whereby failure of the line at the column can result.

A well-known conduit structure designed to accommodate a To achieve high vibration damping, and of which the invention is an improvement, consists essentially from a core arranged in a hollow outer jacket, the inner diameter of the jacket being greater than that outer diameter of the core, so that an annular gap occurs between the two.

In use, the known line or ladder is placed between suitable support structures, i.e. masts or supports Applying different tension / weight ratios for the soul and the cloak, thereby increasing for the soul and the coat can give rise to different sags. In this way the top or bottom surface of the soul becomes physical pressed against the bottom or the top surface of the inside of the jacket, depending on whether the core or jacket is the larger Tension / weight ratio. 'The physical contact of the soul with the mantle occurs at a longitudinally extending Position between successive supports to support the ladder.

The inequality of the tension / weight ratios is after of the teaching of the prior art is required to achieve a higher degree of self-attenuation in the line. I.e. at a given frequency of the line oscillation results in the dissimilar The tension / weight ratios of the core and the jacket have different oscillation wavelengths, so that this is an interference result in the respective vertical movements. In this way it is achieved that mantle and soul are against each other

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strike and thereby the vibration energy through the attacks consume.

In the case of the known conductor, the pressure creates with which the soul and the mantle touch each other due to their unequal tension / weight ratios, a problem which the invention solves. For small oscillation amplitudes and for small oscillation frequencies, i.e. in the order of magnitude of 5 Hz, the inertial forces generated by the acceleration of the conductor are not large enough to maintain the contact force between the soul and the mantle to overcome. The soul and the cloak therefore do not come out of contact, so that they strike between the two is prevented. So the well-known conductor actually has a considerable acceleration threshold, which must be exceeded before its high degree of self-dampening comes into play.

Another known ladder structure for vibration damping is shown in US Pat. No. 3,204,021, which issued on Aug. 3, 1965 for H.W. Adams was granted. For the purpose of damping there is a random distribution of masses with a considerable Weight factor arranged along the length of the conductor is used. Such masses contribute significantly to the total weight of the Ladder, thereby increasing the weight that the ladder and the support structures must carry without the associated Advantages of a substantial reinforcement of the conductor or an increase in its current carrying capacity occur.

The aim of the invention is to overcome the disadvantages mentioned.

This object is achieved according to the invention in that means for varying the relative positions of the conductor in the Lines of action of the tensions in the mantle and the soul in

1 ■ 0 9 8 2 0 / 1.3 1.4

spaced intervals along the length of the conductor are arranged when the core and the jacket are suspended between the supports, the varying effects never correspondingly varying contact pressures between the jacket and the soul along the length of the conductor.

By means of the invention, the acceleration threshold value is thus eliminated or substantially reduced by the provision of varying values repetitive contact bridge between the core and the jacket along their length in that a part or both with a wavy or irregular shape along the Length of the conductor, the wavelength of the variations being a considerable length to be explained below Reasons. These varying contact pressures have correspondingly varying acceleration threshold values, where the areas of minimum pressure have minimum threshold values, so that only correspondingly small inertial forces and Amplitudes of the conductor oscillation are necessary for the relative movement between the soul and the mantle and so the soul-mantle stop begin to let. If the slightest movement or vibration occurs in the conductor, areas will be with can be activated at zero pressure. In this way, i.e. by immediately striking the core on the jacket when the conductor closes begins to vibrate, the ladder is made vibrationless before its metal works at the points of the ladder supports and this is weakened.

The ripple of the core or the jacket or both, to the varying repetitive contact pressure between the To evoke the core and the mantle can be provided by forcing a variation in the relative distance between the Lines of action of the soul and the mantle, whereby the lines of action are the locations of the points of attack of the tensions, which both the soul and the mantle must take up. Forcing

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Such a variation can be made by approximating a part or material of a predetermined thickness between the core and the jacket at spaced locations along the length of the Conductor between the ladder supports, or by providing an uneven distribution of tension among helically wound Metal strands that encompass the core or the jacket or both. In any case, the vibration damping will be with little or no increase in ladder weight achieved.

