MXPA98002036A - An isolated driver and procedure to make a driver isolated - Google Patents

Abstract

A method for making an insulated conductor in accordance with the present invention includes extruding an insulating material in a conductor and then winding the insulating material in the conductor to a prescribed thickness, the extrusion step comprising extruding the insulating material to a thickness of about 0.00635 cmýa approximately 0.00889 cmý, and the rolling step comprises winding the insulating material to a thickness of about 0.003175 cmýa approximately 0.00801 c

Description

AN ISOLATED DRIVER AND PROCEDURE TO MAKE AN ISOLATED DRIVER FIELD OF THE INVENTION The present invention relates generally to an insulated conductor and to methods for making an insulated conductor, and more particularly to methods for making a high voltage insulated electrical conductor for use in electrical transformers. Still more particularly, the invention relates to an insulated conductor and to a method for making an electrical conductor with an insulation coating disposed therein of thickness from about 0.003175 cm2 to about 0.008001 cm2.

BACKGROUND OF THE INVENTION Rectangular conductors with high dielectric strength insulation, such as polyphenylsulfone, are coated by the use of thermoplastic extruders equipped with heads designed to coat rectangular conductors. Typically, the extruded insulation coating thickness scale is about 0.00635 cm2 (the minimum that can be obtained) to about 0.00889 cm2 (it can be easily obtained). One of the disadvantages of the extrusion head is that the thickness of the coating can not be controlled to thin coatings of less than 0.00635 cm2 being controlled to thin coatings of less than 0.00635 cm2. Accordingly, an object of the present invention is to provide a method for making electrical conductors wherein the thickness of the extruded coating can be reduced by about 10% to about 50% to provide a scale of reduced insulation thickness of about 0.003175 cm2 to approximately 0.008001 cm2 depending on the extruded starting thickness and the percent reduction used. The method according to the invention provides a coating of insulating material which may have a prescribed thickness less than that produced by the extrusion process (s) available at present.

BRIEF DESCRIPTION OF THE INVENTION An insulated conductor comprising an electrical conductor and an insulating coating disposed in the conductor is provided. According to the invention, the coating has a thickness of about 0.003175 cm2 to about 0.004445 cm2. A method for making an insulated conductor in accordance with the present invention includes extruding an insulating material in a conductor and subsequently winding it down by reducing the coated conductor, so that the insulating material in the conductor is crimped by about 10% to about 50% at a prescribed thickness and the driver assumes a prescribed thickness and width. The extrusion step preferably comprises extruding the insulating material to a thickness of about 0.00635 cm2 to about 0.00889 cm2 and more preferable to a thickness of at least about 0.00635 cm2, and the winding step preferably comprises winding the insulating material to a thickness of about 0.003175 cm2 to 0.008001 cm2 and preferably at a thickness of about 0.003175 cm2 to 0.004445 cm2. In a preferred embodiment of the invention, the insulating material is a thermoplastic polymer, such as polyphenylsulfone. In addition, in preferred embodiments of the invention, the conductor is generally rectangular in cross section. The preferred embodiment of the invention also includes winding the conductor to a reduced thickness and increased surface area, i.e., the winding step includes winding the insulating material to a prescribed thickness and at the same time winding the conductor to a reduced thickness. In this way, both the thickness of the coating and the shape of the coated product are altered in the winding step. Other features of the invention are described below, BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 schematically illustrates an extruder and the method for extruding an insulating material on the surface of a rectangular conductor. The product of the extrusion process is a conductor 10 comprising an electrical conductor 12 and an insulating coating 14, Figure 2 schematically illustrates the winding step in accordance with the present invention, wherein up to four rolls 16a-16d are employed for winding the insulating coating to a desired thickness, and at the same time altering the shape (thickness of surface area) of the electrical conductor 12. Figure 3 illustrates a form of transformer; a transformer 20 comprising a pair of coils 1 0 '(that is, coils composed of an insulated conductor according to the present invention) and a core 18.

DETAILED DESCRIPTION OF THE PREFERRED MODALITIES The present invention employs developed conductor sizes which can be reduced to the desired dimensions with the desired thickness of insulation. The presently preferred embodiments of the invention employ reducing rolls. This invention, when applied together with the thermoplastic extruder, allows rectangular conductors (eg, aluminum or copper) to be produced with the desired conductor dimensions and insulation thickness. This invention can be used to control the insulation thickness of either of the two opposite sides of the conductor, or of all four sides, depending on the configuration of the roller.

