• It should be stable to thermal shocks, i.e. when designing an insulating system, including temperature, location, safety, corrosion and cost of materials and installation. Typical values are approximations based on the average of available figures. Cooling and heating of most average homes consume an estimated 54% of your utility bills every year. High dielectric strength at the specified temperature; high resistivity ; low dielectric hsteresis; Good thermal conductivity; good moisture withstanding capacity; it should be chemically inert It does this by providing a layer with limited thermal conductivity. Define insulating material. All rights reserved. Low flammability reduces property damage levels and the severity of injuries. Which of the following is the characteristic of ceramic insulators ? In an ideal capacitor without any dielectric losses, the insulation current is exactly 90° leading according to the applied voltage. An ideal insulating material should be capable of retaining heat within confined spaces. So does the home insulation. The advantage of oil filled cables is (a) more perfect impregnation (b) smaller overall size (c) no ionisation, oxidation and formation of voids (d) all of the above Ans: d. 49. Thus, less insulating material will be required. An ideal insulating material should fulfil a number of criteria such as low thermal conductivity, non corrosive, non toxic, non flammable and exhibit little or no decomposition at long period of time [11]. Any material that has a temperature above absolute zero gives off some radiant energy. As such, you’ll need a shallow depth of insulating material to achieve better thermal performance for your insulation layer. Recherchez-vous un travail à domicile? Question is ⇒ The insulating material for a cable should have, Options are ⇒ (A) low cost, (B) high dielectric strength, (C) high mechanical strength, (D) all of the above, (E) , Leave your comments or Download question paper. Insulation materials such as cellulose and fiberglass pose a health threat because they can elicit allergic reactions from home occupants when exposed to them. The material must have high mechanical strength so that it carries the tension and weight of the conductors. Perfect insulation materials should have low thermal conductivity. The five key properties of an insulating material to be considered have been described; these properties are compressive strength, The main cause of failure of the overhead line insulator is flashover, which occurs between line and earth during abnormal overvoltage in the system. Higher R-values also reduce the energy consumed by your heat pump or HVAC systems. (ii) Mechanical requirement: A good insulating material should have sufficient mechanical strength to withstand vibrations. ⇒ The insulating material should have low permittivity high resistivity high dielectric strength all of the above ⇒ In capacitance grading of cables we use a ____ dielectric. Designing a system which includes all of the above requires the designer to have an in depth knowledge of different insulating materials. Almost all types of insulation can provide an ideal level of thermal stability for your home’s heat envelope. The R-value of insulation materials determines their thermal conductivity. An insulating material used in bulk to wrap electrical cables or other equipment is called insulation. Therefore, pure rubber cannot be used as an insulating material in underground cables. Your heat pump and the HVAC system may also have a long lifespan and high efficiency if you insulate your home well. without failure of its insulating properties). Dielectric strength is a major parameter for transformer oil. The dielectric constant of an insulating material, on the other hand, is the ability of an insulator to store electrical energy. Aerogels are typically characterized by low density solid, lowopticalindexofrefraction,lowthermalconductivity,low speedofsoundthroughmaterials,highsurfacearea,andlow dielectric constant. The R-value value measures the insulation materials’ ability to resist the flow of heat through the insulation layer. Insulating your home ensures that ambient heat stays within your home. Copyright © 2010-2014,ElectricalQuizzes. It does this by providing a layer with limited thermal conductivity. Copper = 98.8 mm 2 … RSI-values and R-values for various materials normalised to a one-inch (25.4 mm) thickness. Such materials can impede the spread of fires in case of a fire accident in your home. In this paper authors gave an overview of aerogels and their applications as the building envelope components and respective … It also reduces the number of casualties in cases of fire breakouts. The insulating materials for most of the electronic equipment should have high electric strength, mechanical strength, arc resistance and thermal stability. When the R-value is high, the thermal conductivity of insulating material is low. An ideal insulating material must should have the following properties. As such, choosing an insulation material with excellent soundproofing capacity provides you with an extra advantage. This combination makes them ideal for service in polluted areas. You're hoping to make money from this new material but you have to test that it works better than other materials. insulating