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1.What aspects does motor insulation include?
Answer: The motor insulation includes the insulation between strands, turns, rows, layers and ground of the coil, various insulating components used for supporting or fixing the ends, and the insulation of connecting wires and lead wires.2. When is the main insulation of the coil?Answer: The main insulation of the coil refers to the insulation between the coil and the body and other windings. It is also commonly called ground insulation.3. When is the inter-turn insulation required?Answer: Turn-to-turn insulation refers to the insulation between turns of the same coil.4. When should the strands be insulated?Answer: Inter-strand insulation refers to the insulation between strands in the same turn, generally the insulation of the winding electromagnetic wire itself.5.What is inter-row insulation?Answer: Inter-row insulation is the insulation of several rows of wires connected in parallel.6.Why do people compare the coil to the heart of the motor?Answer: The motor insulation structure plays the role of insulation, but some also play a role in mechanical support and fixation. During long-term operation, the motor insulation is affected by electricity, heat, mechanical force and different environmental conditions, and the insulation will gradually age. Eventually it loses its proper performance, leading to insulation breakdown, and cannot continue to operate safely. Therefore, the reliability and lifespan of the motor's operation are largely determined by the insulation of the coil, so people compare the coil to the heart of the motor.7. What are the basic factors that cause insulation damage to commonly used motor coils?Answer: The basic factors that cause insulation damage to commonly used motor coils include heat, electricity, mechanical force and environmental conditions.8. What are the general heat-resistant grades of motor winding insulation?Answer: Motor winding insulation can be roughly divided into: Class B, Class F, Class H, and Class C.9. What are the main factors that determine the insulation structure of low-voltage motors?Answer: Mainly groove shape, wire embedding method, insulation material and insulation treatment process.10. What determines the slot shape of the stator of small and medium-sized motors? What slot shape is generally used in small and low-voltage motors?Answer: The stator slot shape of small and medium-sized motors depends on the capacity, voltage and winding form. Small and low-voltage motors generally use semi-closed slots.11.What does high voltage motor mean?Answer: High-voltage motors generally refer to AC motors and generators of 3KV and above.12. What are the main insulation structures of the high-voltage motor coil stator coil insulation structure?Answer: The main thing is to determine the insulation between turns, slot insulation, end insulation and lead insulation.13. What three materials are the main insulation of high-voltage motor coil stator coils usually made of? What are the main improvements in main insulation improvements?Answer: Main insulation is usually composed of three materials: mica, reinforcing material and adhesive. Main insulation improvement mainly improves the heat resistance and motor performance of its adhesive.14.What are the two structural forms of salient pole rotor coils of synchronous motors?Answer: There are two structures of salient pole rotor coils of synchronous machines, which are multi-layer multi-turn magnetic pole coils and single-layer multi-turn magnetic pole coils.15.What are the types of hidden pole rotor coils of synchronous machines?Answer: Synchronous machine hidden pole rotor coils include continuous type, half-turn type and single-layer concentric type.16．What are the two wire embedded forms of linear rotor windings? What kind of motors are they suitable for?Answer: There are two types of embedded rotor windings: scattered embedded type and plug-in type. The former is used for small motors, and the latter is used for medium and large motors.17.How many categories can insulating paint be divided into according to its usage?Answer: Insulating paint can be divided into impregnating paint, covering paint, Guigang flake paint, enameled wire paint, adhesive paint, etc. according to its use.18. What are the two categories of insulating impregnating paint? What are their advantages and disadvantages?Answer: Insulating impregnating paint can be divided into two types:①There is solvent insulating impregnating paint.②Solvent-free insulating impregnating paint. The former has good permeability, long storage period and low price. It has the advantages of convenient use and production management, but the paint has the disadvantages of long baking time and slow curing when dipping workpieces into paint, and the volatilization of the solvent causes waste and environmental pollution. The latter has the advantages of fast curing, large viscosity changes with temperature, small volatiles during the curing process, good insulation and dielectric properties, and a large amount of paint. However, the paint has disadvantages such as high price, short storage period, high viscosity, and complex production management. .19. What are the basic principles for selecting insulation impregnating paint?Answer: ① The viscosity should be low and the solid content should be high to facilitate penetration and filling of impregnated materials. The amount of paint to be hung should be large.