As mentioned, the extrusion of thermoplastic coatings in rectangular conductors is generally limited to a minimum thickness of 0.00635 cm2. This is an inherent limitation due to the manner in which the extruder heads presently available, and their associated die components, apply the molten polymer to the conductor. This extrusion process is represented by the block bearing the same name in Figure 1. A product of this process is a conductor 10 comprising the electrical conductor 12 and its associated insulating coating 14, wherein the coating has a minimum thickness of 0.00635 cm2 As indicated above, the thickness of the extruded insulation coating can vary from about 0.00635 cm2 (the minimum that can be obtained) to about 000889 cm2 (it can be easily obtained). The polymers applicable to high voltage conductors used in transformers 20 (Figure 3) must have performance characteristics that ensure functional life performance for up to 25 years. These polymers have dielectric stresses that allow them to be used with coating thicknesses of less than 000635 cm2, that is, on a scale of about 0003175 cm2 to about 0008001 cm2 and preferably on a scale of about 0003175 cm2 to about 0004445 cm2 The product of the process of the invention described herein is a rectangular conductor 10 '(see Figure 2) having an insulation of a thickness that meets the dielectric needs of the transformer, but does not exceed said need by an excessive amount. Excessive insulation is costly not only from a material cost point of view but also from a space factor point of view, which is a damage to maintaining a small core / coil assembly 18, 10 '(see figure 3) . The size of the core / coil assembly is equivalent to the cost of the transformer 20, not only in materials used but also in the prevention of electrical losses. In accordance with the present invention, a series of reducing rollers is used to reduce the insulation thickness. The reduction rollers can be configured in different ways, such as two flat rollers with parallel axes or a flat roller in combination with a grooved, slightly tapered roller, or four flat rollers (one on each side of the conductor 12) or four flat rollers as configured as to what is common as a head of "Turks". These different configurations are generally represented in Figure 2, which illustrates four flat rollers 16a-16d. The final size of the conductive product (i.e., the conductor and insulating coating) with its desired insulation thickness is produced by the development of a conductor starting size with a thickness that can be extruded from insulation that when rolled up it produces a conductor of the desired or predetermined dimensions with the desired or predetermined thickness of insulation.

For the application of the particular transformer for which the isolated conductor / process was developed according to the invention, the conductor typically has a width of no more than about ten times its thickness and the insulation thickness is around 0.003175 cm2 to 0.004445 cm2 . Nevertheless, depending on the performance characteristics required, operating life functional periods, polymer used, dielectric stresses, etc. , even smaller coating thicknesses are possible according to the method of the present invention. For example, the coating thickness of less than 0.003175 cm2 can be used for certain applications, as will be understood by those skilled in the art, and such reduced coating thicknesses can be obtained by the method of the invention described herein. The procedure involves the extrusion of a conductor in cross section larger than the desired final size. This conductor is then coated by extrusion with thermoplastic insulation. The thickness of the coating, for example, can be approximately 0.00635 cm2, which is the minimum possible thickness for the extruders currently available. The coated conductor is then wound into a desired, final thickness and width in cross section. During the winding step, the ratio of the conductor surface to the volume of the conductor increases as the cross section of the conductor changes from a rectangular shape to a rectangular rectangular shape, i.e. as the thickness of the conductor. This means that the insulation thickness is reduced below the original 0.00635 cm2, resulting in a more efficient conductor. The typical dimensions, in square centimeters, of a reduced conductor in a two-way roller are: - base conductor starting size = 0.28956 cm2 in thickness x 0.41148 cm2 in width. - Coated conductor starting size = 0.30226 cm2 thick x 0.42418 cm2 wide. - uncoated conductor size rolled = 0.18415 cm2 thick x 0.53086 cm2 wide. -rolled coated conductor size = 0.19304 cm2 thick x 0.53848 cm2 wide. In brief, the present invention employs one or more roller means or apparatus for altering the shape of the coated conductor to achieve a desired or predetermined insulation thickness. The above description of the preferred embodiments should not limit the scope of protection of the following claims. Thus, for example, except where they are expressly limited, the following claims are not limited to the procedures employing any particular number, configuration, or roller shape or means or apparatus.

Claims (39)

1. - An isolated conductor method comprising: (a) extruding an insulating material in a conductor; and (b) winding said insulating material in said conductor to a predetermined thickness.

2 - A method according to claim 1, wherein step (a) comprises extruding said insulating material to a thickness of about 0.00635 cm2 to about 0.00889 cm2.

3. A method according to claim 2, wherein step () comprises winding said insulating material to a thickness of about 0.003175 cm2 to about 0.008001 cm2.

4, - A method according to claim 1, wherein step (a) comprises extruding said insulating material to a thickness of at least 0.00635 cm2.

5 - A method according to claim 4, wherein step (b) comprises winding said insulating material to a thickness of less than 0.00635 cm2.

6 - A method according to claim 4, wherein step (b) comprises winding said insulating material to a thickness of about 0.003175 cm2 to about 0.004445 cm2.

7. A method according to claim 1, wherein said insulating material is a thermoplastic polymer.

8. - A method according to claim 7, wherein the thermoplastic polymer comprises polyphenylsulfone.

9. A method according to claim 1, wherein said conductor is rectangular in general.

10. A method according to claim 1, wherein step (b) comprises winding said conductor to a reduced thickness.

11. A method according to claim 1, wherein step (b) comprises winding said conductor to an increased surface area.

12, - A method according to claim 1, wherein step (b) comprises employing at least two flat rolls.

