DE2116603A1 - Manufacture of waterproof electrical windings - Google Patents

Description

Manufacture of electrical windings in waterproof design The invention relates to a method for producing waterproof bus guides from electrical windings, in particular the winding head or leg parts and the Switching end exits in electrical machines where those with largely unimpregnated Windings provided with insulating material with the exception of the winding head or leg parts as well as the switch end outlets inserted in the grooves of the sheet metal core of the machines and only then the waterproof impregnation of the insulating material, e.g. by soaking with a casting resin.

Special care is required in the manufacture of waterproof windings on the winding head or leg parts and the switch end exits, because Because of the complex shape, cavities can be created at these points during application The electrical insulation materials on the electrical conductors can hardly be avoided. Is after the impregnation and hardening of the insulating material does not affect the switch end exit Eapil-l-a-renj is dense or in isolation so it can be harmful Water penetrate into the cavities and reach the electrical conductors. Whereas with windings built into the machine only after the finished impregnation If the non-waterproof products can be easily eliminated, it is with the impregnation of already installed windings necessary for economic reasons, one of In any case, ensure a waterproof design from the outset. The term "waterproof" is to be understood in such a way as e.g. by the underwater test according to the NEMA standards, NEMA M 61, Section III, Part 20.48 is defined.

In the manufacture of windings, only after impregnation are built into the machine, the water resistance is achieved in that each winding is impregnated several times. In the case of windings, however, the impregnation are already in the machine, after impregnation and hardening there is a further sealing process (e.g. pouring with GieL resins or similar) as a matter of principle also possible, but very cumbersome and, above all, uneconomical. The electric Switching connections and diversions are then already established, so that make it extremely difficult to reach the areas to be sealed. In addition, has the aforementioned method has the disadvantage that it is seldom precisely predicted can, after how many times of impregnation and hardening, actually be complete Sealing is in place. Time-consuming intermediate tests under water are necessary. The production process is therefore cumbersome and also requires a flawless one Intermediate drying before a further impregnation. In addition, mostly only the accesses to the cavities are closed, the poor thermal properties however, the cavities themselves remain.

The object of the present invention is to provide a method of the initially Specify the type mentioned, which is a simple, economical and safe waterproof Sealing of the outlets and the winding head or leg parts with only one-time impregnation guaranteed.

This object is achieved according to the invention in that before Applying the insulating material all possible cavities in the end winding or leg parts and at the switch end exits with one essentially only made of pure filler and a volatile solvent, thick but still spreadable Paste to be filled, after applying the insulating material it the solvent is removed from the paste by a drying treatment and the prepared in such a way, in the grooves inlaid windings are finally impregnated.

In an advantageous embodiment of the invention, one surrounds after filling the cavities with the paste

Leg part as well as the switch end exits with a retaining strap.

As a further advantageous embodiment of the invention, between the switching end exits before filling the cavities, the switching end and the remaining winding an angle strip of insulating material inserted '. This angle strip is previously coated with the paste on one or both sides.

Thus, by the method according to the invention with only one time Impregnation the production of a homogeneous, void-free and watertight Isolation in the winding head or

Leg part and guaranteed at the switching end exits.

Intermediate tests for water resistance are not required. The procedure is therefore rational, especially since the materials used for filling and sealing u are commercially available and cheap. The additional expenditure on filler is low compared to the effort for another otherwise usual impregnation. In addition, the Heat dissipation from the winding noticeably improved by bridging the cavities.

The method is described below with reference to the drawing using an exemplary embodiment explained in more detail: It show the J? ig. laund 1b in view and section the type of Sealing of the winding head or leg parts and Fig.2ca.2 b, 2 c in view and Cut the type of seal at the valve end outlets.

Whenever of FIG. 1 a, the Ijeiterbündel 9 are before application of tape-shaped insulating material 2 richly and generously coated with the paste 3. The paste 3 consists essentially only of pure filler * off, e.g. quartz, mica flour, Talc or similar, which for production-ready processing with a slightly volatile Solvents, e.g. methylene chloride, trichlorethylene, acetone, alcohol or similar a thick mass that is just about spreadable. The applied The amount of paste 3 must be so large that in the subsequent advantageous Umbandelung with a holding band'8, which is e.g. a glass silk band, all underneath this Retaining band 8 located cavities are completely filled (see Fig. 1 b).

