insulation and cooling
Description : Transformer oil is used as ________. A. Doping Element B. Coolant C. Power booster D. None
Last Answer : Transformer oil is used as Coolant.
Description : Which kind of liquid is not used as transformer oil? A. Mineral Oil B. Silicon liquids C. Nitrogen Liquids D. Hydrocarbon liquids
Last Answer : Nitrogen Liquids is not used as transformer oil.
Description : What is the function of oil in transformer ?
Last Answer : The job of transformer oil is to cool the transformer. So that the transformer does not get hot and burn.
Description : What is the weight of one gallon of transformer oil?
Last Answer : 7.6 pounds/gallon
Description : Stones are provided in the substation to: a) To avoid fire accident by draining oil from transformer if leaks b) To avoid growing of weeds and plants c) To provide insulation d) All the above
Last Answer : Ans: D
Description : Figure 'B' shown in the illustration represents a/an ____________. EL-0091 A. magnetic amplifier B. Scott-T transformer C. saturable-core reactor D. oil-filled toroid
Last Answer : Answer: A
Description : Figure 'A' shown in the illustration represents a/an _______________. EL-0091 A. magnetic amplifier B. Scott-T transformer C. saturable-core reactor D. oil-filled toroid
Last Answer : Answer: C
Description : Which type of oil is used as a transformer oil?
Last Answer : Transformer oil, or insulating oil, is usually a highly-refined mineral oil that is stable at high temperatures and has excellent electrical insulating properties. It is used in oil filled ... life, readily biodegradable, and have a lower volatility and higher flash points than mineral oil.
Description : What is the function of transformer oil?
Last Answer : A. Transformer Oil serves mainly two purposes 1. It acts as liquid insulation in electrical power transformer 2. It dissipates heat of the transformer i.e acts as coolant. In addition to these ... acid (C7, C8) esters are also becoming increasingly common as alternatives to naphthenic mineral oil.
Description : Why transformer oil is used as a cooling medium?
Last Answer : When transformer oil is used as a coolant the heat dissipation by convection is 10 times more than the convection due to air. Hence transformer oil is used as a cooling medium.
Description : What is the function of transformer oil in a transformer ?
Last Answer : Transformer oil provides , (i)good insulation and (ii)cooling . Nowadays instead of natural mineral oil, synthetic oils known as ASKRELS (trade name ) are used. They are non-inflammable ... an electric arc do not decompose to produce inflammable gases. PYROCOLOR oil possess high dielectric strength.
Description : What is oil immersed type transformer?
Last Answer : In this type of transformer, oil is used as coolant. Entire assembly including core and windings is kept immersed in oil. The developed heat is transferred to the walls of tank through oil. Finally the heat is transferred to the surrounding air from tank wall by radiation.
Description : Which of the following tests is not done for transformer oil? (A) Flash point and acid value (B) Aniline point (C) Dielectric strength (D) Copper strip corrosion test
Last Answer : (B) Aniline poin
Description : What are the types of oil used for in transformer for cooling?
Last Answer : Paraffin based and naphtha based (in INDIA)
Description : Why there is no mixing of oil of tap changer and transformer?
Last Answer : When the tap changing takes place arc is struck between the contacts. Due to this the oil inside the tap changer will be highly carbonised. If both oil get mixed up the quality of transformer tank oil will come down. This is not advisable. Hence both oils are kept separately.
Description : What is the requirement oil in a transformer?
Last Answer : Oil is used removal of heat produced in the transformer and also as insulating medium.
Description : Mention the properties of transformer oil.
Last Answer : Properties of transformer oil are, a) Colour – pale yellow. b) Moisture content -
Description : What is the normal value of moisture content allowed in transformer oil?
Last Answer :
Description : What is gap between the electrodes in transformer oil testing kit?
Last Answer : 0.1 Inch.