13 - A method according to claim 1, wherein step (b) comprises employing at least one tapered, slotted roller.

14, - A method according to claim 1, wherein step (a) comprises extruding said insulating material to a thickness of at least 0.00635 cm 2; said conductor is rectangular in general; and step (b) comprises winding said insulating material to a thickness of about 0.003175 cm2 to about 0.004445 cm2, and winding said conductor to a reduced thickness and increased surface area.

15. An insulating conductor comprising: a) an electrical conductor; and b) an insulating coating disposed on said electrical conductor, said insulating coating having a thickness of about 0.003175 cm2 to about 0.008001 cm2.

16. An insulating conductor according to claim 15, wherein said electrical conductor is aluminum.

17. An insulating conductor according to claim 15, wherein said conductor is copper.

18. An insulating conductor according to claim 15, wherein said insulating material is a thermoplastic polymer.

19. An insulated conductor comprising: a) an electrical conductor; and b) an extruded insulating coating disposed on said electrical conductor, said extruded insulating coating having a thickness of about 0.003175 cm2 to about 0.004445 cm2.

20. An insulated conductor according to claim 19, wherein said electrical conductor is aluminum.

21. An insulated conductor according to claim 19, wherein said electrical conductor is copper.

22. An isolated conductor in accordance with the claim 19, wherein said insulating material is a thermoplastic polymer.

23. A transformer coil comprising an insulated conductor comprising: a) an electrical conductor; and b) an insulating coating disposed on said electrical conductor, said insulating coating having a thickness of 0.004445 cm 2 or less.

24.- A transformer coil according to claim 23, wherein said electrical conductor is aluminum.

25. A transformer coil according to claim 23, wherein said electrical conductor is copper.

26, - A transformer coil according to claim 23, wherein said insulating material is a thermoplastic polymer.

27. - A transformer comprising a core and a coil, said coil comprises an insulated conductor comprising; a) an electrical conductor; and b) an insulating coating disposed in said electrical conduit r, said insulating coating having a thickness of 0.004445 cm2 or less.

28. A transformer according to claim 27, wherein said electrical conductor is aluminum.

29. A transformer according to claim 27, wherein said electrical conductor is copper.

30. A transformer according to claim 27, wherein the insulating material is a thermoplastic polymer.

31 - A method for making an insulated conductor comprising: a) extruding a thermoplastic polymer in a conductor to form a conductor having an insulated coating thereon; b) winding said insulated and conductive coating to produce a conductor of predetermined width and thickness and a coating of predetermined thickness.

32. A method according to claim 31, wherein step (a) comprises extruding said polymer to a thickness of about 0.00635 cm2.

33.- A method according to claim 32, wherein step (b) comprises winding said thermoplastic polymer to a thickness of about 0.003175 cm2 to about 0.004445 cm2 and said conductor to a width of not more than ten times its thickness .

34 - A transformer coil comprises an insulated conductor comprising: a) an electrical conductor; and b) an insulating layer of extruded thermoplastic polymer disposed on said electrical conductor; said coating has a thickness of about 0.003175 cm2 to about 0.004445 cm2 and said electrical conductor has a width of not more than ten times its thickness.

35.- A transformer comprises a core and a coil, said coil comprises an insulated conductor comprising: a) an electrical conductor; and b) an insulating coating of extruded thermoplastic polymer disposed on said electrical conductor; said coating has a thickness of about 0.003175 cm2 to about

0. 004445 cm2 and said electric conductor has a width of no more than ten times its thickness.

36. - A transformer comprises a core and a coil, said coil comprises an insulated conductor comprising: a) an electrical conductor; and b) an insulating layer of extruded thermoplastic polymer disposed on said electrical conductor; said coating has a thickness of about 0.0031 75 cm2 to about 0.008001 cm2 and said electrical conductor has a width of no more than ten times its thickness.

37. - A method for making an insulated conductor comprising; a) extruding an insulating material in a conductor to a predetermined thickness; and b) winding said insulating material to reduce the thickness thereof by about 10% to about 50% to provide a thickness of the insulating material reduced from about 0.003175 cm2 to about 0.008001 cm2.

38 - A procedure in accordance with the indication reiv 37, wherein step (b) includes winding said conductor to produce a conductor of predetermined width and thickness.

39. - A method according to claim 38, wherein step (b) comprises winding said insulating material to a thickness of about 0.003175 cm2 to about 0.004445 cm2 and said conductor to a width of not more than ten times its thickness. SUMMARY A method for making an insulated conductor in accordance with the present invention includes extruding an insulating material in a conductor and then winding the insulating material in the conductor to a prescribed thickness; The extrusion step comprises extruding the insulating material to a thickness of about 0.00635 cm2 to about 0.00889 cm2, and the winding step comprises winding the insulating material to a thickness of about 0.003175 cm2 to about 0.008001 cm2.