Electric Motor is good or not ? It must look at the insulation line: counting electric motor insulation 50 questions as follows;
Q 1: What does motor insulation include?
motor insulation includes inter-strand, inter-turn, inter-row, interlayer and ground insulation of coils, various insulating components used for various supports or fixing at the ends, and insulation of connecting wires and lead wires.
Q 2: When is the main insulation of the coil?
The main insulation of the coil refers to the insulation between the coil and other windings, which is also called ground insulation.
Q 3: When is turn-to-turn insulation?
Inter-turn insulation refers to the insulation between turns and turns of the same coil.
Q 4: How are laminates made?
Laminated products are laminated trees made of fiber products from the substrate of fiber products, soaked or coated with different adhesives, and then hot-pressed or rolled into layered knotted insulating materials, mainly including laminates, tubes (tubes), rods and special profiles.
Q 5: What are the commonly used paint tubes?
Commonly used paint tubes are 2751 silicone rubber edge glass paint pipe (class H insulation) and 2750 silicone glass paint pipe (class H insulation).
Q 6: What material is the insulating paint tube made of? What is its main role?
The insulating paint pipe is a kind of soft paint pipe with certain mechanical and electrical properties made by drying natural fiber, synthetic fiber or alkali-free glass fiber woven into a tube, and then impregnated with insulating paint or resin, which is mainly used for the lead wire of low-voltage coil or winding, and the insulation of the connecting wire between the poles.
Q 7: What kinds of glass paint cloths are commonly used for coil insulation?
There are 4 kinds of glass cloth commonly used for coil insulation, namely: 2430 asphalt alkyd glass cloth, 2432 alkyd glass paint cloth, 241 polyester glass paint cloth, and 2450 silicone glass paint cloth.
Q 8: What are the advantages and disadvantages of fiberglass? What are the common ways to improve its shortcomings?
Advantages: strong tensile resistance, high heat resistance, and low moisture absorption. Its disadvantages are: poor softness, not resistant to folding, often synthetic fibers to interweave or chemical treatment methods to improve its softness and adhesion of the paint film.
Q 9: What are impregnated fiber products made of?
Fiber products made of insulating fiber products as the substrate and impregnated with insulating varnish, such as lacquered cloth, paint pipe and lashing belt.
Q 10: What are the two types of curing agents for epoxy resins according to the curing temperature?
Room temperature curing agents and heat curing agents.
Q 11: What are the two types of epoxy resins commonly used for coil insulation?
Commonly used epoxy resins are bisphenol A and phenolic epoxy resins.
Q 12: What are the basic principles for the selection of insulating covering paints?
(1) It has a fixed color, and the paint film is smooth, flat, bright and shiny.
(2) It has a high degree of dispersion. The coverage should be strong.
(3) Long storage period, good stability, 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-proof, oil-proof, and chemical-resistant, and should also have anti-toxicity and anti-salt spray for insulating covering paint for warm tropical motors.
(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.
Q 13 : What are the basic principles for the selection of insulating impregnating paints?
(1) The viscosity should be low and the solid content should be high, which is convenient for penetration and filling of impregnated matter. The amount of paint hung should be large.
(2) The thick layer of impregnating paint cures quickly, has good dryness, strong adhesion, elasticity of the paint film, and can withstand the centrifugal force when the motor is running.
(3) It has 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.
(5) The price is cheap, the material is based on China, the storage period is long and the toxicity is small.
Q 14: What are the two types of insulating impregnating paints? What are their advantages and disadvantages?
Insulating impregnating varnish can be divided into two types:
(1) Solvent insulating impregnating paint.
(2) Solvent-free insulating impregnating paint.
The former has good permeability, a long storage period, and is cheap. It has the advantages of convenient use and production management, but the paint has the disadvantages of long drying time and slow curing when dipping the workpiece, and the volatilization of the solvent causes waste and pollution of the environment. The latter has the advantages of fast curing, large viscosity change with temperature, small volatiles in the curing process, good insulating dielectric properties, and large amount of hanging paint, but the paint has the disadvantages of high price, short storage period, large viscosity, and complex production management.
Q 15: How many types of insulating varnish can be divided into according to their use?
Insulating paint can be divided into impregnating paint, covering paint, Guigang sheet paint, enameled wire paint, adhesive paint, etc.
Q 16: What are the two types of wire embedding for Rao linear rotor windings? What kind of motors are they suitable for?
There are two types of embedded wire windings, the former is used for small motors, and the latter is used for medium and large motors.