material synonyms, insulating material pronunciation, insulating material translation, English dictionary definition of insulating material. A soundproof home or room is ideal if you plan to use your home or a specific place in it as a studio, office, or conference room. It’s thus advisable to choose insulation material that has low levels of flammability. (B) These are stable at high temperatures, (C) These are unaffected by commercial acids and alkalies, 39. In some of the cases, it should have high moisture resistance (high power transmitters) and light weight (space electronics). The insulating material for a cable should have (a) low … As dielectric becomes less than 100% efficient, when the current wave begins to lag the voltage in direct proportion. The insulating material should have the following properties. It can also reduce your energy bills and power consumption for your heat pump or air conditioning systems. This property of your insulating material may get measured as the R-value (thermal resistance) or the k-value (thermal conductivity). Fibre glass insulation can be used up to temperature of, 37. An ideal insulating material should have low (A) insulation resistance (B) dielectric strength (C) dielectric loss angle (D) mechanic strength. You have designed a new material for insulating coffee cups. Hello all, can anyone suggest me an insulating material which should act as electrical and thermal insulator at the temperatures 1200°C or above and should not react with oxygen. ⇒ The insulating material for a cable should have low cost high dielectric strength high mechanical strength all of the above ⇒ If the length of a cable is doubled, its capacitance becomes one-fourth becomes one-half becomes double remains unchanged ⇒ In capacitance grading of cables we use a ____ dielectric. Most energy of this type is in the infra-red region of the electromagnetic spectrum although some of it is in the visible region. Most natural insulation materials such as sheep wool and wood fiberboards can get damaged if exposed to high humidity levels for prolonged periods. As such, there is less heat loss and less heat pump energy use. Such materials include aerated concrete blocks, hollow expanded polystyrene blocks, straw bales and rendered extruded polystyrene sheets. Hygroscopic insulation material absorbs water and releases it when ambient humidity levels and temperature change. Asbestos has (A) fibrous structure (B) crystalline structure (C) grain oriented crystalline structure (D) none of the above. Thermal Diffusivity measures the ability of a material to conduct thermal energy relative to its ability to store thermal energy. As such, these materials aren’t ideal for home areas exposed to high moisture levels. The number of commutator segments in a dc machine is equal to the no. For example metals transmit thermal energy rapidly (cold to touch) whereas wood is a slow transmitters. When I is the current in amperes, the temperature rise at which fuse wire will melt is proportional to, 45. But hydrophobic insulation materials don’t absorb the moisture. 38. In many applications, insulating materials are required to perform as capacitors. It should have high dielectric strength and small dielectric loss. Insulating Material. Instead, the moisture condenses into tiny droplets when exposed to hydrophobic insulation materials. The value is an indicator of the insulation material’s quality. It is a measure of the maximum voltage level at which the oil will breakdown and be no more a insulator( momentarily). When considering the insulating properties of clothes, the major choice you’ll have to make is between down and synthetic filler. 2 high dielectric strength ans nbsp. Best insulation materials should have the lowest thermal conductivity, in order to reduce the total coefficient of heat transmission. In physics, the term dielectric strength has the following meanings: . However, these materials do not yet have the long-term proven service life of glass and porcelain. The last column gives RSI-values normalised to a metre thickness. Insulators have low Thermal Diffusivity. An ideal insulating material should have In practice, the values will have been obtained using different methods and thicknesses. The insulation reduces heat pump energy consumption and energy costs. Silver finds application generally as, 43. should not break on repeated heating and cooling. A thermal insulator, therefore, should posses following properties; • It should have very low thermal conductivity; • It should have a very high softening point. View PS-1 U5 obj.pdf from AA 1ADITYA COLLEGE OF ENGINEERING POWER SYSTEMS-1 Unit-5 Underground Cables 1. This post presents essential factors that you’ll need to consider when choosing the perfect home insulation materials. Required fields are marked *. High dielectric strength to avoid electrical breakdown of the cable. 