RU2082244C1 - High-capacity and high-voltage disk transformer - Google Patents

Abstract

FIELD: electrothermy; induction heating; electrothermic plants for high-frequency welding of metals, soldering, meeting, hardening, and other operations. SUBSTANCE: transformer has coaxially arranged disk-type multiturn spiral primary winding made of ribbon with input and output unions on ends and single-turn secondary winding. Insulator with internal channel is fitted between windings. Primary winding is placed in insulator channel in symmetry plane equally spaced from disks. EFFECT: enlarged functional capabilities, improved design. 2 dwg

Description

 The invention relates to electrothermics, in particular to induction heating, and can be used in electrothermal installations for high-frequency metal welding, melting, brazing, hardening and other operations.

 A powerful transformer with disk primary and secondary windings separated by a dielectric is known (L. Tyr "Transformers for installations of induction heating of high frequency", M.-L. state energy. Ed. 1961, p. 134). A disadvantage of the known transformer is the increased consumption of copper.

 Closest to the proposed technical solution and adopted for the prototype is a transformer containing a multi-turn disk primary winding (see ibid., Fig. 5 4, p. 135), made of a copper profiled tube coated with insulation, and a single-turn secondary disk winding.

 A disadvantage of the known device is the increased consumption of copper and the high complexity of manufacturing the primary disk winding.

 The technical problem solved by the invention is to reduce copper consumption and improve the manufacturability of the design of a high-frequency transformer.

 The problem is solved due to the fact that in a high-power disk high-frequency transformer containing coaxially located disk primary multi-turn spiral winding with input and output fittings at the ends and a secondary single-turn winding with a dielectric placed between them, according to the invention, the dielectric is made with an internal channel, the primary winding made of tape and placed in the dielectric channel in a plane of symmetry equidistant from the secondary winding disks.

In powerful high-frequency transformers, due to the surface effect, current flows through a thin surface layer of the winding, for example, at a frequency of 440 kHz. The current penetration depth in copper is 0.11 mm, the current density in the winding reaches 100 A / mm ² , the specific losses attributed to the entire structural weight of the windings reach 2000 W / kg.

 Such high specific losses inevitably require particularly intensive cooling methods, and therefore the windings of high and high frequency transformers are made of profiled copper (rectangular cross-section) tubes through which water is passed with a guaranteed flow rate. That is how the windings of the analogue (book of L. Tire, p. 134) and the prototype (see ibid., Fig. 5 4, p. 135) are made.

 Profiling and winding of a copper tube is carried out on special equipment (see ibid., P. 217 220), which leads to an increase in production (technological) costs, especially in a single production. At the same time, the working surfaces of the primary winding made of a rectangular copper tube have significant non-flatness due to the deflection of the walls and rounding corners, which requires an increase in the width of the working surface of the profile, the gaps between the turns and the gaps between the working surfaces of the primary and secondary windings and, as consequence, increase in overall dimensions and weight. In addition, the efficiency is reduced due to the worse coupling of electromagnetic fluxes between the primary and secondary windings.

 The proposed design is free from these drawbacks, allows you to make a transformer with high accuracy and with less labor and consumption of non-ferrous metal, as well as increase efficiency.

 According to the invention, the multi-turn primary winding of a high-frequency transformer is made of a sheet of copper, during mass production it is stamped, with a unit manually by scissors, or by milling in a bag on general industrial equipment.

 The primary winding of the tape in the form of a flat spiral can significantly reduce copper consumption and reduce production costs.

 To ensure intensive cooling of the primary winding, the dielectric is made with an internal channel, in which the winding is placed in the axial plane of symmetry so that running water supplied to the channel through the inlet nipples batches the winding tape from both sides, and the distance from the plane of the spiral winding to the plane of the disks the secondary winding is set equal and minimally permissible for breakdown.

 In electrical parameters, the primary winding made of a profiled copper tube and a copper tape is the same, because due to the effects of "proximity" and "surface", the high-frequency current flows only along the surfaces of the windings facing each other. The surfaces of the "edges" of the windings from both the tube and the tape are not involved in the conductivity, while the copper consumption for the manufacture of the winding from the tape is 3-4 times less than from the tube, and in terms of the entire design of the transformer, the copper consumption is less than 1.5 2.0 times. In addition, for the manufacture of the proposed transformer there is no need to use special equipment, which leads to lower production costs. The inventive design of the transformer is compact, has smaller dimensions, which makes it easier to integrate it into the production line.

 Thus, it is these essential features of the present invention that can reduce copper consumption and improve the manufacturability of the transformer design both in manufacture and in operation.

 In FIG. The design of a disk high-frequency transformer is presented.

 In FIG. 1 is a side view; FIG. 2 is a top view. The transformer consists of a primary four-turn winding 1 made of copper tape, which is placed in the axial plane of symmetry of the water-cooled dielectric channel 2. The dielectric is made of two symmetrical parts 3 and 4, hermetically connected to each other, for example, using glue, after placing the primary winding 1 in the channel 2. At the ends of the winding 1, the inlet 5 and the outlet 6 are welded, which serve to supply and drain water, and also being electrical clamps for connecting the primary winding to a high-frequency voltage source.

 The dielectric 3, 4 with the primary winding 1 is placed coaxially between the disks of the secondary winding 7, 8. The disks of the secondary winding through the output buses 9, 10 are connected together in parallel, and a process circuit (not shown) is connected to the output buses, an inductor, a conductor etc. In FIG. not shown also fasteners and cooling of the secondary winding.

 The transformer operates as follows. When a high-frequency voltage is applied to terminals 5, 6, a current flows through the primary winding 1, which, according to the law of electromagnetic induction, excites a current in the secondary winding (when the load is connected), while the voltage on the load depends on the ratio of the turns of the primary and secondary windings, as well as on the nature load. Thus, the load is consistent with the source of high-frequency energy in terms of parameters, which is the essence of the use of a high-frequency transformer.

High-frequency current flowing through the windings heats the latter. To cool the primary winding in the nozzle 5 serves water under low pressure - up to 2 kg / cm ² . Water, flowing in the dielectric through channel 2, washes the primary winding tape 1 on both sides, intensively cools the latter and through the nozzle 6 water is drained into the cooling system. The cooling of the secondary winding 7, 8 occurs through copper tubes (not shown) soldered to the outer surface of the disks of the secondary winding.

 The proposed design of a high-frequency transformer allows, due to the high accuracy (flatness) of the primary winding, to ensure uniform distribution of current on surfaces and magnetic fluxes of adhesion at minimal cost, to exclude local current concentration and to exclude breakdown of the dielectric with a significant increase in current density.

 The high-frequency transformer was tested on the TESA 20-114 pipe-welding mill of the Chelyabinsk plant Santehdetal in the production of 45 mm diameter water pipes.

 The use of a high-frequency transformer of the claimed design allows to reduce the total copper consumption up to 20 25% to reduce production costs.

Claims (1)

 Powerful high-frequency disk transformer containing coaxial disk primary multi-turn spiral winding with inlet and outlet fittings at the ends and a secondary single-turn winding with a dielectric placed between them, characterized in that the dielectric is made with an internal channel, the primary winding is made of tape and placed in the dielectric channel in the plane of symmetry equidistant from the secondary disks.

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