In the following the invention is described in detail with reference to the drawing. Show it:

Pig. 1 is a schematic view of a conductor constructed according to the invention and suspended between support structures;

Fig. 2 is a longitudinal sectional view of a preferred embodiment of the invention,

Fig. 3 is a sectional view along the line III-III in Fig. 2,

Fig. J- ¹ is a longitudinal sectional view of another embodiment of the invention,

Fig. 5 is an L ^r mgsschnittansicht a further embodiment of the invention,

6 shows a cross-sectional view of a further embodiment of the invention,

Ta and 7b are cross-sectional views of a core structure for illustration another embodiment of the invention,

8 shows a side view of the core according to FIG. 7,

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Pig. 9a to 9e are cross-sectional views of a core showing the changing positions of the strands forming the core arranged in a helical stroke, and

Fig. 10 is a schematic cross-sectional view of a self-damping Head, in which certain partial distances in the invention Heads are shown.

In Fig. 1, a conductor 10 is shown schematically, which with suitable support devices, not shown, between supports or masts 11 and 12 is suspended. The head. 10 consists in essentially of an outer shell 14 and an inner core 15i which with a space 16 between itself and the shell loosely in this is arranged. As already explained, the core and jacket between supports or masts 11 and 12 are with unequal proportions Tension / weight displaced so that the soul and the mantle are physically in contact with each other.

According to the invention, the core or the jacket or both have a wavy or corrugated shape in one direction along the ladder and in a repetitive manner between masts 11 and 12 as shown in Figure 1. Touch this way Soul and mantle each other with a force or pressure which changes in a similar repetitive manner when the Core and mantle between the masts with unequal tension / weight ratios be relocated. The ripple is caused by changing the relative action lines or the points of application of tension in the soul and mantle, and this is achieved by making cyclical changes in the relative Displacement of the soul and mantle can be enforced in a variety of ways, as referred to below on the various embodiments of the invention will be explained.

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If the soul 15 and the jacket 14 have the same proportions Suspended tension / weight, the soul would be within of the coat independent of the coat and not touching it. The soul and the cloak were seen from the side appear as congruent chain lines with no points of physical contact, even if one or both parts have a wavy shape would have. A slight decrease in the tension of the soul I5 causes however, that it falls down in the jacket 14 until it hits the inner floor surface of the jacket as in Pig. I shown rests, the contact between the two takes place at the lowest points of depressions 17 of the waves of the soul in one embodiment, where the soul is the wavy part. The core has tips 18 between the lower points, which are at a distance of about twice the amplitude of the waves of the soul measured between the bottom of the soul and the bottom of the inner surface of the jacket.

If the tension in the soul is further reduced, the downward pressure of the soul on the jacket 14 is increased. This increased pressure comes first all lower contact points or depressions 17 · If the tension of the core is further reduced, the slack increases the core between the contact points, so that the distance between the shaft tips of the core is reduced, and the contact areas the depressions 17 between the core and the jacket are widened in the longitudinal direction of the conductor.

If the tension of soul I5 is further reduced, the distance between the core and the jacket 14 will eventually disappear at the original tips 18 of the shaft. At the moment of disappearance and before, the pressure is between of the soul and the mantle at these points. On both sides of these points the pressure is

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gradually increase with distance and a maximum of the original Reach steles of the depressions 17. With this pressure distribution in the conductor 10, there is essentially no acceleration threshold on, which must be exceeded for self-damping to occur. Areas of pressure will be zero at The slightest degree of ladder movement or vibration can be brought into a self-damping stop. Next can the parts of the soul, which are not in contact with the jacket, vibrate freely with the conductor oscillation and thereby the impact effect increase the soul against the mantle.

