Description : What is Meant by Temperature Rise in a Transformer?
Last Answer : ANSWER: Temperature rise in a transformer is the temper¬ature of the windings and insulation above the existing ambi¬ent or surrounding temperature, and is determined by the insulation class used in the transformer coils.
Last Answer : yes High Voltage side of Transformer winding have more number of turns. and low voltage side of Transformer winding have less number of turns.
Description : 51 A transformer has negative voltage regulation when its load power factor is A. Zero B. Unity C. Leading D. Lagging
Last Answer : C. leading
Description : State and justify which of the following two transformers is better: Transformer A = 4% voltage regulation Transformer B = 6% voltage regulation
Last Answer : Transformer A with 4% voltage regulation is better. Justification: Voltage regulation refers to the percentage change in secondary voltage when load is changed from no-load to full-load with primary voltage ... 4% voltage regulation, which is less as compared to 6% of transformer B, it is better.
Description : A transformer has negative voltage regulation when its load power factor is (1) Zero (2) Unity (3) Leading (4) Lagging
Last Answer : 0
Description : A good voltage regulation of a transformer means?
Last Answer : A good voltage regulation of a transformer means output voltage fluctuation from no load to full load is least.
Description : What is tertiary winding? What is Three Winding Transformer? What are its advantages?
Last Answer : A. In some high rating transformers, one winding, in addition to the primary and secondary winding, is used. This is known as Tertiary Winding of Transformer. Because of this third winding, the ... it assists in limitation of fault current in the event of a short circuit from line to neutral.
Description : What is Six winding transformer?
Last Answer : Three windings in primary and three windings in secondary are used, They are three phase transformers.They are connected in either star-star, delta-delta, star delta or delta star.
Description : What is Three winding transformer?
Last Answer : Three windings are used each work as primary and secondary. Also primary and secondary windings are conductively couple. They are three phase auto transformer
Description : What is Two winding transformer?
Last Answer : Two separate windings one as primary and other as secondary are used. Both windings are magnetically coupled.
Description : What is Meant by Regulation in a Transformer?
Last Answer : ANSWER: Voltage regulation in transformers is the difference between the no load voltage and the full load voltage. This is usually expressed in terms of percentage. For example: A transformer delivers 100 ... from 2% to 4%, depending on the size and the application for which they are used
Description : What is meant by regulation in a transformer?
Last Answer : A. Voltage regulation in transformers is the difference between the no load voltage and the full load voltage. This is usually expressed in terms of percentage. Example: A Transformer delivers 100 ... The regulation capacity varies depending on the size and the application for which they are used.
Last Answer : Voltage regulation in transformers is the difference between the no load voltage and the full load voltage. This is usually expressed in terms of percentage. For example: A transformer delivers 100 volts ... voltage drop in transformer/ no load voltage of transformer V2>E2 for leading p.f load V2
Description : Explain about the open and short circuit tests on transformer?
Last Answer : A. Open circuit test (No load test) and short circuit test (full load test) are performed on a transformer to determine (i) Equivalent circuit of transformer (ii) Voltage ... determine copper loss in transformer at full load and parameters of approximate equivalent circuit of transformer.
Description : In transformers, why the low voltage winding is placed near the core?
Last Answer : The winding & Core are both made of metals and so an insulation have to be placed in between them, the thickness of insulation depends on the voltage rating of the winding. In order to reduce the insulation requirement the low voltage winding place near the core.
Description : What are the factors affecting voltage regulation?
Last Answer : Load current Equivalent resistance Equivalent reactance power factor
Description : What is the condition for maximum voltage regulation?
Last Answer : It occurs when load is inductive and power factor is lagging.
Description : What is the condition for zero voltage regulation?
Last Answer : Negative sign indicates zero voltage regulation. It occurs when load is capacitive and power factor is leading.
Description : 6 In a two winding transformer, the primary and secondary induced emf E1 & E2 are always A. equal in magnitude B. anti phase with each other C. in phase with each other D. determined by load on transformer secondary
Last Answer : C. In phase with each other
Description : A two-winding single phase transformer has a voltage regulation of 4.5% at full-load and unity power-factor. At full-load and 0.80 power-factor lagging load the voltage regulation will be (A) 4.5%. (B) less than 4.5%. (C) more than 4.5%. (D) 4.5% or more than 4.5%.
