Research on air-cooled turbine generator hollow conductor rotor coil technology Zhang Zhonghai, Shandong Jinan Power Generation Plant, Difficulties and key points in the manufacturing technology of ZhongLai coil, introduction of main process and selection of process equipment.
1 Introduction The development of rotor coils for air-cooled turbo-generators is an important lesson for Shandong Jinan Power Generation Equipment Factory to complete the introduction and introduction of 88 company's air-cooled turbo-generator manufacturing technology and to realize the replacement of imported rotor coils by itself.
Xian 8 air-cooled turbine generator rotor coil consists of two half coils. Each half coil consists of several half-edge turns. Half-line crucibles use rectangular hollow copper wire directly. The middle part of the wire is provided with a circular through hole, and two well-designed tongue-shaped inlet and outlet openings are formed at both ends. After the inserting line, a type 7 duct is formed in the rotor slot. The cooling air passes through the hollow conductor directly, and the generated tropics are walked and cooled. The effect is good. Due to the unique design of this type of coil, there is no similar manufacturing process and equipment in the country. Shandong Jinan Power Generation Equipment Factory therefore studied the manufacturing process of air-cooled rotor coils. According to the company's technical requirements, combined with the specific conditions of the factory, the production process of the rotor coil was determined. In the production of rotor coils, the main process is drilling chamfering internal cleaning punching compression annealing annealing bending 90 bending forming bending connection. Based on this, the CNC vertical production center was selected and hollow wire internal cleaning equipment was developed. Punching Pressure Forming Equipment Intermediate Frequency Annealing Equipment Bend 90 Bend Equipment End Forming Equipment Milling Connections Equipment, etc., Constituted Rotor Received Date 199, Team 10 Coil production line. Combined with the study of the operating method, the process technology in the rotor coil manufacturing process is difficult to solve 2 technical difficulties and the main process equipment and application of air-cooled turbine rotor coil, using rectangular hollow copper wire. In the production process, the main technical difficulties, the main process equipment and application are as follows.
2.1 Hollow Wire Drilling and Chamfering Each half of the coil set consists of a fixed number of rectangular hollow wires, each wire has a specified number of holes, the size of the hole is the same.
Compared with the hole position requirement, the cutting theory shows that drilling a hole in a hollow thin-walled part has a greater influence on the machining accuracy. To ensure the hole size and position accuracy, to avoid the concave wire surface becomes the focus of the drilling process. After the drilling, the edges require chamfering. The two chamfers on the outside are easier to complete. The internal chamfering becomes difficult. To pour the inner edges and corners, the tool must be able to enter the hole and make cutting feeds. Obviously it is not appropriate to complete this work by the worker directly operating the machine. After investigation and selection of relevant equipments at home and abroad, drilling machine tools have purchased German JL 12181 CNC production center. The main technical parameters are as follows: max. drilling diameter mm spindle speed r.mirT1 line v, axis feed rate set X position Y Fine Max. Tapping Diameter mm Spindle Torque Nm Tool Magazine Capacity Max. Tool Weight kg Tool Change Time s Table Size mm Repeat x Set Y Bit Y Tool Drill Hole The coated drill bit is selected and the chamfering tool is used. The contents of the process, drilled twice, without coolant.
About the minutes of the first hole diameter, the chisel edge and the apex angle were sharpened, the cutting speed was about 50, and the feed amount was about 0.15 1. The entire hole was completed for the first time, and the cutting speed was about 58 feeds. The chamfer is also divided into two, each completing two on the same wall. The cutting depth is the chamfer dimension, and the rotation speed is about 30017. For example, the feed amount is about 0.008, and the cutting range is greater than 360. The machined workpiece meets the requirements. The selection of machine tools and tools has the features of automation, wide application range, wide application, and easy processing.
2.2 Removal of Conductor Internal Contaminants Rectangular hollow copper conductors inevitably cause internal dirt, such as oily copper rust, during the process of cold drawing, transportation, storage, and drilling. If they are not cleaned, the performance of the generator will be seriously affected. The dirt inside the long wire is removed and cannot be removed by chemical methods or cleaning. It is time-consuming and laborious and extremely inconvenient. After testing, the arrow brushes with felt on the tail passed under the action of compressed air, the effect is good, and it is simple and convenient. The arrow brush body is made of non-metallic materials and has considerable quality and strength. It can not only damage the copper conductors, but also can get enough to go. The stained felts should be replaced. Based on this principle, a cleaning device was designed and manufactured.