It will be understood that mere ripple or change in contact pressure is not enough to solve the threshold problem overcome. Most metallic surfaces have a certain Degree of roughness, so that the contact between the metallic surfaces occurs at a variety of roughnesses, wherein the contact pressure at the different roughness is different. Next make helically twisted conductors and using the usual round wires, roughly wavy profile ^ e As a result of this helical stroke. An acceleration threshold exists despite these undulating conditions.

To be effective for self-damping purposes, the frequency is allowed to of the changes in pressure along the conductor 10 should not be excessive, i.e. the areas of the depressions 1? and tips 18 with high and low pressure or zero pressure must be relatively large and so separated from each other. The reason for this has to do with with the relationship between the speed of oscillation of the conductor 10 as a single unit and the relative speed of the stop between its subcomponents, namely the core 15 and the jacket 14. The vibration speed of conductor 10 controls the speed at which

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-Q-

the vibration energy is communicated to the conductor. The relative speed of the stop controls the speed of the Energy consumption as a result of the attack. The goal is that the rate of energy consumption is greater than that Speed., With which energy is supplied by the wind, both energies increasing rapidly with their associated speed. It is therefore desirable that the ratio the speed of the stop to the speed of the conductor oscillation is as great as possible.

The relationship between the distances between points of high and low contact pressure on the sinks 17 and supports 18 between soul and mantle and the ability of the soul and the mantle to strike against each other can be explained as follows be: When the vibration of the conductor 10 accelerations and causes inertial forces which are sufficiently great to keep the core and the jacket in the region of the tips 18 low To separate contact pressure or pressure zero, but not the adjacent areas of the depressions 17 of higher contact pressure, so will the size achieved by the separation during each oscillation period can be greatly influenced by the dimensions of the distance of the areas of higher pressure on each side of the areas of low pressure Pressure or zero pressure. That is, if the areas of higher pressure are too close to those of lower pressure, the Stiffness of the core and shell material and the degree of curvature, which these assume as a result of their tensions and masses, no great separations of the soul and the mantle in the areas low pressure too. With small areas and short distances Because of the separation at the tips, only small stroke speeds are achieved »The distances between the points high and low contact pressures must therefore, as mentioned above, be relatively large.

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2348392

The effective solution to the threshold problem is then to combine the soul and the mantle or both with a physical one To provide ripple in which each wave has a considerable wavelength, i.e. a wavelength of the order of magnitude of meters and maybe as tall as 15 meters, being the size the wavelength for a given arrangement or a corresponding installation of the various conductor parameters and the Environmental conditions depends.

When the conductor 10 is laid on site, the vertical components of the tension bear along the entire length Length of the ladder occur, the total ladder weight against gravity. A well-known mathematical derivation leads to the following equation expressing this phenomenon:

In this equation is

T = the horizontal component of the total voltage of conductor 10,

w = the total weight per unit length of the conductor, χ = a horizontal length component along the line,

y = the height of the conductor above a horizontal reference plane.

The solution to this equation gives y as a function of x, and the shape of this function is a chain line on the graph. The function describes the shape of the curve, in which the ladder hangs. However, the function is precisely related and only to the location of the points of application along which the tension acts in the conductor. This place usually coincides with the geometric axis of the conductor, but this is not always the case, as will be seen below.

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For common spans of the conductor, the above equation without .essential errors in the to be drawn from it Conclusion can be approximated by the equation:

_T ix

άχΤ

This equation can also be applied individually to the soul I5 and the mantle 14 can be applied. When applied to the soul and the mantle, an additional term "p" is introduced, to account for the contact pressure between the two. The equations for the soul and the mantle are as followsί 2 · 2

Tc ^ -p + W ₀ + ρ = 0 and Tm ^ -ψ- + W - ρ = 0

where Tc and Tm are the horizontal components of the stresses in the core and in the jacket, respectively, and W _Q and W are their respective weights per unit length. There there? Pressure ρ between them results from one part bearing part of the weight of the other, an expression equal to that amount of weight is added to one equation and subtracted from the other. Here ρ is measured in units of force per unit length along the conductor 10.

