CS224027B1 - Varnished wires with thermostisking layer for windings of electric machines and equipment and method of its manufacture - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to lacquered wires with a thermo-adhesive layer for the winding of electrical machines, and to devices where the threads and the winding layers are reinforced by gluing. The purpose of the invention is to provide technically, technologically and economically more advantageous types of lacquered wires suitable for use in systems with a higher temperature load.

Varnished wires with a thermo-adhesive layer make it possible to create windings and coils for electrical machines and devices with higher mechanical strength and operational reliability. This is achieved by bonding the threads and layers of the insulated wire after winding and during curing of the thermosetting adhesive layer to form a compact layer.

The basic electroinsulating lacquer layer applied to the conductive core and cured by a conventional manufacturing process ensures the basic physical, electrical and thermal properties of the lacquered wires. The thermo-adhesive functional layer applied to the base electrical insulation layer must not impair the electrical insulation, physical, mechanical and other essential characteristics of the coated conductors, either before or after winding and activation of the functional layer. The choice and application of suitable materials is therefore very limited.

The adhesive layer applied to the base electrolysis layer must remain stable and inert under normal and / or normal temperatures. at high temperature determined by working conditions. In the case of long-term shelf life, the workability of the lacquered wire, ie it must have good resistance to cracking and abrasion even at high winding speeds. After winding the coil, the thermosetting layer is activated by heat until a continuous connection of the straight threads and the electrical properties are achieved. For activating the adhesive layer of the used lacquer wire. Molding jigs can also be used for better connection.

In the prior art products of this type, the thermo-adhesive coating negatively affects the quality of the lacquered wires, their resulting mechanical, physical and electrical properties. Upon activation of the adhesive layer with a low reflow temperature, they lose their flexibility and adhesion when they are subjected to high impact temperatures, and the use of such wires is disadvantageous, respectively. technically and economically expensive designs. Negative changes in the basic technical and application parameters compared to similar lacquered wires without a thermo-adhesive functional layer result in low abrasion resistance, making it impossible to utilize high winding speeds of machine winding. The production of lacquered wires is currently discontinuous due to different temperature and cure speed of the basic insulating and thermo-adhesive layers. continuous, by adding another furnace.

Disadvantages of the prior art are eliminated according to the invention by such a solution of a lacquered wire with a thermo-adhesive layer, wherein on an electroconductive core with a base cured electro-insulating layer of solvent or solvent-free thermosetting resin varnish. of a non-solvent-free solvent-free lacquer. On this layer there is then another cured protective layer with a thickness of 0.003 to 0.007 mm of the same varnish or varnish of the type of which the base electrical insulating layer is on the electroconductive core.

After formation and curing of the base thermosetting lacquer layer, preferably a polyesterimide or polyamideimide lacquer on the conductive core, the coating is applied continuously with a calibrated wiper heated to the melting point of the lacquer, a lacquer layer of 0.005-0.01 mm of curable, solvent-free polyesterimide lacquer . This coating is left to set only at ambient temperature, it may be a coating of one or two layers of curable solvent-free polyesterimide or polyamideimide varnish. A further protective layer of a thickness of 0.003 to 0.007 mm is then applied to this uncured layer by a continuous process of the same varnish or of the type of which the base electrically insulating layer is. The protective layer is continuously cured under the same technological conditions as the base insulating layers.

The base electro-insulating layer of the lacquered wire according to the invention is made of several cured layers of a heat-resistant solvent or solvent-free thermosetting resin varnish, wherein the solvent-free type of coating is generally considered to have a dry matter content above 80%.

The thermo-adhesive functional layer forms a single or double coating on the base insulating layer, using a solvent-free lacquer, respectively. bitumen] of the same type as the base layer. This layer, not cured, only solidified at normal temperature.

The protective layer ensuring abrasion resistance of the lacquered wire at high winding speeds and long-term shelf life while retaining other critical properties is formed by one or two deposits of a defined type of thermosetting resin varnish.

Conventional types of solvent and solvent-free electroinsulating varnishes for higher temperature flashes, for example based on polyesterimides or polyamidimides, are suitable for forming the base insulating layer. The thickness of the cured insulating layers depends on the application and complies with IEC requirements for insulation quality.

The thermo-adhesive functional layer comprises a coating of one or two layers of a solvent-free bituminous varnish consisting, for example, of 85% dry weight polyesterimide and 15% cresol solvent with the addition of 0.1 to 4% triethanolaminititanate on the bitumen varnish as a curing agent. The resin solids consisted of 65% polyester] and 35% imide component. Thickness. The thermally adhesive functional layer is in the range of 0.005 to 0.01 mm depending on the area of use.