②Thick layers of impregnated paint cure quickly, have good drying properties, strong adhesion, the paint film is elastic, and can withstand the centrifugal force when the motor is running.③Has good electrical properties, good heat resistance, moisture resistance, oil resistance and chemical resistance.④ It is harmless to conductors and other insulating materials and has good compatibility.⑤The price is cheap, the materials are domestically produced, the storage period is long and the toxicity is low.20. What are the basic principles for selecting insulation covering paint?Answer: ① It has a fixed color, and the paint film is smooth, flat, bright and shiny.②Has a high degree of dispersion. The coverage should be strong.③Long storage period, good stability and no cementing phenomenon.④The paint film has sufficient hardness and wear resistance, and good mechanical properties.⑤The paint film has good arc resistance and dielectric properties.⑥The paint film has good moisture-proof, oil-proof, and chemical corrosion resistance. For insulating covering paint for motors in warm zones, it should also be anti-toxic and salt-spray proof.⑦; For the special anti-corona covering paint used in high-voltage motors, it also has good resistance stability, uniformity and a certain resistance value. 21. What are the two types of epoxy resins commonly used for coil insulation?Answer: Commonly used epoxy resins are bisphenol A and phenolic epoxy resins.22. Which two types of curing agents for epoxy resin can be divided into based on curing temperature?Answer: Room temperature curing agent and heating curing agent.23. What are impregnated fiber products made of?Answer: Fiber products made of insulating fiber products as the base material and dipped in insulating paint, such as varnished cloth, paint tubes and strapping tapes.24. What are the advantages and disadvantages of fiberglass? What methods are commonly used to improve its shortcomings?Answer: Advantages include strong tensile strength, high heat resistance and low moisture absorption. Its disadvantages are: poor softness and not resistant to folding. Synthetic fibers are often interwoven or chemically treated to improve its softness and adhesion of the paint film.25. What kinds of glass varnish are commonly used for coil insulation?Answer: There are four commonly used glass cloths for coil insulation, namely: 2430 asphalt alkyd glass cloth, 2432 alkyd glass varnish cloth, 241 polyester glass varnish cloth, and 2450 silicone glass varnish cloth.26. What material is the insulating paint tube made of? What is its main function?Answer: The insulating paint tube is made of natural fibers, synthetic fibers or alkali-free glass fibers woven into a tube shape, then impregnated with insulating paint or resin, and dried to make a soft paint tube with certain mechanical and electrical properties. It is mainly used. For the lead wires of low-voltage coils or windings, the connecting wires between poles are insulated.27. What are the commonly used paint tubes?Answer: Commonly used paint tubes include 2751 silicone rubber-rimmed glass paint tube (H-class insulation) and 2750 organic silicon glass paint tube (H-class insulation).28. How are laminates made?Answer: Laminated products are fiber products that are dipped or coated with different adhesives as a base material, and are then hot-pressed or rolled into layered tree-shaped insulating materials. They mainly include laminates, tubes (cylinders) ), rods and special profiles, etc. 30. What is the basic dielectric barrier of mica products?31. What properties does mica have?Answer: Mica has good insulating dielectric properties, high heat resistance and chemical stability.32. What are the three types of powdered mica papers currently widely used according to their different preparation processes?Answer: ①Cooked powdered mica paper, which is powdered mica paper produced by thermochemical method using mica scraps.② Raw mica paper, which is produced by using mica scraps and applying high-pressure water crushing method.③ Large scale mica paper, which is pure mica material, is a powdery mica paper with larger scales produced by high-pressure water impact method.33. Compared with flake mica, what are the advantages of pink mica paper?Answer: It has the following advantages:① Improve the utilization rate of natural mica, from the original 7% to 10%, the performance can be increased by more than 80%.②The thickness of powdered mica paper is uniform, and the thickness of the products made is uniform, so the electrical properties are stable and the thermal conductivity is good.③ It is conducive to the mechanized production of powdered mica products, which can improve production efficiency, reduce costs and improve working conditions.34. What do mica products mainly consist of?Answer: Mainly composed of mica, adhesive and reinforcing materials?35. There are many varieties of mica products. Which categories can they be divided into according to their uses?Answer: According to use, it can be divided into four categories: mica tape, mica plate, mica box and mica glass.37. What kinds of electrical films are currently commonly used for coil insulation? Briefly describe what they have in common? What are their uses?Answer: Commonly used electrical films mainly include: 6062 polyester film; 6065 polyesterimide film and polytetrafluoroethylene film. What they have in common is that they are thin, soft, moisture-resistant, and have good electromechanical properties.Usage: Mainly used as wrapping insulation of coils, slot insulation of low-voltage motors, etc. PTFE film is often used as a release material for hot pressing molding of coil insulation.38. Briefly describe the composition and purpose of composite products?Answer: Composite products are insulation materials made by bonding electrical films with fiber materials on one or both sides. The purpose is to enhance the mechanical properties of the film, improve the tear strength and surface stiffness to improve the use process.39. What are the commonly used composite products?Answer: Commonly used composite products include:①6520 polyester film insulating paper composite foil.