The basic procedures for introducing variations in ρ with length along the conductor can be found from these equations can be distinguished. For example, if one considers the equation for the soul, then in order to vary ρ T, W or

2 2 CC

d yc / dx can be varied individually or in a combination. Variations of T can be practically introduced, for example, by initially routing the conductor with the same ratio Tension / weight in soul and cloak, and then loosening of the soul so that it slips back into the cloak. At the end of Soul that has been released, the tension will then be zero,

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while the tension at the opposite end is considerable Will have value due to the friction of the soul sliding into the jacket. The soul and the mantle can then be brought into engagement with one another by pressure clamps at various intermediate points in order to eliminate the inequality to prevent the tension.

Variations in weight W can be practically caused e.g. by intermittent Applying a heavy top coat to the core or sheath can be introduced as mentioned in the above U.S. Patent 3,024,021 is shown.

However, there are provision for variations in the contact pressure ρ by changing the tension T or T or the weight W or W

C ΠΊ C ITl

no economic solutions to the problem of reduction the threshold value of the acceleration which is necessary for the soul and the mantle to produce an immediate self-damping to separate. E.g. the clamping of the core and the jacket on the construction site is a busy and time consuming one Effort and such an expensive process. Similarly, adding spaced weights to a pipe is unusual expensive as it usually requires interruptions in the twisting process, which otherwise is a continuous process represents. Furthermore, weights that are spaced apart from one another usually add to the total weight of the conduit without affecting the others Advantages of increasing the strength or ampacity of the line occur, since such weights are only intermittent are arranged along the length of the conduit.

As a result of the drawbacks and difficulties associated with varying the parameters of stress or weight along the conductor 10 are connected, the invention is thus concerned with the variation of the curvature of the core or the jacket, i.

? PPP
d yc / dx or d ym / dx.

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The method and apparatus for providing these variations in curvature is provided by forcing a varying separation of the soul and the mantle, as in above with reference to FIG. The actual structure for forcing these variations is shown in Figures 2 through 10, wherein it is kept in mind that the differential equations actually represent the lines of action or points of attack of the tensions to which the soul and the mantle are subjected are.

In Fig. 2, variations in the curvature of the core 15 and the shell 14 is provided by annular reduced diameter portions 20 formed on the inner surface of the shell are, and are arranged at a considerable distance from one another in the longitudinal direction of the shell. Lift such parts Sections of the core above the bottom surface of the jacket so that the core has points with peaks 18 away from depressions 17, which touch the jacket as described above in connection with FIG. In this way the soul becomes wavy made, and the relative points of application of tension in the soul and in the cloak are thereby repeated by repetitive varying distances along the conductor 10 between its support structures or masts 11 and 12 separately (Fig. 1).

The reduced diameter parts 20 can be of various types Manner and by various means. A simple process of air production of parts with reduced Diameter in a sheath of twisted wires would be after the innermost layer of strands 22 of the sheath to bend inside, as shown in the cross-sectional view in Fig. J5 is shown.

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20A8392

Pig. 4 shows another embodiment of the invention at which the core 15 has spacers 24, which on the and are attached around the soul at spaced locations along its length. The spacers are preferably made of one Material with a negligible weight factor, e.g. made of a suitable plastic. The shape of the spacers may be ring-shaped or cylindrical, and they may, for example, take the form of ring-shaped lumps which when wrapped of the soul with a ribbon.

The spacers 24 have the same function as the parts 20 of reduced diameter of the shell 14 and serve to this, the places of the tips 18 of the core from the bottom surface of the mantle and in the length of the depressions 17 in contact with away from the floor area.