The hidden rotor coil of the synchronous machine is available in continuous, half-turn and single-layer concentric.
Q 18: What are the two structural forms of salient rotor coils for synchronous motors?
The two structures of the salient pole rotor coil of the synchronous machine are multi-layer multi-turn pole coil and single-layer multi-turn pole coil.
Q 19： What are the three materials that are usually composed of the main insulation of the stator coil of a high-voltage motor? What is the main improvement of the main insulation?
The main insulation is usually composed of three materials: mica, reinforcing material and adhesive, and the main insulation improvement mainly improves the heat resistance of the adhesive and the motor performance.
Q 20: What are the main types of insulation to determine the insulation structure of the high-voltage motor coil stator coil?
It is mainly to determine the inter-turn insulation, slot insulation, end insulation and lead insulation.
Q 21: What does a high voltage motor mean?
High-voltage motors generally refer to AC motors and generators of 3KV and above.
Q 22: What does the stator slot shape of small and medium-sized motors depend on? What kind of slot is generally used in small low-voltage motors?
The stator groove of small and medium-sized motors depends on the capacity, voltage and winding form, and small low-voltage motors generally use semi-closed grooves.
Q 23 : What are the main factors that determine the insulation structure of low-voltage motors?
It is mainly trough, wire embedding, insulation material and insulation treatment process.
Q 24 : What are the general heat resistance grades of motor winding insulation?
The insulation of motor windings can be roughly divided into: Class B, Class F, Class H, Class C.
Q 25 : Why do people compare the coil to the heart of a motor?
In the process of long-term operation, the motor insulation is affected by the action of electricity, heat, mechanical force and different environmental conditions, the insulation will gradually age, and eventually lose its due performance, resulting in insulation breakdown, can not continue to be carried out safely, so the reliability and life of the motor operation are largely determined by the coil insulation, so people compare the coil to the heart of the motor.
Q 26 : What is inter-row insulation?
Inter-row insulation is the insulation of several rows of wires in parallel.
Q 27 : What is interthigh insulation?
Interstrand insulation refers to the insulation between strands in the same turn, generally the insulation of the winding magnet wire itself.
Q 28: What is the basic medium barrier for mica products?
It's mica.
Q 29 : What are the properties of mica?
Mica has good insulating dielectric properties, high heat resistance, and chemical stability.
Q 30 : What are the three types of powder mica paper that are widely used at present, according to their different preparation processes?
(1) Cooked powder mica paper, which is a powder mica paper produced by thermochemical methods using mica scraps.
(2) Cornstarch mica paper, which is a powdered mica paper produced by using mica scrap and applying high-pressure water crushing method.
(3) Large flake mica paper, which is pure mica material, and the flake larger powder mica paper produced by high-pressure water impact method.
Q 30 : What are the advantages of pink mica paper compared to sheet mica?
It has the following advantages:
(1) Improve the utilization rate of natural mica, from the original 7%-10% can increase the energy by more than 80%.
(2) The thickness of the powder mica paper is uniform, and the thickness of the finished products is uniform, so the electrical properties are stable and the thermal conductivity is good.
(3) It is conducive to the mechanized production of powder mica products, which can improve production efficiency, reduce costs and improve labor conditions.
Q 31: What are the main components of mica products?
It is mainly composed of mica, adhesive and reinforcing materials.
Q 32 :There are many varieties of mica products, which categories can be divided into according to their use?
According to the use, it can be divided into four categories: mica tape, mica plate, mica box and mica glass.
Q 33: What kinds of electrical films are commonly used for coil insulation? What do they have in common? What are they used for?
Commonly used electrical films mainly include: 6062 polyester film; There are three kinds of 6065 polyesterimide film and PTFE film. What they have in common is that they are thin, soft, moisture-resistant, and have good electromechanical properties. Uses: Mainly used as coil wrapping insulation, low-voltage motor slot insulation, etc., and PTFE film is often used as a release material for coil insulation hot pressing molding.
Q 34: Briefly describe the composition and purpose of composite products?
Composite products are made of insulating materials by bonding one or both sides of electrical film with fiber materials, the purpose of which is to enhance the mechanical properties of the film, improve the tear strength and surface stiffness to improve the use of manufacturability.
Q 35: What are the commonly used composite products?
Commonly used composite products are:
(1) 6520 polyester film insulating paper composite foil.
(2) 6530 polyester film glass paint cloth composite foil.
