Dalan Motor explained the doubts about the insulation of the oil pump motor at a glance!


The most common faults in the use of the motor are winding breakdown, winding short circuit, winding open circuit, winding burnout, etc. These are all motor insulation problems. The length of the motor depends mainly on the insulation quality, and the quality of the insulation of the motor is related to the insulation treatment of the motor, in addition to the insulation structure of the motor. The following questions about motor insulation are explained by Dalan Motors for everyone!

1. What are the aspects of oil pump motor insulation?

Answer: The oil pump motor insulation includes the inter-strand, inter-turn, inter-row, inter-layer and ground-to-ground insulation of the coil, various supporting or fixed permanent insulating members at the end and the insulation of the connecting line and the lead-out line.

2. What is the main insulation of the coil?

Answer: The main insulation of the coil refers to the insulation between the coil and the other windings. It is also called ground insulation.

3. What is the insulation between the turns?

Answer: Inter-turn insulation refers to the insulation between the turns and turns of the same coil.

4. What is inter-strand insulation?

Answer: Inter-strand insulation refers to the insulation between the strands in the same crucible, generally the insulation of the winding wire itself.

5. What is insulation between rows?

Answer: Inter-row insulation is the insulation of several rows of wires in parallel.

6. Why do people compare a coil to the heart of a motor?

Answer: The motor insulation structure acts as a power barrier, but some also act as a mechanical support. The fixed function, during the long-term operation, the motor insulation is affected by electricity, heat, mechanical force and different environmental conditions, and the insulation will gradually age. Ultimately, it loses its proper performance. It causes insulation breakdown and cannot continue safely. Therefore, the reliability and life of the motor 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 for the insulation damage of common motor coils?

Answer: The basic factors of common motor coil insulation damage are heat, electricity, mechanical force and environmental conditions.

8. What are the heat resistance levels of the motor winding insulation?

Answer: The motor winding insulation can be roughly divided into: Class A, Class E, Class B, Class F, Class H and Class C.

9 What is the allowable temperature of the main six heat-resistant grades of the motor winding insulation?

Answer: The allowable temperatures of the six heat-resistant grades are: Class A 105 degrees. Class E 120 degrees. Class B 130 degrees. Class F 155 degrees. Class H 180 degrees. C level is greater than 180 degrees.

10. What are the main factors determining the insulation structure of low-voltage motors?

Answer: Mainly groove shape, welt method, insulation material and insulation treatment process.

11. What is the stator slot shape of small and medium-sized motors? What trough shape is generally used for small and low-voltage motors?

Answer: The stator slot shape of small and medium-sized motors depends on the capacity and voltage and the form of the winding. Small and low-voltage motors generally use semi-closed slots.

12. What does a high voltage motor mean?

Answer: High-voltage motors generally refer to AC motors and generators of 3KV and above.

13. What is the insulation of the high-voltage motor-ring stator coil insulation structure?

Answer: It is mainly to determine the inter-turn insulation, the groove insulation, the end insulation and the lead insulation.

14. What are the three main materials for the main insulation of the high-voltage motor-ring stator coil? What is the main improvement of the main insulation?

Answer: The main insulation is usually composed of mica, reinforcing material and adhesive. The main insulation improvement mainly improves the heat resistance and motor performance of the adhesive.

15. What are the two structural forms of the salient rotor coil of synchronous motor?

Answer: The two structures of the salient-pole rotor coil of synchronous machine are formed, which are multi-layer multi-turn magnetic pole coil and single-layer multi-turn magnetic pole coil.

16. What types of synchronous rotor type rotor coils are there?

Answer: The synchronous machine's hidden pole rotor coil has continuous type, semi-turn type and single layer concentric type.

17. What are the two types of wire-wound type of rotor windings? Which motor is suitable for each?

Answer: The wound rotor winding has two types of in-line and plug-in type. The former is used for small motors and the latter is used for large and medium motors.

18. Insulating varnish can be divided into several categories according to their use?

Answer: Insulating varnish can be divided into impregnating varnish according to its use. Covering lacquer. Guigang lacquer. Enamelled wire lacquer. Adhesive lacquer.

19. What are the two types of insulation impregnating varnishes? What are their advantages and disadvantages?

A: Insulating dip paint can be divided into two types:

1) Solvent insulated impregnating varnish.

2) Solvent-free insulating impregnating varnish. The former has good permeability, long storage period and low price. The advantages of use and production management are convenient, but the paint has the advantages of long drying time when the paint is immersed in the paint, slow evaporation of the solvent, and waste of environment and pollution. The latter has the advantages of fast curing, large viscosity change with temperature, small volatile matter during curing, good dielectric properties of insulation, large amount of paint, etc. However, the paint has the disadvantages of high price, short storage period, large viscosity and complicated production management. .