In addition to the spacers described so far, other spacers can also be used to provide spacing between the jacket and to manufacture the core in a repetitive, varying manner in the longitudinal direction of the conductor 10. E.g. the soul can be covered with a continuous cover of material 25, which has a variable thickness along the core as shown in Fig. has shown. In this figure, the line of action of tension in the soul is congruent by a dashed line shown with the axis of the soul.

Fig. 6 shows in cross section an elliptical spacer in the form of a sleeve of material 25A, which in similar As in FIG. 5, it is arranged around the core 15. However, a wavy line of action for the soul is created by twisting the core provided during their twisting, so that the irregular elliptical cross-section of the shell extends along the Length of the soul in the mantle turns. In this way, the relative positions of the points of attack in the soul and coat also change the rotated position of the elliptical shell.

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Other spacing means can be used in place of or in combination used with the spacers shown in Figs be around the lines of action of the soul and the mantle in a repetitive varying manner along the length to separate the soul.

In a way to be described here, the soul or the jacket or both can be made wavy without the use of the spacers described above. This can be achieved by creating an unequal un eccentric stress distribution between the helically wound Wire strands 26 (Fig. 7 to 9), which the soul or the Form coat. In Fig. 7 to 9 "is for the sake of clarity Only the Seeie-15- is shown. The uneven stress distribution can be provided by twisting the core or the sheath with groups of tension-free and taut strands, or by using groups of wires with different stress-strain properties, i.e. different tempering, Alloy or hardness properties. In Fig. 7 and 9, for the purpose of illustration, the more tensioned strands with a Plus sign (+). If the soul or the jacket is tensioned on the construction site, the relatively tension-free ones take it or soften strands with less tension than the stretched or harder metal strands. This causes the point of attack the tension in the whole soul or the jacket of the strands with the lower tension away and to the strands is shifted towards the greater tension. The line of action the tension thus moves away from the geometrical axis or the center of the soul or the jacket to the strands with it higher voltage (+). If the wire strands 26 are applied to the core with a helical blow, the location of the geometric center follows a helix around the line of action. And there the line of action as described above takes the form of a chain line, the winds

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geometric axis around the catenary, resulting in a ripple the core or the jacket as shown in Fig. 8, results.

It should be noted that the use of unevenly tensioned, helically laid strands results in a waviness, in which each wave has a wavelength equal to the lay length of the strands with the greater tension, one lay the Path of a complete revolution of the helical line formed by a helically laid strand. If currently used lay lengths are used, this is the lay length too short to cover the areas of the troughs 17 and peaks 18 high and low. Pressure between the core and the cladding occurs to separate sufficiently in the longitudinal direction. A wavelength of ripple that is greater than that Length of lay, however, can be achieved through the "use of two layers 27 and 28 and laid on helically Strands 26 with unevenly tensioned strands in both layers, as shown in Fig. 7, and the lay length of the the two layers is slightly different. The ripple of the whole soul or madbel would be the superposition of the ripples be which with unevenly tensioned strands only in the inner layer 28 of the two layers (case 1) and only in the outer Layer 27 of the two layers (-case 2) would occur. So would in in each case the geometrical axis of the core or of the jacket follows the helical line around the line of action of the tension, where the helix would have a wavelength of the beat of the inner layer in case 1 and of the outer layer in case 2.

If the inner and outer layers 28 and 27 of the wire strands 26 had the same length and lay direction, the Superposition of the ripples of each layer lead to an increased or decreased ripple depending on whether the Higher tension strands of the two layers together; en on the

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same side of the soul as in Fig. a or on the opposite side Page as in Fig. 7b would be. Any situation can be achieved and the resulting degree of waviness would not change along the length of the soul because the relative alignment of the inner and outer groups is higher taut strands would not change due to the same lay length.

If the lay lengths are made somewhat different, however, the relative orientation of the inner and outer layers 27 and 28 changes continuously along the length of the core 15 and results in areas JO with enlargement alternating with areas 29 with reduction in waviness, as shown in FIG. 8 is shown. The wave length of the waviness is equal to the mean of the lay lengths of the two (inner and outer) layers. The wavelength of the alternation between enlargement and reduction, ie the amplitude of the waviness, is greater than the wavelength of the waviness, and can be given by the formula 1 2.