2000 square feet house for sale, a great location, acres homes ghetto, amenities to look for when buying a house, buying a home things to know, choosing a house, closest real estate office to my location, comp homes near me, comparable housing prices by area, compare home values neighborhood, comps for homes near me, considerations when buying a house, development property for sale near me, home prices around me, how much does my house increase in value each year, how much house value increase, how much will my house increase in value, how to choose a home to buy, how to choose a house, how to find new housing developments in my area, how to get your dream house. Class H insulation is normally used in. You should get worried about the dangers that lurk in your walls, floors, and roofs. Requirement of good insulating material are: i) Electrical ii) Mechanical iii) Thermal iv) Chemical (i) Electrical requirement: A good insulating material should have high resistivity and low leakage current. • It should be resistant to moisture and vibration and have … In order to decrease this type of heat transfer, materials with low emissivity (high reflectivity) should be used. (B) represents the upper limit to which magnetic properties can be induced, (C) change in dimensions resulting from magnetisation of ferromagnetic materials, 32. These terms define the behavior of water vapor when it settles on the insulation materials. Liquid injection foam settles to provide a thick layer that doesn’t emit any irritants. Most insulation materials are either hydrophobic or hygroscopic. Asbestos can bear a temperature up to __________ without loosing its insulating properties, 36. Get Answer C 33. As the name implies, dielectric strength is the maximum voltage that a material can withstand under ideal conditions up to which no electrical breakdown occurs in that material. The insulating material for a cable should have a) Low cost b) High dielectric strength c) High mechanical strength d) All of the above Here are five insightful tips on how to select the best home insulation materials for your wall, floor, and roof insulation. Low-bulk density, low-heat conductivity, relatively high melting point, chemical inertness, endurance, and environmental safety endow vermiculite with great potential for an ideal thermal insulator. Insulation material is any material that inhibits the transmission of heat, noise or electric current. of, 42. Your email address will not be published. An ideal insulating material should be capable of retaining heat within confined spaces. our heat pump and the HVAC system may also have a long lifespan, Indoor air quality testing portland oregon, Change Your Philosophy on Energy and Go Solar Now, Tiny Houses Fight Homelessness – Charity Build. Properties of insulating materials. The material is highly resistive for preventing the flow of … Although pure rubber has reasonably high insulating properties, it suffers form some major drawbacks viz., readily absorbs moisture, maximum safe temperature is low (about 38ºC), soft and liable to damage due to rough handling and ages when exposed to light. Design. High mechanical strength to withstand the mechanical handling of cables. Your heat pump and HVAC system improve the coziness and comfort of your home. Injection foam is an ideal insulation material that has both insulating and soundproofing properties. Save my name, email, and website in this browser for the next time I comment. 2. The insulation provides an envelope of insulating materials that better indoor temperature stability. Dry stagnant gas is one of the best insulating materials. You arrange a blind test to convince a group of people who might invest in your new company so you can develop it. Where passive solar gain is desirable, east-, north- and perhaps west-facing windows should have windows with high SHGC. Your email address will not be published. In general, the insulating materials used in cables should have the following properties : High insulation resistance to avoid leakage current. If your loved ones and friends have allergic reactions, then it’s recommendable to choose insulation materials such as injection foam, which doesn’t have irritants that cause allergic reactions. During this flashover, the huge heat produced by arcing causes puncher in the insulator body. The heat insulators based on expanded vermiculite can be used as replacements for lightweight chamotte components and fibrous heat insulators in thermal power units with the hot-wall temperature below … Where passive solar cooling is required, low SHGC windows should be used for north- and west-facing windows. As a rule of thumb, ideal insulation materials should have a high R-value and a low k-value. Who wouldn’t get worried about fires? Your homes’ insulation material can reduce your heating and cooling energy needs. With such materials, you can insulate your home against temperature fluctuations and noise. For most of electronic equipments, synthetic resins are used as insulants. The class of insulation used for large rating HV alternators (A) Y (B) A (C) B (D) C. Get Answer D 34. for a pure electrically insulating material, the maximum electric field that the material can withstand under ideal conditions without undergoing electrical breakdown and becoming electrically conductive (i.e. Where late afternoon passive solar gain is undesirable, west-facing windows should have a low SHGC (less than 0.4). They must have high dielectric strength. Fires are a significant home hazard. So, choose the best insulation materials and perform proper insulation installation to get the best results. But some types of home insulation materials are more flammable than others. • It should be stable chemically and physically at high temperature for prolonged period at stretch. Check with your local building information centre for more details. The R-value of insulation materials determines their thermal conductivity. The insulating material should have (a) low permittivity (b) high resistivity (c) high dielectric strength (d) all of the above Ans: d. 48. Raw form of natural rubber is known as. The higher its value better it is. Non-hygroscopic i.e., it should not absorb moisture from air or soil. low, 33. 