Technically, this is best done in such a way that the excess Paste 3 located in advance in the respective turn to be 'wrapped, is pushed out. The strip-shaped insulating material 2, which has not yet been impregnated, is then applied the winding head or leg parts of the winding applied. After installing the so prepared winding in the laminated core of an electrical machine and the Driving out the solvent of the paste 3, which also happened before the installation The impregnation can be done e.g. by soaking in a synthetic resin bath. After the impregnation resin has hardened, there is a waterproof winding head or leg part insulation.

The method according to the invention is illustrated in FIGS. 2 a to 2 c for a switch end exit: The sealing of a switch end exit begins by wrapping the switching end 10 with a not yet impregnated Insulating tape 1 according to the necessary number of layers, with the switching end 10 slightly is raised. This is followed by the waterproof insulation of the subsequent winding head or leg parts in the area L1 in the manner as described above in the description to for installing the winding in the machine for Figures 1 a and 1 b - is indicated, but in this example here -without Using the tether. For wrapping around area L1, however, only about half of it is initially required the required layers made with the strip-shaped insulating material 2. After that, will the area L3 below the end of the switch is filled in abundantly in excess with paste 3, beforehand, for safety's sake and as an additional barrier, the angular stripes 4, which is also thickly coated with the paste 3, in the angle between Switching end 10 and the remaining winding has been inserted.

The isolated switching end 10 is now firmly on the winding head or. Leg portion of the winding pressed, removing the excess paste 3 from the area L3 is squeezed out and used to seal the sides by spreading. In the area L2, the winding is then made with about half of the required number of layers surrounded by the strip-shaped insulating material 5.

This corresponds to the one on the other side of SchaJendes 10 (im Area L1) insulating material used in the winding head or leg part 2. Bring the insulating material 5 in such a way that the area L1 is overlapped by the area L3. Afterward then the entire area L with the remaining half of the required layers with wrapped around the strip-shaped insulating material 6.

To securely set the switching end 10 and the waterproof seal to ensure, are still around the winding after applying the insulating material 6 and the switching end 10 a few turns of a heat-shrinking tape 7 wrapped. Then takes place after the solvent of the paste 3 through a drying process removed the impregnation and hardening. The band 7 shrinks at the for The temperature required for curing presses the sealing media at the switch end outlet firmly together and pulls the switching end 10 firmly to the end winding or leg part the winding.

The drying process used to remove the solvent from the paste 3 takes place mostly and without additional effort or loss of time in the course of the anyway necessary for impregnation Drying process of the remaining Winding.

The method according to the invention can in principle also be used for sealing the parts of the winding located in the area of the laminated core are only used is generally there with careful wrapping of the completely straight (and therefore also void-free) sections achieved a waterproof seal anyway.

6 pages description 4 claims 2 sheets of drawings with figures 1a, b and 2a to c

Claims (4)

P a t e n t a n s p r ü c h e U Process for making waterproof Designs of electrical windings, in particular the winding head or Leg parts as well as the switch end exits in electrical machines, in which the windings are provided with largely unimpregnated insulating material with the exception of the winding head or. Leg parts as well as the switch end exits in Grooves of the laminated core of the machines are inserted and only then the waterproof The insulating material is impregnated, e.g. by soaking it with a casting resin, characterized in that before applying the insulating material (2,5,6) all possible Cavities in the winding head or leg parts and at the switch end exits (10) with an essentially pure filler and a volatile one Solvent existing thick, but still spreadable paste (3) filled out be, after applying the insulating material it (2,5,6) the solvent from the Paste (3) is removed by a drying treatment and the prepared in this way, Windings inserted into the grooves are finally impregnated. 2. The method according to claim 1, characterized in that according to the Filling the cavities with the paste (3), the winding head or. Leg parts and the switching end outlets (10) are surrounded with a retaining band (8). 3. The method according to claims 1 and 2, characterized in that that at the switch end exits (10) before filling the cavities with the paste (3) an angle in the angle between the switching end (10) and the rest of the winding strip (4) made of insulating material is inserted. 4. The method according to claim 3, characterized in that the angle strip (4) is previously coated with the paste (3) on one or both sides. Blank page