V ^L i

where L ₁ and Lp are the lay lengths of the inner and outer layers 28 and 27, respectively. The wavelength of change in ripple amplitude can be easily controlled over a wide range by appropriately selecting L ^ and L ^.

In the illustration above, the lay directions were both layers were the same, and this led to the geometric The axis of the soul followed a helical path around the line of action. The directions of impact can on the other hand be opposite. Consider the case where this occurs and where the lay lengths are equal. Fig. 9 shows a series of cross-sections of a core constructed in this way, the cross-sections at intervals of along a quarter of the helical lay length

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are taken from the soul. The series shows how the strands with higher tension (+) move around the geometric axis of the soul move at a distance along the soul. The series of views further shows that the direction of movement for the two positions 27 and 28 is reversed, resulting in different relative Alignments of the two groups of higher tension (+) strands at different points along the core result. The change in relative alignment is fast and goes through a full cycle in one lay length.

From Fig. 9 it is clear that the superposition of cases 1 and ■ 2 results in a polarization of the ripple in this case. While cases 1 and 2 each show helical waviness, They reinforce each other in the superposition in the vertical direction and tend to each other in the horizontal direction to cancel. The cancellation may not be complete, but the difference in the vertical and horizontal amplitudes is the waviness shows the core 15 with a degree of vertical polarization in its waviness. If the soul were with the inner ones and outer groups of strands of higher tension adjoining each other on the sides of the core rather than on the top and If the lower part of the soul had been built up, a horizontal polarization would have resulted.

Since the beat lengths of the two layers 27 and 28 were the same in the above illustration, the direction of polarization does not change with the position along the core. However, if the lay lengths of the two layers are slightly different, the plane of polarization will rotate with the longitudinal position along the core 15, with a complete rotation over the distance 1 2 from

L ₂ -L ₁

to be led. Seen from the side, a soul will show the same profile as the soul in both directions are the same. It is shown in FIG

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Shape, with alternating areas J5O and 29 with waviness high and low amplitude occur in the vertical plane.

In use, the areas 50 of undulation become higher Amplitude the areas of the depressions 17 high pressure between core and jacket and the areas 29 of low amplitude the areas of the peaks 18 become low pressure.

The use of groups of strands of higher tension in two layers to achieve changes in ripple with a relatively long wavelength can be carried out in connection with the cladding as well as with the soul. Can continue a long wavelength in the change in pressure between the core and the jacket can be achieved with one of the layers 27 or 28 in the soul and the other in the cloak. In addition, what has been achieved with two layers can also be achieved with three or more layers can be achieved in order to obtain either the same type of ripple or those types where the amplitudes and polarizations are modulated in more complicated ways. The practical result, however, is the same that changes are generated in the contact pressure between the core and the jacket.

The above examples show setups that require a change force in the relative position of the lines of action of the soul and the jacket along the conductor 10. In any case it was obtained by either liner of a composition changing Dimensions between the two lines of action or by providing strands of different tension in the wire strands the soul or the mantle. The function of such structures can be represented by subdividing the separation of the lines of action in the following partial distances.

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1. The distance between the line of action and the geometric center of the soul.

2. The distance between the geometric center of the soul and the surface which is in contact with the mantle.

5 · The distance between the surface of the mantle, which in Contact is with the soul, and the geometric center of the mantle.

4. The distance between the geometric center and the line of action of the coat.

These partial distances are shown in the cross-sectional view in Fig. 10 shown where a the point of the line of action of the soul, b the geometric center of the soul, c the point of contact between Soul and mantle, d is the geometric center of the mantle and e is the location of the line of action of the mantle.