②6530 polyester film glass varnish cloth composite foil.③Polyester film, fat fiber paper composite foil (DMD).④Polyester film aromatic polyamide fiber paper composite foil (NMN).⑤Polyester film sulfone amide polyester non-woven composite foil (SDMSD277).⑥Polyimide film aromatic cluster polyamide fiber paper composite foil (NHN).40. In what four aspects can the inspection items of insulation materials be divided according to their performance?Answer: According to its performance, it can be divided into four aspects: electrical, mechanical, physical and chemical and thermal properties.41. What are the main contents of testing the electrical properties of insulating materials?Answer: Mainly include: breakdown strength, volume resistivity, surface resistivity, relative dielectric constant, dielectric loss tangent and corona resistance.42. Write down the three basic calculation formulas for determining the component content of mica products? And mark the meanings of the letters in each formula?Answer: ① Volatile content X (%) X = (G-G1)/Gx100%②Adhesive content Y (%) Y = (G1-G2)/G1x100%③Mica content Z (%) Z＝100%-(Y+KxKxFxD)/G1x100%Where G——sample weight before drying (g) G1——Weight of sample after drying (g) G2——sample weight after burning (g) K——standard weight of glass cloth (g/m²) D——number of reinforcement layers.43. Briefly describe the two appearance inspection methods of insulating paint?Answer: Test tube method: Pour the paint into a dry, clean and colorless glass test tube with a diameter of 15mm.Let it stand in the environment until the bubbles disappear; observe the color of the paint under daylight astigmatism to see if it is transparent. 0 smear method, take two paint film samples before measuring the electrical properties to observe the color, gloss, and presence of mechanical impurities and particles of the paint film.44. What are the basic technical requirements for high-voltage motor coil stator coils?Answer: The number of turns is accurate and the insulation between turns is good.Good insulation from ground. The size and shape of the coil meet the requirements.The main insulation should have good wire embedding process performance.Meet other special requirements, such as explosion-proof, moisture-proof and mildew-proof, etc.45. What are the common turn arrangements of coil-type high-voltage stator coils?Answer: The arrangement forms include single winding, double row of several poles and parallel winding, single row of several poles and parallel winding, bow-shaped transposition, N-shaped transposition, brick-shaped arrangement, etc.46. What are the types of inter-turn structures of coil-type high-voltage stator coils?Answer: Usually there are the following types:① Use winding wire insulation as inter-turn insulation.②Place gold film pads between turns.③ Wrap a layer of mica tape on the nose or full coil half-stacked every other turn.④ Wrap 1 to 2 layers of mica tape per half turn.⑤The transposition of the arcuate transposition coil is covered with an insulating tube, the N-shaped transposition coil is insulated between rows, and the intersection of the wire turns and the nose is padded with a soft mica board.47. Why does the coil need to be shaped? When should it be shaped?Answer: Coil shaping is to make the shape and relevant dimensions of the coil meet the design requirements, and to make the end shape of the entire coil basically the same. In order to reduce insulation damage, shaping is performed after the insulation between turns is wrapped and before the insulation is wrapped to the ground.48. What does inter-turn gelling mean? What is its function?Answer: Inter-turn gelling refers to hot-pressing the turns of the wires in the linear part of the coil into a solid whole. Its function can make the cross-sectional size of the coil meet the requirements, provide guarantee for the thickness of the main insulation, and improve the stiffness of the coil. Reduce coil deformation during manufacturing.49. What are the basic requirements for wrapping with insulation tape?Answer: 1. Half stacked package is accurate. 2. The layers are smooth without folds. 3. The strap tension is appropriate. 4. The bandaging direction is the same. 5. The number of layers meets the requirements.50. What are the two methods of insulating lead wires?Answer: One way to wrap the lead insulation is to wrap the lead insulation first, and then wrap the end insulation. The other is to wrap the lead insulation during the main insulation wrapping process of the end.51. What is insulation overlapping? What are the several overlapping methods?Answer: Insulation overlap is when the slot insulation and end insulation of the coil stator coil are wrapped with two materials. The two materials should be overlapped at a certain position, that is, insulation overlap. The insulation overlap and winding are divided into rolls. Includes two types of insulation overlap.
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