20. What are the basic principles for the selection of insulating impregnating varnish?

Answer: 1) The viscosity is low, the solid content is high, and it is easy to penetrate and fill the impregnate. The amount of paint to be painted is large. 2) The thick layer of impregnating paint is fast curing, good drying property, strong bonding force, elastic film, and can withstand the centrifugal force when the motor is running. 3) It has good electrical properties, heat resistance, moisture resistance, oil resistance and chemical resistance. 4) It is harmless to conductors and other insulating materials and has good compatibility. 5) The price is cheap, the material is based on domestic, long storage period and low toxicity.

21. What are the basic principles for the selection of insulating cover paint?

Answer: 1) It has a fixed color, and the paint film is smooth, flat, bright and shiny. 2) Highly dispersible. Strong coverage. 3) Long storage period, good stability and no cementation. 4) The paint film has sufficient hardness and wear resistance and good mechanical properties. 5) The paint film has good arc resistance and dielectric properties. 6) The paint film has good moisture resistance, oil proof and chemical corrosion resistance. It should also have anti-toxicity and salt spray resistance for insulating coatings for warm tropical motors. 7) For the special anti-corona cover paint used in high-voltage motors, it also has good resistance stability, uniformity and certain resistance value.

22. What are the two types of epoxy resins commonly used for coil insulation?

A: The commonly used epoxy resins are bisphenol A and phenolic epoxy resins.

23. Which two kinds of curing agents for epoxy resin can be classified according to curing temperature? A: Room temperature curing agent and heat curing agent.

24. What is made of impregnated fiber products?

Answer: Insulating fiber products are used as substrates, and fiber products made of insulating varnish, such as varnish, paint tube and binding tape, etc., are immersed.

25. What are the advantages and disadvantages of fiberglass? What methods are commonly used to improve their shortcomings?

Answer: The advantage is strong tensile strength, high heat resistance and low moisture absorption. The disadvantages are: softness is not good, and it is not resistant to folding. The synthetic fiber is often interwoven or chemically treated to improve its softness and adhesion of the paint film.

26. Which kinds of glass varnishes are commonly used for coil insulation?

Answer: Four kinds of glass cloth are commonly used for coil insulation, namely: 2430 asphaltic alkyd glass cloth, 2432 alkyd glass varnish cloth, 241 polyester glass varnish cloth, and 2450 silicone glass varnish cloth.

27. What material is the insulating paint tube made of? What is its main role?

Answer: The insulating paint tube is made of natural fiber, synthetic fiber or alkali-free glass fiber, and then immersed in insulating paint or resin. It is made by drying and has a certain electromechanical performance and soft paint tube. In the low-voltage coil or winding lead wire, the inter-pole connection line is insulated.

28. What are the paint tubes commonly used in factories?

A: At present, the paint tubes commonly used in factories have 2751 silicon rubber glass paint tubes (H grade insulation) and 2750 silicone glass paint tubes (H grade insulation).

29. How is the laminate made?

Answer: The laminate is a fibrous product substrate, dipped or coated with different adhesives, made into fiber products, and then hot-pressed or rolled into a layered tree insulation material, mainly including laminates and tubes (tubes) ), rods and special profiles.

30. What is the basic media barrier of mica products?

A: It is mica.

31. What are the properties of mica?

A: Mica has good dielectric properties, high heat resistance and chemical stability.

32. Which three kinds of powder mica paper are widely used according to their preparation process?

Answer: 1 cooked powder mica paper, which is a mica paper produced by thermochemical method using mica scrap.

2 Raw mica paper, which is a mica paper produced by applying high-pressure water pulverization method using mica scrap.

3 large scale mica paper, which is a pure mica material, and is made of high-pressure water impact method.

33. What are the advantages of powder mica paper and mica?

A: It has the following advantages:

1 Improve the utilization rate of natural mica, from the original 7% - 10% can increase the energy of more than 80%.

2 The thickness of the powdered mica paper is uniform, and the thickness of the finished product is uniform, so the electrical performance is stable and the thermal conductivity is good.

3 Conducive to the mechanized production of powder mica products, which can improve production efficiency, reduce costs and improve working conditions.

34. What is the main component of mica products?

A: Mainly composed of mica, adhesive and reinforcing materials?

35. There are many varieties of mica products, which can be divided into categories according to their use?

A: According to the use, it can be divided into four types: mica tape, mica plate, mica box and mica glass.