The cross section shown in Fig. 10 is for purposes only shown, while the structure of the soul and the mantle would be more complex in practice. The geometric The middle of the soul and the matel will in most cases be somewhat arbitrary, since in many structures the axial Symmetry will be absent. In these cases, each reference point which in relation to the geometry of the cross-section of the corresponding Part (core or jacket) is fixed, can be used as geometric Mfcte for the present purposes.

Examination of Figures 1 through 10 shows that each of these sub-spacings can be varied to accommodate variations in the relative positions of the lines of action of the soul 15 and the jacket l'4 to reach. The partial distance 1 was varied in FIGS. 7 and 9, the partial distance 2 was varied in FIGS. 2 to 6, and the

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Partial distances j5 and 4 were varied by applying the principles these figures on the mantle.

So the basic construction of the invention is a Loose-soul ladder 10 which is caused to have one or several of the above partial distances, which separate the line of action of core and jacket, along the length of the conductor vary by varying the structure that defines the partial spacing. The distance over which the variation in generally repeated along the conductor, must be large, so that a substantial separation of the soul and the sheath in Areas of low pressure can be reached when the conductor begins to vibrate. In this way, a stop can high speed between the soul and the mantle in these areas of low pressure can be achieved to the To consume vibration energy and thereby to bring about a quick and effective self-damping in the conductor.

The self-damping capabilities of the conductor according to the invention have been demonstrated in tests, which for comparison these skills with those of a well-known leader with looser Core, i.e. with a conductor without cyclical variations in the contact pressures between the core and the jacket became. In the experiments, a span of the suspended conductor was externally excited or vibrated by the Power of a vibration motor, and the rate of decrease in vibration became after removing the exciting force measured. In this type of experiment the important parameter is the logarithmic decrement, which is the natural Is the logarithm of the ratio of the amplitudes of two consecutive oscillation cycles. To a satisfactory To achieve self-damping on the ladders in question, the logarithmic decrement must be greater than 0.005. If it exceeds this value, the energy

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Consumption in the conductor is the speed with which energy can be absorbed by the wind in order to achieve the conductor oscillation to support.

Two series of tests were carried out: one on one known conductor, and one on the same conductor with spacers 24 such as in connection with Pig. 4 described. The logarithmic decrement was made at different vibrational frequencies with the conductor under different voltages and measured with different divisions of the tension between the soul and the mantle. The following numbers are some Examples of the test results.

For a conductor without means for cyclically varying the contact pressure between the core and the jacket with a conductor voltage of about 2270 kg, of which about 500 kg were on the core, and with a frequency of about 15 1/2 Hz the logarithmic decrement was 0.016 for the free oscillation amplitude the oscillation over 1.524 mm peak to peak. This corresponds to a maximum acceleration of 0.73 g · For lower vibration amplitudes and thus accelerations the logarithmic decrement was 0.002. An amplitude of 1.524 mm is required before the self-damping is sufficient to prevent the amplitude from increasing further.

When the conductor was provided with spacers in a manner similar to Fig. 4 and all other parameters the Staying the same as above, the logarithmic decrement was 0.012 for all vibration amplitudes down to one free oscillation amplitude of 1.524 mm peak to peak, which corresponds to a peak acceleration of about 0.08 g. So is the self-damping in the invention is effective at significantly lower oscillation amplitudes.

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At a lower test frequency of about 7 Hz and the The same voltage and division of the voltage as above, the known conductor has a logarithmic decrement of 0.01 ^ 3 for Shrinkage amplitudes over 3.23 mm tip to tip, and a logarithmic decrement of 0.0023 for amplitudes below this value of 3.23 mm. This corresponds to a maximum acceleration of about 0.32 g. At the oscillation frequency of 7 Hz, the conductor according to the invention had an Ipgarithmisch.es decrement of 0.064 for amplitudes down to about 0.305 mm peak Top. Again the amplitude became the self-damping at which becomes effective, substantially reduced by the use of spacers 24.