Description : Which of the following has the lowest Prandtl number? (A) Molten sodium (a coolant used in fast breeder reactor) (B) Water (C) Transformer oil (D) Dilute H2SO4
Last Answer : (A) Molten sodium (a coolant used in fast breeder reactor)
Description : The total permittivity of a dielectric transformer oil (relative permittivity is 2.2) will be (in order 10 -11 ) a) 1.94 b) 19.4 c) 0.194 d) 194
Last Answer : a) 1.94
Description : Find the electric flux density surrounding a material with field intensity of 2xyz placed in transformer oil ( εr = 2.2) at the point P(1,2,3) is (in 10 -10 units) a) 2.1 b) 2.33 c) 2.5 d) 2.77
Last Answer : c) 2.5
Description : Find the electric field intensity of transformer oil (εr = 2 approx) with density 1/4π (in 10 9 units) a) 2.5 b) 3.5 c) 4.5 d) 5.5
Last Answer : c) 4.5
Description : Find the force of interaction between 60 stat coulomb and 37.5 stat coulomb spaced 7.5cm apart in transformer oil(εr=2.2) in 10 -4 N, a) 8.15 b) 5.18 c) 1.518 d) 1.815
Last Answer : d) 1.815
Description : 76 The changes in volume of transformer cooling oil due to variation of atmospeheric temperature during day and night is taken care of by which part of transformer? A. Conservator B. Breather C. Bushings D. Buchholz relay
Last Answer : A. Conservator
Description : 67 The chemical used in breather for transformer should have the quality of A. Ionizing air B. Absorbing moisture C. Cleansing the transformer oil D. Cooling the transformer oil
Last Answer : B. Absorbing moisture
Description : 63 The dielectric strength of transformer oil is expected to be A. 1kV B. 33kV C. 100kV D. 330 kV
Last Answer : B. 33kv
Description : 45 The function of conservator in a transformer is A. To protect against internal fault B. To reduce copper as well as core losses C. To cool the transformer oil D. To take care of the expansion and contraction of transformer oil due to variation of temperature of surroundings
Last Answer : D. To take care of the expansion and contraction of transformer oil due to variation of temperature of surroundings
Description : 19 Transformer cores are built up from laminations rather than from solid metal so that A. Oil penetrates the core more easily B. Eddy current loss is reduced C. Less lamination is required for the windings D. Turn ratio is higher than voltage ratio
Last Answer : B. Eddy current loss is reduced
Description : The dielectric strength of transformer oil should be (A) 100 V. (B) 5 KV. (C) 30 KV. (D) 132 KV.
Last Answer : (C) 30 KV.
Description : The flash point of transformer oil should be higher than (a) 40°C (b) 60°C (c) 80°C (d) 104°C
Last Answer : (d) 104°C
Description : State the causes for dielectric failure of highly purified transformer oil.
Last Answer : The causes for dielectric failure of highly purified transformer oil: 1. Voltage rating 2. Humidity in atmosphere 3. Temperature of the oil 4. Due to improper cable joints and connection. 5. Increasing in supply frequency. 6. Due to unbalanced load.
Description : Define Dielectric Strength for transformer oil. State its value for new transformer oil.
Last Answer : Dielectric strength is defined as the maximum voltage that can be applied to across to the Fulid with out electrical breakdown is called Dielectric strength.
Description : State and explain properties of transformer oil.
Last Answer : Following are the properties of transformer oil:- 1. Dielectric strength :- It should be have a high dielectric strength 2. Specific resistance:- It should be have a high Specific ... be not contain impurities such as sulpher & its compounds to avoid rusting & sludge formation.
Description : List any eight contamination agents of the transformer oil.
Last Answer : The insulating oil gets contaminated when the following impurities are present in oil. 1. Presence of dissolved moisture content. 2. Presence of water content. 3. Presence of dissolved gases ... sulpher content 9. Presence of acetones content. 10. Presence of dissolved oil decay products content
Description : The function of oil in a transformer is to provide A) Insulation and cooling B) Protection against Lightning C) Protection against short circuit D) Lubrication
Last Answer : The function of oil in a transformer is to provide Insulation and cooling
Description : Transformer oil tester is used to know • Permittivity • Permeability • Dielectric strength • Resistance of the oil
Last Answer : Transformer oil tester is used to know Dielectric strength
Description : In an oil filled transformer, oil is provided for (A) cooling (B) insulation (C) lubrication (D) both (A) and (B)
Last Answer : In an oil filled transformer, oil is provided for (A) cooling (B) insulation (C) lubrication (D) both (A) and (B)
Last Answer : A transformer oil must be free from moisture.
Last Answer : Gas is usually not liberated due to dissociation of transformer oil unless the oil temperature exceeds 150°C.
Description : The dielectric strength of transformer oil is expected to be?
Last Answer : The dielectric strength of transformer oil is expected to be 33 kV.