The cleaning equipment is mainly composed of components such as a base frame, a capping roller, an injection nozzle, an arrow brush assembly cover, a hydraulic system, a pneumatic system, and the like. In operation, the drilled wire 4 is placed flat on the pallet and the hole is closed with a gland. At the end of the wire, place the brush collection cover and place the arrow brush at the end. Then use the gas injection nozzle to inject the compressed air into the wire and blow the arrow brush out from the other end. The arrow brush body can be reused, and the felt can be replaced at any time according to the actual situation. Repeat several arrow brushes to clean when the felt does not see any visible smudges.
2.3 In the hollow wire punching pressure shape, keeping the rectangular cross-sectional shape of the air-cooled turbine rotor coil air duct design, so that each wire coil with the inlet and outlet tongue holes and closed air duct shaped notch . The tongue hole and the shape of the notch tongue are in contact with the opposite edges. The shape notch is punched in the hollow section of the wire and ensures that the cross section of the object is unchanged. It must be carried out in a closed state. equipment.
The punching and pressing equipment consists of the main parts of the hydraulic operating system and the electrical system of the feeding mechanism of the punching head and the centering mechanism of the bed body. The use of program control, sub-adjustment and automatic operation of two functional states. The design of the electro-hydraulic system enables the equipment to effectively avoid quality accidents caused by mis-operation or improper placement of wires and improve the reliability of the equipment. Punching principle 3.
When the vertical clamping block works, adjust the equipment first to match the state of the workpiece. Put a wire flat on the feeding mechanism, send it to the punching press-shaped predetermined position, and then use the two-hand operation keys to release the hand when the person enters the automatic circulation, and the machining process continues until the feeding mechanism returns to the unloading position. The whole process of punching and pressing is as follows: Feeding and feeding mechanism Downwards Horizontal to centering hole Centering punching head Horizontal clamping wire and pressing head Horizontal clamping wire Punching head Vertical clamping wire Pressing head Pressure wire Punching head The front hole is punched and returned to the punching head to punch the back hole and return to the press head and the clamping centering part returns, and the feeding mechanism rises to the discharge position.
2.4 Partial softening and annealing of the copper wire to ensure annealing and non-annealing. The half-coil processing within the transition zone is required within 30. The soft-annealing is performed at both ends of the wire rotor body. The annealing temperature is 550.0 up and down, the hardness is about 40, and the annealing transition area is not More than 30. The ordinary annealing method is difficult to meet these requirements, only rapid heating and cooling. Medium frequency induction heating has the characteristics of rapid temperature rise due to energy concentration, rapid water cooling, and the combination of the two to meet the annealing requirements. Based on this, intermediate frequency annealing equipment was designed and manufactured. Intermediate frequency annealing equipment consists of medium frequency power induction heater cooling system air pressure system and other components. IF power supply is SCR frequency conversion, 8000 output, 1001 input. The cooling water system consists of a water tank, a cooling tank, and a showerhead.
During annealing, the bundle wire is clamped with a special clamp, and is gradually heated inwards from the end by an induction heater matched with the wire bundle. The heating temperature is observed at any time. After reaching the specified position, the heating is stopped immediately, and the water is sprayed to cool down. Below 100, stop the water spray and dry the moisture on the wire with compressed air. At the same time as the spray water is cooled, compressed air is always blown in the wire to prevent moisture from entering the wire.
2.5 The hollow conductor bends 90 bends to avoid invagination and twisting. If the thickness of the inner edge is limited to exceed the permissible value, when the hollow conductor is bent in the free state, the invaginity is easily distorted and the inner edge is excessively thickened. If during bending, the section in the process of deformation is constrained, 4, the inward distortion can be avoided, and the inner edge thickening can be effectively controlled. According to this principle, the curved 90 bend device is mainly composed of the electric control system of the centering device of the hydraulic system vertical pressurization device of the base frame clamping device and the arm. Before bending, first adjust the size of 4 people, according to the actual size of the semi-coil, and then put on the wiring harness, in the wire and the device has a relative movement of the friction area coated with grease, clamping the wire bundle and vertical pressure, steering Rotate the arm slowly to the proper position with the end switch that can adjust the position. Release and remove it. Wipe the grease off with alcohol solvent. The bending is over.