From the foregoing description it can be seen that the invention provides new means for substantial enlargement the self-dampening abilities of a leader with a loose soul were created.

This is achieved more considerably by providing a waviness Wavelength in the core or the cladding or both of the conductor, so that there are alternating areas of high and low contact pressure or zero pressure between the core and the jacket along the conductor in a repetitive manner between the Ladder supporting structures or masts occur. In this way, have the parts of the soul or the mantle with the base Contact pressure or pressure zero similar to low acceleration thresholds, creating an immediate relative movement is provided between the core and the jacket in order to cause an immediate stop process between the two.

109820 / 13U

Claims (1)

2Ü48392 - 24 claims ti. Self-damping electrical conductor to hang between spaced supports, which consists of a hollow jacket and a core loosely arranged therein, characterized in that in the conductor (10) devices for varying the relative positions of the lines of action of the tensions in the jacket (14) and the core (.5) in spaced apart Intervals are arranged along the length of the conductor when the core (15) and the jacket (14) are between the supports (1, 2) are suspended, the varying lines of action correspondingly varying contact pressures between the jacket (14) and the core (I5) in the longitudinal direction along the conductor (10) result. 2. A ladder according to claim 1, characterized in that the means for varying the relative positions of the lines of action in the jacket (14) and the core (I5) parts (20) with a reduced inner diameter of the jacket (l4) along the Include the length of the conductor (10) at spaced apart locations. 5. Ladder according to claim 1, characterized in that that the devices for varying the relative positions of the lines of action in the jacket (14) and the core (I5) around the core (15) arranged spacers (24) comprise at spaced apart locations along the length of the conductor (10). 4. Head according to one of claims 1 to J>, characterized in that the core (15) consists of a plurality of helically wound strands of material which extend generally in one direction along the conductor (10), and that the devices in the conductor (10) for varying the relative positions of the lines of action of the tension in the jacket (14) and the core (15) comprise means for eccentrically distributing the tension in the plurality of strands. 109820 / 13U -25- - 25 - 5. Ladder according to claim 4, characterized in that the that eccentric distribution of tension through a group of neighboring Strands (27, 28) from the plurality of strands with a strain-tension property different from that of the remaining strands of the plurality of strands is provided is. 6. Head according to one of claims 1 to 3, characterized in that g e k e η η shows that the core (15) has at least two layers (27, 28) helically wound strands of material with uneven distribution of tension between the strands in both layers comprises, the lay length of the strands in one layer (27) being different from that of the strands in the other layer (28). 7. Ladder according to one of the preceding claims, characterized in that that the means in the conductor (10) for varying the distance between the core (I5) and the jacket (14) along the length of the conductor (10) at smaller intervals are arranged at a distance from one another as the supports (11, 12) between which the ladder (10) is suspended, whereby the relative lines of tension in the jacket (14) and the core (15) are cyclical along the length of the conductor (10) vary between the supports (11, 12). 8. A ladder according to claim 7> characterized in that that the means in the conductor (10) for varying the distance between the jacket (14) and the core (I5) have an between these arranged spacers (25, 25A) comprise, which extends in the longitudinal direction of the conductor (10) and eccentrically with respect to the conductor (10), wherein the eccentricity of the spacer (25, 25A) with the lengthwise position of the The spacer rotates around the soul (15). -26- 1098207 13U 9 · Ladder according to claim 7 or 8, characterized in that the devices in the ladder for varying of the distance between dem.Mantel (14) and the core a sheath of material (25) around the core (15) between the jacket (14) and the core (15) arranged comprise, the shell a cyclically varying thickness along the length of the soul (15). 10. A ladder according to claim 7 or 8, characterized in that the means in the ladder for varying of the distance between the jacket (14) and the core (15) comprise a sheath of material (25A) arranged on the core (15), obei the shell has an irregular cross-section, which is related to the lengthwise position of the shell along the core (15) the soul turns. 10 9820/1314 Lee on the back