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 are the types of cooling in transformer?
Last Answer : 1. Natural cooling. a. Air natural cooling (Dry type). b. Oil immersed natural cooling. c. Oil immersed, forced oil circulation with natural cooling. 2. Artificial cooling. a. Oil immersed forced ... This is the method of cooling combining oil natural, water, air natural, air blast and forced oil.
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 : Explain the different types of transformer cooling.
Last Answer : Types of cooling systems in a transformer : Transformer cooling may be classified as natural and forced. Oil natural, air natural Oil natural, air forced Oil forced, air natural Oil forced, air forced OIl forced, water forced
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 : 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 : 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 : What are the types of cooling systems it transformers?
Last Answer : A. 1. ONAN (oil natural, air natural) 2. ONAF (oil natural, air forced) 3. OFAF (oil forced, air forced) 4. ODWF (oil direct, water forced) 5. OFAN (oil forced, air forced)
Description : 38] In a transformer the energy is conveyed from primary to secondary? A. Through cooling coil B. Through air C. By the flux D. None of the above
Last Answer : C. By the flux
Description : Why a transformer requires cooling. What are the methods of cooling transformers?
Last Answer : Ans. Transformers requires cooling as they get heated up due to various losses taking place in the transformer. (like iron of copper losses) Following are the methods of cooling of transformer. a. Natural ... . Forced oil air Natural Cooling (OFAN). d. Forced oil and forced Air cooling (OFAF).
Description : Describe any two methods for transformer cooling.
Last Answer : Methods of Cooling of Transformer: - i) Oil Natural Air natural (O.N.A.N.):- This type of cooling is used for transformer upto rating of 30 MVA. The basic structure of transformer ... a pump. This type of cooling is used for transformers having rating of few MVA (generating transformer)
Last Answer : A common method of cooling a power transformer is oil cooling.
Description : Why we do 2 types of earthing on transformer i.e.: body earthing & neutral earthing, what is function. I am going to install a 5oo kva transformer & 380 kva DG set what should the earthing value?
Last Answer : The two types of earthing are Familiar as Equipment earthing and system earthing. In Equipment earthing: body (non conducting part) of the equipment should be earthed to safeguard the human ... earthing will be further classified into directly earthed, Impedance earthing, resistive (NGRs) earthing.
Description : How Many Types Of Colling System It transformer ?
Last Answer : ONAN (oil natural, air natural). ONAF (oil natural, air forced). OFAF (oil forced, air forced). ODWF (oil direct, water forced). OFAN (oil forced,air forced).
Description : What are the various types of three phase transformer connections?
Last Answer : The most common types of transformer connections are, i. Star-Star (Y-Y) ii. Delta-Delta(∆-∆) iii. Star-Delta (Y-∆) iv. Delta-Star (∆-Y) v. Open Delta (V-V) vi. Scott Connection (T-T)
Description : What are the different types of faults in a transformer?
Last Answer : The internal faults include phase faults, ground faults, inter-turn faults, tap-changer failure, and leakage oil from tank. The external faults include system phase faults, system ground faults, over loads and over fluxing.
Description : What are the types of bushing used in transformer?
Last Answer : Condenser type bushing Porcelain type bushing
Description : What are the types of transformer core?
Last Answer : a. Core type transformer core. b. Shell type transformer core. c. Berry type transformer core. d. Spiral type transformer core.
Description : In accordance with Coast Guard Regulations (46 CFR), a circuit breaker located in the machinery space and installed in a 440V AC system must _____________. A. be dependent upon mechanical ... the maximum asymmetrical shortcircuit current available at the point of application D. all of the above
Description : If overloading a DC machine becomes necessary in an emergency, you should ____________. A. cool the machine with portable blowers and fans B. hold thermal overload relays open with blocks of ... the windings for cooling D. increase the residual magnetism value of windings to reduce eddy currents
Description : Two contributors of electronic console failures are heat and vibration. To combat some of their effects, preventive maintenance procedures should include ______________. A. systematic rotation of circuit cards with those ... bolts and changing of the air in the control room D. all of the above
Last Answer : Answer: B
Description : What type of cooling is provided for Generator in power plant?
Last Answer : Hydrogen gas cooling is employed for large size generators because of better heat carrying ability of the hydrogen. Hydrogen cooling is provided for rotors and core of the generator. Water cooling is provided for the stator of the alternator.
