Descriptor air-cooled steam turbine generator rotor, insulation manufacturing process 刖5 In the generators of several thousand to one million kilowatts, the working voltage of the rotor winding is 300,500, but in special cases, the rotor winding insulation sometimes bears Overvoltage of nearly 2000 or higher. At the same time, the centrifugal force generated by the high-speed rotation of the rotor will also cause the rotor slot insulation to withstand large mechanical stresses. In addition, the current density of the rotor is large, the heating temperature in the tank is high, and the thermal expansion coefficient between the rotor winding body and the insulating material is different, so that the thermal stress and the shearing force of the rotor winding insulation are also large. Therefore, it is required that the rotor insulation must have a high compressive strength. Since the introduction of the air-cooled steam turbine generator manufacturing technology of the Swiss company 88 in 1990, the company has evaluated that the rotor slot insulation of the series introduced products is directly imported, and the price is very expensive. In order to improve the introduction of technology to digest and absorb, effectively reduce the cost of the motor, improve the technical and economic indicators of the motor and market competitiveness. On the basis of repeated evaluation and a large number of experiments, the final development was successful. Now, the domestic development of the rotor slot insulation of a series of air-cooled steam turbine generators is briefly introduced.
For the evaluation of 88 companies, the structural characteristics of the series of air-cooled steam turbine generator rotors and the performance requirements of the slot insulation, we have adopted the following raw materials and manufacturing processes.
1 The main raw material edge paper poly(m-benzoyl)-aniline fiber is used as the material for pressing groove insulation. It is a kind of calendered insulating paper with high electrical strength flexibility and resilience. It has been widely used in foreign electrical equipment industry, and is mainly used in the motor for inter-turn insulation and slot insulation of the rotor. The performance parameters are as follows: elongation is 20 3 in the longitudinal direction, and shrinkage is 0.3 in the longitudinal direction. The domestic 003 epoxy glass cloth board is used as the mat.
Has been 269 as a binder.
For example, the bonded 37 steel has a shear strength of 90 days after being placed in water, and 7 is selected at room temperature, and the grade insulating cover paint is used as a moisture-proof cover paint.
2 Manufacturing Process 2.1. Pressing of slotted insulation 1 stamping design Regardless of whether the rotor groove type is trapezoidal groove or straight groove, we have designed the die to make the grooved grooved cap molding die, but at the same time, we must pay attention to learn to hold the grooved lining. The angle of the bar is convenient for weaving.
Before the pressing process is pressed, the N0mex paper must be preheated. Otherwise, when the temperature suddenly rises, the residual water in the paper will cause the surface to bulge. The preheated paper is then loaded into a mold and hot formed on a hydraulic press. And based on the mild plasticization of the paper, there are smooth corners and no creases to determine the temperature and time of press molding. We use 200, 3.01 and finally the grooved grooved caps that have been pressed, must be controlled to cool down. To make the shape stable.
For the crease caused by the extrusion, it can be solved by attaching a thin 1 paper.
2.2 Processing of the bottom pad of the groove In order to improve the bonding strength between the pad and the N0mex paper, the two sides of the pad must be ground, because our company has no special reason, which improves the flatness. Then, after grinding with a freshly cleaned sanding roller to the size requirement, it is then ground with a sanding roller that is covered with debris, which not only ensures the accuracy requirement, but also causes the grinding machine to grind the two ends.
2.3 Bonding In order to improve the adhesion, the bottom of the grooved grooved cap is slightly roughened and marked according to the size of the gasket so that the gasket can be just placed in the middle of the bottom of the grooved liner cap when bonding. At the same time, the plastic is rolled into a funnel, and the inside is filled with a good adhesive 269, and then a small opening is cut at the tip of the funnel, and the adhesive is extruded to uniformly coat the middle portion of the mat. This will prevent the mat and the strip. The adhesive is extruded on both sides of the type of insulation to affect the welt. Finally, the pad is glued to the bottom of the slot liner cap. The inner mold and the protective material are placed in a hydraulic press to form. In addition, in order to eliminate the influence on the curing process due to the difference in the shrinkage rate of the adhesive pad paper, we used a method of cooling the inner mold to room temperature.
2.4 Electrical test The solar lining insulation of the bonded mat is tested for electrical performance. Since the slot lining size is longer 2.6, 1 or so, the material is relatively soft. After analysis, we have completed the test by using the internal and external compression molds as electrodes. Its pressure test is 9.5, 5060, and 1 claw without breakdown.
2.5 Drying process at 15, 潞姹5 to remove residual moisture, the purpose of this is to make the size after trimming the actual size of the grooved grooved cap. Then use a special device to trim the edges so that the cut edges are free of burrs. The single-arm drilling machine is used to drill the groove liner. Due to the flexibility and flexibility of the material, it is difficult to locate when drilling. Therefore, we designed a special fixture and simply processed the drill bit so that the drilled hole is just right. At the center of the groove substrate portion and without burrs. At the same time, the slot cap is loaded into a special mold and punched in the punch.
2.6 Moisture-proof treatment In order to prevent, 1 paper absorbs moisture, so spray moisture-proof cover paint immediately after machining. After spraying the varnish, the performance test results of the paper sample are volume resistivity. Normal immersion 66 after relative humidity 82. Electrical strength 3 Summary Turbine generator rotor slot insulation adopts paper press forming technology, and the groove shape is selected reasonably. After the corner molding temperature and pressure, the material has high electrical strength flexibility and resilience, making it easy to enter the trough, easy to attach to the trough shape, higher heat resistance, and can maintain good insulation performance under 2201 continuously. Years of age, thus ensuring the formation. Mechanical properties of the slot insulation electrical properties and electrical aging properties. At the same time, the service life of the slot insulation between the rotor copper wire and the zero paper. The slot liner cap insulation produced by this process has been widely used in the rotors of the champion series turbine generators introduced by our company. But at the same time, we also realized that because the company's equipment for slot insulation is relatively simple and the degree of automation is not high, it will cause material waste to a certain extent. In order to improve the utilization rate of materials, our company has considered drawing on the advanced experience of foreign countries and using short-mode continuous displacement hot pressing method to suppress this new type of slot insulation.
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