(3) Polyester film, lipid fiber paper composite foil (DMD).
(4) Polyester film aromatic polyamide fiber paper composite foil (NMN).
(5) Polyester film sulfoneamide polyester non-woven composite foil (SDMSD277).
(6) Polyimide film, aromatic cluster, polyamide fiber paper, composite foil (NHN).
Q 36 : What are the four aspects of the inspection items of insulating materials according to their performance?
According to its performance, it can be divided into four aspects: electrical, mechanical, physical and chemical and thermal properties.
Q 37: What are the main contents of testing the electrical properties of insulating materials?
Mainly: breakdown strength, volume resistivity, surface resistivity, relative dielectric constant Lou, dielectric loss tangent and corona resistance and other items.
Q 38: Write out three basic formulas for the determination of the composition content of mica products? And mark the meaning of the letters in each formula?
(1) Volatile content X(%)X=(G-G1)/Gx100%;
(2) Adhesive content Y(%)Y=(G1-G2)/G1x100%;
(3)Z=100%-(Y+KxKxFxD)/G1x100%;
here :
G - sample weight before drying (g)
G1 - Sample weight after drying (g)
G2 - Specimen weight after burning
K——Glass cloth weight(g/m²)
F – Specimen area (m²)
D - the number of reinforcement layers.
Q 39 : Briefly describe the two appearance inspection methods of insulating paint?
Test tube method: pour the paint into a dry, clean and colorless glass test tube with a diameter of 15mm, and let it stand in the environment until the bubbles disappear; Observe the color of the lacquer under the light during the daytime astigmatism, whether it is transparent or not.
Smear method: take two samples of the paint film before measuring the electrical properties to observe the color, gloss, whether there are mechanical impurities and particles of the paint film.
Q 40 : What are the basic technical requirements for the coil-type stator coil of high-voltage motors?
The number of turns is accurate, and the inter-turn insulation is good. Good insulation to the ground. The size and shape of the coil meet the requirements. The main insulation should have good performance of the wire embedding process. Meet other special requirements, such as explosion-proof, moisture-proof and mildew-proof, etc.
Q 41: What are the types of wire turns of common coil high-voltage stator coils?
The arrangement forms include single winding, double row of several parallel winding, single row of several parallel winding, bow transposition, N-shaped transposition, brick arrangement, etc.
Q 42: What are the types of interturn structures of coil high-voltage stator coils?
There are usually the following types:
(1) Use winding wire insulation as inter-turn insulation.
(2) Inter-turn pad gold film pad.
(3) The nose or the whole coil septum is half-stacked with a layer of mica tape.
(4) Pack 1 to 2 layers of mica tape per turn of semi-stack.
(5) The bow transposition coil is sleeved with an insulating tube, the N-shaped transposition coil is insulated between the rows, and the intersection of the wire turn and the nose is padded with a soft mica plate.
Q 43: Why do coils need to be shaped? When is it reshaped?
The purpose of coil shaping is to make the shape and size of the coil meet the design requirements, and make the end shape of the whole coil basically consistent. In order to reduce insulation damage, shaping is performed after the inter-turn insulation wrapping and before the ground insulation wrapping.
Q 44 : What is inter-turn gelatinization? What does it do?
Inter-turn gelatinization refers to the hot pressing of each turn of the wire in the straight part of the coil into a strong whole, which can make the cross-sectional size of the coil meet the requirements, provide guarantee for the thickness and size of the main insulation, and improve the stiffness of the coil and reduce the deformation of the coil in the manufacturing process.
Q 45 : What are the basic requirements for insulating tape wrapping?
(1) Half-stacked packs are accurate.
(2) The layers are flat and unfolded.
(3) The tension of the strap is appropriate.
(4) The bandaging direction is the same.
(5) The number of layers meets the requirements.
Q 46 : What are the two methods of wrapping lead insulation?
One is to wrap the lead insulation first, and then wrap the end insulation, and the other is to wrap the lead insulation in the main insulation process of the end of the wrapper.
Q 47 : What is Insulation Lap? How many lap methods are there?
When the insulation lap is wrapped with two materials for the groove insulation and the end insulation of the coil stator coil, the two materials should be lapped at a certain position, that is, the insulation lap, and the coil is wrapped in insulation lap and wrapped insulation lap.
Q 49 : Where to find professional electric motor manufacturer in China
Dongchun motor is a good choice for you , it is a professional electric motor manufacturer in China
Q 50 : About Dongchun Motors
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