Description : Why cooling towers require in the Steam power plant ?
Last Answer : Cooling towers cool the warm water discharged from the condenser and feed the cooled water back to the condenser. There are two types of cooling methods provided in the cooling towers, they can be either ... finned tubes over which cooling air is passed. Heat is rejected to air as water is cooled
Description : Discuss how the ventilation and cooling of large high speed alternator is carried out.
Last Answer : For high speed alternator two cooling methods are available and they are conventional cooling and direct cooling. In conventional cooling methods, radial and axial ventilating ducts are provided in the ... oil or hydrogen are circulated in the ducts to remove the heat directly from the conductors.
Description : How the heat dissipation is improved by providing the cooling tubes?
Last Answer : The cooling tubes will improve the circulation of oil. The circulation of oil is due to effective pressure heads produced by columns of oil in tubes. The improvement in cooling is accounted by taking the specific heat dissipation due to convection as 35% more than that without tubes.
Description : Why cooling tubes are provided?
Last Answer : Cooling tubes are provided to increase the heat dissipating area of the tank.
Description : What are the factors to be considered for choosing the method of cooling?
Last Answer : The choice of cooling method depends on KVA rating of transformer, size, application and the site conditions where it will be installed.
Description : List some methods of cooling of transformers.
Last Answer : A:Air natural, Air blast, Oil Natural, Oil natural air forced, Oil natural water forced, Oil forced, Oil forced air natural, Oil forced air natural, Oil forced water forced.
Description : What is the working principle of Cooling Towers?
Last Answer : The hot water is sprayed from the top of the tower, while the air is made to flow from the bottom of the tower to the top. This air cools the hot water in the cooling tower. Air vaporises ... and leaves at the top of the tower and cooled water leaves at the bottom and recirculated to the condenser.
Description : What is meant by cooling Towers?
Last Answer : It is a tower or building like device in which atmospheric air circulates in direct or indirect contact with warmer water and water is thereby cooled. Cooling towers may either use the evaporation of water to remove process heat and cool the working fluid
Description : What consists of cooling water circuit and coal & ash circuit in steam power plant?
Last Answer : The cooling water circuit consists of a pump, condenser and cooling tower. The coal and ash circuit consists of coal delivery, preparation of coal, handling of coal to the boiler furnace, ash handling and ash storage.
Description : How selection of cooling fluid in GT done?
Last Answer : a) There are 5 factors are there. b) Density c) Coefficient of thermal expansion d) Viscosity e) Specific heat f) Thermal conductivity.
Description : How cooling is done for slip ring and brush gear?
Last Answer : A centrifuge fan is mounted on the shaft in between two slip rings for ventilation of the slip rings and brush gear.
Description : In MAPS Unit # 1 end-shield cooling system has got heaters. Why?
Last Answer : Unit # 1 end-shield is made of nickel steel, which had a nil ductility temperature of -100°C while commissioning. After 30 years of operation this will rise to +32°C, because of radiation exposure. ... #2 this problem is not existed because in this unit end-shields are made up of stainless steel.
Description : During loca how the cooling of fuel bundle is achieved?
Last Answer : During loca there is provision for taking D2O from the moderator system, which is connected to PHT system for fuel cooling and there is one more option for the cooling of the fuel from the fire water system.
Description : What is the cooling water used in moderator heat exchanger during normal operation? And during class IV failure?
Last Answer : During normal operation process LP water is used in moderator heat exchangers, which transfers heat to seawater. During class IV failure firewater is used for the moderator heat exchanger.
Description : What you mean by cooling method?
Last Answer : Cooling method means elimination of heat from the fire.
Description : What is the cooling medium for different parts of the turbo generator?
Last Answer : Stator – DM water. Rotor – Hydrogen. Bearing – Oil.
Description : Three solid objects of the same material and of equal mass-a sphere, a cylinder (length = diameter) and a cube are at 500°C initially. These are dropped in a quenching bath containing a large volume of cooling oil ... (A) Cube (B) Cylinder (C) Sphere (D) Equal for all the three
Last Answer : (A) Cube
Description : Common applications of Cooling towers include a. Cooling the circulating water used in oil refineries b. petrochemical and other chemical plants c. thermal power stations d. All of the above.
Last Answer : All of the above.