36. Which kinds of electrical film are commonly used for coil insulation? Briefly describe what they have in common? What is their use?

Answer: Commonly used electrical film mainly includes: 6062 polyester film; 6065 polyester imide film and polytetrafluoroethylene film. They have in common the advantages of thin thickness, softness, moisture resistance and good electromechanical properties.

Uses: Mainly used as coil insulation for coils, slot insulation for low voltage motors, etc., and PTFE film is often used as a release material for coil insulation hot press forming.

37. Briefly describe the composition and purpose of composite products?

Answer: The composite product is made of an insulating material by bonding the fiber material on one or both sides of the film for electrical purposes. The purpose is to enhance the mechanical properties of the film, improve the tear strength and surface stiffness to improve the processability.

38. What kinds of common composite products are there?

Answer: Commonly used composite products are: 1, 6520 polyester film insulation paper composite foil. 2, 6530 polyester film glass varnish composite foil. 3, polyester film fat fiber paper composite foil (DMD). 4. Polyester film aromatic polyester amide fiber paper composite foil (NMN). 5. Polyester film sulfone amide polyester non-woven fabric composite foil (SDMSD277). 6. Polyimide film aromatic cluster polyamide fiber paper composite foil (NHN).

39. Which four aspects can be tested for insulation materials according to their performance?

A: According to its performance, it can be divided into four aspects: electrical, mechanical, physical and thermal properties.

40. What are the main contents of the electrical properties of the insulating materials?

A: There are mainly: breakdown strength, volume resistivity, surface resistivity, relative dielectric constant, dielectric loss tangent and corona resistance.

41. What are the basic requirements for DC motor insulation?

Answer: 1. Excellent mechanical properties. 2. Has sufficient electric strength. 3. Has good heat resistance and thermal conductivity. 4. It has good moisture resistance and high thermal insulation resistance.

42. Briefly describe two methods for visual inspection of insulating varnishes?

Answer: 0 test tube method: Pour the paint into a dry, clean and colorless glass test tube with a diameter of 15 mm, and let it stand until the bubbles disappear in the environment; observe the color of the paint under the astigmatism of white enamel, whether it is transparent or not. 0 smear method, take two samples of the paint film before the measurement of electrical properties to observe the color, gloss, mechanical impurities and particles.

43. What is the electrical angle?

A: Electrical angle is a common concept in electrical engineering, and its value is equal to the mechanical angle at 20 degrees.

44. Write the calculation formula for the number of slots per phase per pole and indicate the meaning of each letter in the formula?

45. What are the basic technical requirements for high-voltage motor-ring stator coils?

A: The basic technical requirements are: the number of turns is accurate, and the insulation between the turns is good. 0 is well insulated from the ground. The size and shape of the 0 coil meets the requirements. 0 main insulation should have good welt process performance. 0 meet other special requirements, such as explosion-proof, moisture-proof and mildew-proof.

46. ​​What are the arrangement of the coils of the common ring type high voltage stator coils?

A: The arrangement has a single winding, two rows of several windings, a single row of several windings, a bow-shaped transposition, an N-shaped transposition, a brick arrangement, and the like.

1. Use winding wire insulation to act as turn-to-turn insulation.

2. Intertwinning pad of alkyd silk mica tape.

3. The nose or the whole coil is covered with a layer of mica tape.

4. One and two layers of mica tape per half stack.

5. The arcuate transposition coil is placed at the position of the insulating tube, the N-shaped transposition coil is insulated between the rows, and the soft mica plate is placed at the intersection of the wire and the nose.

47. Why should the coil be shaped? When is it shaped?

A: Coil shaping is to make the shape and related dimensions of the coil meet the design requirements, and the shape of the end of the whole coil is basically the same.

In order to reduce the insulation damage, the shaping is performed after the inter-turn insulation wrap and before the ground insulation wrap.

48. What does the daytime gelation mean? What is the role?

Answer: The inter-turn gelation refers to the hot pressing of the turns of the coil in the straight part of the coil into a solid whole. The function of the coil can meet the requirements of the cross-section of the coil, and the thickness of the main insulation can be ensured, and the rigidity of the coil can be improved. Reduce the distortion of the coil during the manufacturing process.

49. What are the basic requirements for insulation bandaging?

A: 1. The half stack is accurate. 2. The layers are flat and unfolded. 3. The belt tension is appropriate. 4. The direction of the dressing is the same. 5. The number of layers meets the requirements.




----- Editor-in-Chief: Dalan Oil Pump Motor 02-Procurement Consultant

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