This layer is only allowed to solidify, it hardens after winding of the lacquered wire. Solvent or solvent-free lacquers of the same chemical composition as the base insulating layer may be used to protect this uncured thermo-adhesive layer. In the case of the solvent type, the bituminous varnish has a composition of: 35% polyesterlmide component (dry matter) and 65% cresol solvent with the addition of 2% butyl titanate per esterlmid as curing catalyst.

The protective layer has one or two coats cured continuously with a total thickness of 0.003 to 0.007 mm.

Upon winding of the lacquered wire and after the normal heat activation of the uncured thermo-adhesive layer, the thin protective layer is broken and the soaked thermo-adhesive coating fills the coil spaces, adjacent threads and layers are mechanically stabilized after curing. Example 1

An insulated Cu wire of 0.50 mm diameter was produced on a conventional machine with a base electrical insulating layer of a polyesterimide-based solvent lacquer applied and cured in five layers, which were cured at 520 ° C and a draw speed of 16 m / min.

The cured base insulating layer was then coated with a caliper wiper heated to 120 ° C with a solvent-free lacquer composition of 83% polyesterimide + 2% triethanolaminate and 15% cresol. This layer was allowed to solidify in air and did not cure. In a continuous process, a protective film of solvent-based polyesterimide lacquer, containing 34% polyesterimide with 1% butyl titanate and 65% cresol, was applied in two layers to this layer with a maximum thickness of 0.01 m. The thickness of the protective layer was a maximum of 0.007 mm and cured under the same conditions as the base insulating layers, at a temperature of 520 ° C and a draw-off speed of 16 m / min.

Example 2

A lacquer wire manufactured on machinery as in Example 1, with three layers of a basic electroinsulating, solvent-free polyesterimide lacquer of the same composition as in Example 1. The insulating layer was cured at 520 ° C and a withdrawal speed of 20 m / min. One layer of solvent-free varnish of the same composition as the base insulation layer was applied to this cured layer. It was applied with a caliper wiper heated to 120 ° C. The thermo-adhesive layer was allowed to solidify at ambient temperature and then a single protective layer of a solvent-free polyesterimide lacquer was applied and allowed to cure at 520 ° C and a draw speed of 20 m / min. The curing agent was triethanolamine titanate in 2% addition to polyesterimide.

The curing conditions of the base and protective layers were chosen not to activate the adhesive layer.

The lacquered wire according to the invention is flexible, long-term storable with good workability while maintaining good electrical insulation properties. After winding the lacquered wire, the coils were heated with either Joul heat for 70 sec. at 270 ° C or in an oven for 15 to 30 minutes at 230 ° C. By thermal activation, the thermo-adhesive layer was activated and adjacent threads and coil layers become fused. Strengthening of the spool was also ensured by pressing tools.

Varnished wires made according to the invention were tested according to ČSN 34 7010 and other related standards; Coil strengthening coefficient was evaluated according to ČSN

3150 part 12.

Characteristic values of test specimens of Cu wire 0,50 mm in diameter:

breakthrough stress (kVJ 7.4 ductility of the base insulating layer in the delivered state (xd) 1 ductility of the thermo-adhesive layer in the delivered state (xd) 5 thermoplasticity (° C) 310 abrasion resistance (number of shifts) 27 coil reinforcement coefficient at 23 ° C 9.5 Coil Strength Coating at 155 ° C 7.67 Coil Strength Coating at 180 ^& C 4.46

Use of the solution according to the invention is possible in cable rooms, in plants producing lacquered winding wires.

Claims (2)

SUBJECT 1. Varnished wires with a thermo-adhesive layer for winding and electrical machines and apparatus, characterized in that on the electrically conductive core with a base, a cured electro-insulating layer of a solvent or solvent-free thermosetting resin varnish, preferably polyesterimide or polyamidimide type varnish, up to 0.01 mm of the cured, non-cured electroinsulating polyesterimide solvent-free lacquer, and on this layer another 0.003 to 0.007 mm thick cured protective layer of the same lacquer or of the type of which the base electrical insulating layer is on the conductive core . 2. A process for the production of lacquered wires having a thermo-adhesive coating for winding electrical machines and apparatus according to claim 1, characterized in that after the formation and curing of a base thermosetting lacquer electro-insulating layer, preferably of polyesterimide or polyamideimide lacquer on the electroconductive core, Continuously, using a calibrated wiper heated to the melting point of the lacquer, a lacquer layer of 0.005 to 0.01 mm of curable, solvent-free electroinsulating polyesterimide lacquer, this coating is allowed to solidify at ambient temperature and then continuously applied to this uncured layer with a total thickness of 0.003 to 0.007 mm. a layer of the same lacquer, or a lacquer of the same type, of which the base insulating layer is, and this coating of the protective layer is continuously cured under the same technological conditions as the base layers.