2.6 Forming bends to ensure that the half-span group of rotor coils is formed by welding two half-coil groups. Each half-coil has an accurate end shape and span before the wire is embedded. This requirement is simulated by bending forming equipment. The actual position of the wire in the rotor slot is guaranteed.
The bending forming equipment is composed of a bracket bracket and a clamp force, a radius plate pressure arm sawing centering device hydraulic and electrical control system. When forming, place the 90-turn bent wire harness on the equipment and gently clamp it. At 90 bends, place a compensating gasket between the wires and firmly clamp them. Operate the pressure arm gradually from 9 to bend, and then gradually press down on the bend. Use the special clamp to fix the edge and bend it to the terminal. After bending, release the special clip, correct the angle of the half-coil groove, insert the inter-layer gasket between the ends of the wires, clamp the ends, check the end of the span, and then open the saw to cut the excess. section.
2.7 Connection Processing Two half coils are welded into a set of coils via a connecting piece. The processing of the connection port on the half-coil conductor is the final main process of the rotor coil processing. The main question in connection processing is how to maintain the shape of the end of the half coil and the chip does not fall into the wire. After analysis and test, it is better to use the vertical end to place the milling head downwards. For this purpose, a special saw blade milling machine and special fixtures were designed and manufactured to solve the deformation of the end of the half coil and to prevent the chips from entering the air passage, which greatly facilitated the cleaning of the air passage at the end of the half coil.
2.8 Ensure that the half-coil symmetry and the set of rotor coils are composed of many half-coils. The corresponding half-coils have symmetry and genitality requirements. Half coil surface.
2.8.1 Symmetry of the ventilation holes The symmetry of the ventilation holes means that the ventilation holes at both ends are symmetrical about the axial center of the half coils. The symmetry of the circular ventilation holes is ensured by the CNC vertical machining center. The symmetry of the tongue-shaped ventilation holes is ensured by the centering device of the punching press-shaped equipment. There are two sets of punching heads and press-formed heads, respectively. The device is symmetrically arranged.
2.8.290 Symmetry of the bend The symmetry of the 90 bend means that the 90 bends at both ends are symmetrical relative to the axial center of the half coil, including the position and size of the bend.
The 90 bend position is guaranteed by the equipment. The equipment consists of two bending devices, the middle is connected by a centering device, and the two ends 90 are bent at an angle and finally corrected by the operator through the end point switch.
2.8.3 Half-Coil Coherence The half-coil maneuverability is divided into two aspects: the homogeneity of the same half-coil, which refers to the shape and size of the wires of the same half-coil under the premise of ensuring symmetry; Qualitative refers to the assurance of several aspects of the same scale of equipment and process operations. The wires of the same half coil are combined and then bent, and the half coils of the same size are continuously bent out in the same equipment adjustment state.
2.9 Versatility of the equipment The air-cooled turbo-generator technology introduced by the plant is a serial design. Although there are many varieties of specifications, it can be classified into three series. With the same series of generator rotor coils, the end of the two corners and the formation of bend radius caused by the tongue hole, and the shape of the shape of the size of the recess, but the shape of the position of the recess varies with the coil span. Different series of generator rotor coils are similar This lays a theoretical foundation for the research of rotor coil technology and the selection and development of rotor coil production equipment.
Rotor coil production equipment design, the use of adjustable dual-rail device, to ensure the adjustability of the equipment to meet the needs of different lengths of coil production using interchangeable module structure, the equipment to adapt to different types of rotor coil manufacturing needs.
3 Conclusions Research results of air-cooled turbine rotor coil technology After a year and a half of application, the manufactured air-cooled turbine generator rotor coil meets the requirements of the standard and the quality is stable, which opens up a new way for the manufacture of air-cooled generator rotor coils in the plant. The progress in the manufacturing technology of air-cooled generators in China is of positive significance.
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