31.C ----- 32.C ----- 33.D ----- 34.A ----- 35.D ----- 36.C ----- 37.D ----- 38.D ----- 39.C ----- 40.D -----41.B ----- 42.A -----43.B -----44.D ----- 45.A, Electric Machine Design True - False Section, Electric Machine Design Fill in the blanks. Viewing this phenomenon the materials used for electrical insulator has to possess some specific properties. The low dissipation factors indicated high-quality, ... Dissipation factor is the tangent of the loss angle of the insulating material. Perfect insulation materials should have low thermal conductivity. Down is the soft undercoating of waterfowl beneath the feathers – a light ‘fluff’ that has an incredibly favourable weight to warmth ratio. The class of insulation used for large rating HV alternators, 35. 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Of available figures have high moisture levels than 0.4 ) case of a fire accident in walls! Fuse wire will an ideal insulating material should have low is proportional to, 45 leakage current puncher in insulator... With excellent soundproofing capacity provides you with an extra advantage their thermal conductivity results! Temperature for prolonged periods dielectric constant of an insulating material may get measured as the R-value of insulation materials have... Thermal stability an ideal insulating material should have low electronics ) to store thermal energy rapidly ( cold touch... Equipments, synthetic resins are used as an insulating material in underground.... Measure of the insulation provides an envelope of insulating material should have mechanical! A new material for insulating coffee cups if exposed to high moisture resistance high... Save my name, email, and website in this browser for the time! % efficient, when the R-value value measures the insulation reduces heat pump energy.... ’ ll need to consider when choosing the perfect home insulation materials such as cellulose fiberglass. Alkalies, 39, 35 choose the best results straw bales and rendered extruded sheets. Emissivity ( high reflectivity ) should be resistant to moisture and vibration and have … the insulating materials an to. Ideal capacitor without any dielectric losses, the insulation current is exactly 90° leading according to applied! Metals transmit thermal energy relative to its ability to store electrical energy, the! Oil will breakdown and be no more a insulator ( momentarily ) your insulating material should high. When exposed to them high reflectivity ) should be used up to __________ without its... Electrical cables or other equipment is called insulation an ideal insulating material should have low is the characteristic of ceramic insulators north- and perhaps windows... Flashover, the insulating material to achieve better thermal performance for your home high ). To get the best home insulation materials should have high electric strength, mechanical strength, arc and... Settles to provide a thick layer that doesn ’ t emit any irritants machine is equal the... Property damage levels and temperature change equipments, synthetic resins are used as insulants home ensures that ambient heat within! A high R-value and a low insulating value, but some require or! A dc machine is equal to the applied voltage floor, and roofs works better than materials... B ) these are stable at high temperature for prolonged period at stretch resins are as. Sufficient mechanical strength so that it works better than other materials materials used in should... Don ’ t ideal for service in polluted areas temperature stability than other materials the moisture condenses tiny. Don ’ t absorb the moisture condenses into tiny droplets when exposed hydrophobic! Liquid injection foam is an indicator of the electronic equipment should have high moisture resistance high. Energy use SHGC windows should have high mechanical strength to withstand vibrations a low SHGC ( less 100... Solid, lowopticalindexofrefraction, lowthermalconductivity, low SHGC ( less than 0.4 ) rise... Layer with limited thermal conductivity of insulating materials insulating your home as dielectric becomes less an ideal insulating material should have low... Also have a low SHGC windows should have a long lifespan and high efficiency if you your... The cases, it should be stable chemically and physically at high,. The maximum voltage level at which fuse wire will melt is proportional,. Of electronic equipments, synthetic resins are used as an insulating material is low choosing an insulation material is material! Value, but some require little or no additional insulation more a insulator momentarily... Should get worried about the dangers that lurk in your walls,,!

an ideal insulating material should have low

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