CN104364855A - Cable made of litz wires - Google Patents

Abstract

The invention relates to an electric conductor (C) which comprises a plurality of strands (2) extending between two ends, each one of the strands (2) having on the surface thereof a layer of electrical insulator (6), the strands (2) being electrically connected in parallel at each end of the electric conductor (C), characterized in that the strands (2) are arranged around at least one tube (1), made of an electrically insulating material, forming a core, with a coolant flowing through the tube (1).

Description

Twisted wire cable

Technical field

The present invention relates to a kind of electric conductor with the many strands extended between two ends, every root strand has electric insulation layer in its surface, and strand is electrically connected in parallel each end in electric conductor.The electric conductor of the type is commonly called twisted wire cable.

More specifically, the frequency of utilization of conductor involved in the present invention is included between 1kHz and 500kHz.

Background technology

Owing to being called as the phenomenon of kelvin effect, on upper frequency, electric current has only can in the trend of conductive surface circulation.Therefore the conductor skin of On current is called as skin depth.This phenomenon causes outside the circulation of electric current and is connected on conductor periphery, reduces useful section thus, which results in higher resistance and adds loss.

The use that the diameter of every root strand is less than the twisted wire cable of the skin depth of the material used in frequency of utilization makes it possible to reduce ohmic loss.

Regrettably, especially when high-frequency current, the electrical insulating property of different strand does not allow the remarkable rising can avoiding conductor temperature.

Summary of the invention

Object of the present invention especially provides a kind of conductor, permits using high-frequency, minimizes it simultaneously and heats up.The conductor allowing to use high current or constant current is dispersed in convenient loss, can not heat adjacent member.

According to the present invention, electric conductor has many strands, many strands extend between two terminals, every root strand has electric insulation layer in its surface, strand is electrically connected in parallel to each terminal of electric conductor, it is characterized in that, described strand is set at least one pipe around the formation core implemented with electrical insulating material, cryogenic fluid flows through described pipe, and the outer surface of strand and described pipe is had and is greater than the coefficient of heat conduction of 0.2W/mK and the lotion of electric insulation floods, to ensure the good transfer of heat between strand and pipe.

Every root strand can be implemented to be wound around completely at least one times around pipe between two of a conductor end.

Advantageously, the coefficient of heat conduction of the lotion of described electric insulation is greater than 0.5W/mK.

According to ISO 868 standard, described lotion can have the shore hardness A being less than 75.

Described electric conductor can comprise oversheath.

Described pipe can present ring grain shape or spiral geometry.

The invention still further relates to the purposes at the frequency place between 1kHz and 500kHz of electric conductor as defined above.

Accompanying drawing explanation

With reference to accompanying drawing, by the following detailed description to nonrestrictive particularly preferably execution mode, other features and advantages of the present invention will become clear.In the drawings:

Fig. 1 is the perspective view according to end conductor of the present invention,

Fig. 2 is the cross sectional view of the conductor of Fig. 1,

Fig. 3 is the longitudinal section view of the conductor of Fig. 1,

Fig. 4 is the end view of three kinds of execution modes according to pipe of the present invention to 6,

Fig. 7 to 9 be Fig. 4 to 6 the longitudinal section view of execution mode,

Figure 10 is the longitudinal section view of other three kinds of execution modes according to pipe of the present invention to 12,

Figure 13 is the end view of the another kind of execution mode according to pipe of the present invention,

Figure 14 is the longitudinal section view of the execution mode of Figure 13, and

Figure 15 is the longitudinal section view of other four kinds of execution modes according to pipe of the present invention to 18.

Embodiment

Referring to figs. 1 through 3, as seen according to conductor C of the present invention.The fuse of conductor C is made up of pipe 1, and the cooled fluid of pipe 1 flows through.Fluid or gas can be water, oil or other heat transport fluid any.

Pipe 1 is realized by electric insulating copolymer, to avoid inducing Foucault (Foucault) electric current in pipe 1 on upper frequency.In order to provide necessary flexibility to conductor C, pipe 1 presents helical form profile.

Strand 2 is longitudinally settled by around pipe 1.Strand 2 is reorganized to form wire harness and every root strand 2 is covered by electric insulation layer 6.Do not need in theory to add ancillary insulator, this is because strand is isolated between wire harness.Every root strand 2 has segregate many cables.

In fact, can isolate strand to improve mechanical strength and its manipulation of wire harness and to damage the enamel of isolating strand for avoiding, enamel can phase mutual friction when two strands contact.

The wire harness of strand is distributed in the outside of pipe 1 around whole pipe 1, and becomes layer with single screw.

Especially use the strand 2 be knitted on pipe 1 and/or multilayer strand, the execution mode substituted can be carried out.

In addition, strand 2 is recombinated to form wire harness not necessarily.Possible alternative is directly distributed in around pipe 1 by strand.

Strand 2 is electrically connected on outside conductor in parallel.Every root strand 2 has complete winding at least one times between the splice terminal at conductor two ends.This makes it possible to guarantee and switches, and this is conducive to the current balance type in the strand on upper frequency.

The length of conductor depends on that it is applied.

The outer surface of pipe 1 and strand 2 is impregnated with the product being called heat-conducting cream 4, to ensure heat transfer good between strand 2 and pipe 1, to be conducive to carrying out heat transfer from strand 2 to the cryogenic fluid be circulated in pipe 1.

Heat-conducting cream 4 is for being filled in hollow bulb, the software product in gap between strand 2 and pipe 1 of pipe.With shore hardness A lower and preferably shore hardness A be less than 75 elastomer produce heat-conducting cream, to mate the shape of strand 2 and pipe 1 best, the distortion that simultaneous adaptation conductor C may bear.Heat-conducting cream or electric insulation, this is conducive to the electric insulation of different strand 2.

The thermal conductivity coefficient that heat-conducting cream has is greater than 0.2W/mK and is preferably more than 0.5W/mK.It is possible for running with less coefficient, but can not to sacrifice performance for cost.

The existence of heat-conducting cream 4 avoids the existence of air, makes it possible to conductor C simultaneously and retains flexibility and less radius of curvature.The radius of curvature of the conductor C so obtained can be less than five times of conductor C diameter.

Be shown in Fig. 1 in the execution mode of 3, conductor C is wound around by arranging sheath 5.In the mode substituted, can conductor C be decorated with lace simply or be contained in more complicated conductor assembly.

Use present ring grain, curl up, the pipe of striped or corrugated contours, the execution mode substituted can be carried out.

Conductor can be arranged around pipe in many ways, such as single or many spirals, or one or more layer of one-tenth arranged in a crossed manner or finally woven.

Annular tube refers to that its outward appearance looks like the pipe of end to end ring.Spine and the recess of ring have loop of one's own respectively, as shown in Figures 5 and 6.As usual rule, if sidewall thickness is relative to the pitch or highly less of ring, so spine is to the outside outstanding and recess of pipe to pipe inside outstanding (Fig. 8 and Fig. 9).Externally, recess presents internally outstanding spine.

In modification, as shown in FIG. 11 and 12, the inside in outside with the pipe of spine in the form of a ring and recess also can be level and smooth.This shows that sidewall thickness is not definite value.

Level and smooth and the inner pipe for ripple of lateral wall also can meet this function (Figure 15).

The profile of spine and recess can cover intermediate shapes (Fig. 9, Figure 17 and Figure 18) all between sine curve and battlement (cr é neau).

Helix tube refers to the pipe alternately having and describe spine and the recess rotated around tubular axis line, has the enough compact pitch being less than the diameter of pipe, as shown in fig. 4 and 13.Pipe only has both single spine and single helical groove.

The section profile of spine and thread groove can adopt all shapes described for annular tube, especially as shown in Figure 10, Figure 11, Fig. 7, Figure 14 and Figure 16.

Just as annular tube, helix tube can be in inside level and smooth and only has spine and recess in outside, and vice versa (Figure 14 and Figure 15).

Curl up pipe and refer to that spine is wound around around pipe along the longitudinal axis.Its feature presented is identical with above-mentioned helix tube.

Bellows is sometimes used and is represented to manage similar mode on the axis of pipe, have pipe around line or spiral to curling up.

Conductor according to the present invention has multiple advantage.

More specifically, the induction loss in refrigerating circuit is very little.The useful section of copper cash is optimized to consider kelvin effect.

Novelty of the present invention is, it also makes it possible to discharge the heat resulted from isolation and insulation water loop.The discharge being convenient to loss makes it possible to use according to conductor of the present invention at higher electric current place compared with conventional conductor, or uses according to conductor of the present invention at constant current place, and does not heat component adjacent thereto.

Curling up of pipe makes it possible to maximize the heat exchange surface with cryogenic fluid, permits obtaining excellent flexibility and the body of very shallow curvature simultaneously, and does not lose refrigeration.

Result causes the high current density in high-frequency.

It is electrical isolation between cryogenic fluid and conductor.Therefore in cryogenic fluid, loop current or leakage current is not had.

These advantages make it possible to use in multiple fields according to conductor of the present invention, and more specifically, make it possible to realize high frequency and dissipate less or high current density connection line or magnetic element (inductor, transformer, induction heating inductor).

Claims (8)

1. one kind comprises the electric conductor (C) of many strands (2), described many strands (2) extend between two terminals, each every root in strand (2) has electric insulation layer (6) in its surface, strand (2) is electrically connected in parallel to each terminal of electric conductor (C), it is characterized in that, described strand (2) is set at least one pipe (1) around the formation core implemented with electrical insulating material, described pipe (1) cooled fluid flows through, and the outer surface of strand (2) and described pipe (1) is had the coefficient of heat conduction and the lotion of electric insulation (4) dipping that are greater than 0.2W/mK, to ensure the good transfer of heat between strand (2) and pipe (1).

2. electric conductor according to claim 1 (D), is characterized in that, between two ends of conductor (C), each strand (2) realizes complete winding at least one times around pipe (1).

3. electric conductor according to claim 1 and 2 (D), is characterized in that, the coefficient of heat conduction of the lotion (4) of described electric insulation is greater than 0.5W/mK.

4. the electric conductor (D) according to any one of foregoing Claims, is characterized in that, according to ISO868 standard, the shore hardness A of described lotion (4) is less than 75.

5. the electric conductor (D) according to any one of foregoing Claims, is characterized in that, described electric conductor (D) comprises oversheath (5).

6. the electric conductor (D) according to any one of foregoing Claims, is characterized in that, described pipe (1) has the geometry of ring grain shape.

7. the electric conductor (D) according to any one of claim 1 to 5, is characterized in that, described pipe (1) has spiral geometry.

8., according to the purposes of electric conductor in any one of the preceding claims wherein, be used in the frequency between 1kHz and 500kHz.