Last Answer : (C) more than 4.5%.
Description : At what power maximum efficiency of power transformer and distribution transformer is designed
Last Answer : Maximum efficiency of the transformer is attained at certain load factor (α) when core losses of transformer is equal to the copper losses. PCore loss = α ^2 X PCopper loss From the ... the day. Hence distribution transformers are designed to have maximum efficiency at 50% of the rated full load
Description : Define all day efficiency of a transformer?
Last Answer : A:It is computed on the basis of energy consumed during a certain period, usually a day of 24 hrs. All day efficiency=output in kWh/input in kWh for 24 hrs.
Description : What is the condition for maximum efficiency of transformer?
Last Answer : When Iron losses is equal to copper losses.
Description : Define efficiency of the transformer?
Last Answer : Transformer efficiency ƞ= (output power/input power) x 100
Description : Why the efficiency of distribution transformer is 60 to 70 % and not 100%?
Last Answer : Distribution transformer is designed for maximum efficiency at 60% to 70% load as it normally doesn't operate at full load all the time. Its load depends on distribution demand. Whereas power transformer ... efficiency at 100% load as it always runs at 100% load being near to generating station.
Description : A megger is being used to test the insulation of an AC generator. The resistance value of a dry, clean winding will _____________. A. continue to rise as test potential is maintained, ... , becoming fairly steady after 5-7 minutes D. stabilize after approximately 2-4 minutes of fluctuation
Last Answer : Answer: A
Description : You are testing the insulation in an AC generator with a megohmeter. The resistance value of a dry, clean winding will ____________. A. continue to rise as the test potential is maintained, ... fairly steady after 5 to 7 minutes D. stabilize after approximately 2 to 4 minutes of fluctuation
Description : What is temperature rise in a transformer?
Last Answer : Temperature rise in a transformer is the temperature of the windings and insulation above the existing ambient or surrounding temperature.
Description : If a transformer is continuously operated the maximum temperature rise will occur in?
Last Answer : If a transformer is continuously operated the maximum temperature rise will occur in windings.
Description : 28.In a two winding transformer, the emf /turn in secondary winding is always......the induced emf power turn in primary A. equal to k times B. equal to 1/k times C. equal D. greater than
Last Answer : C. equal
Description : 27] In a transformer, the leakage flux of each winding is proportional to the current in that winding because A. Ohm's law applies to magnetic circuits B. Leakage paths do no saturate C. the two windings are electrically isolated D. mutual flux is confined to the core
Last Answer : B. Leakage path do not saturate
Description : 12] Which is not the basic element of the transformer? A. core B. primary winding C. secondary winding D. mutual flux
Last Answer : D. Mutual flux
Description : 7 The main advantage of auto transformer over a two winding transformer is A. Hysteresis losses are reduced B. Saving in winding material C. Copper losses are negligible D. Eddy losses are totally eliminated
Last Answer : A) hysteresis losses is reduced
Description : A certain transformer has 200 turns in the primary winding, 50 turns in the secondary winding and 120 volts applied to the primary. What is the voltage across the secondary? (A) 30 Volts (B) 480 Volts (C) 120 Volts (D) 60 Volts
Last Answer : A certain transformer has 200 turns in the primary winding, 50 turns in the secondary winding and 120 volts applied to the primary. What is the voltage across the secondary? (A) 30 Volts (B) 480 Volts (C) 120 Volts (D) 60 Volts
Last Answer : The short circuit in any winding of the transformer is the result of impulse voltage.
Last Answer : In the transformer low voltage winding has got more cross-sectional area.
Last Answer : Primary winding of a transformer could either be a low voltage or high voltage winding.
Last Answer : High voltage winding in a transformer has more number of turns.
Last Answer : High voltage winding of the transformer has less cross-sectional area.
Last Answer : Sandwich type winding is used in 3 phase shell-type transformer.
Last Answer : A transformer can have regulation closer to zero on leading power factor.
Description : A ferro resonant transformer regulation is also known as?
Last Answer : A ferro resonant transformer regulation is also known as constant current transformer.
Description : Define the percentage voltage regulation and efficiency of a power transformer.
Last Answer : Voltage regulation is the difference between no load voltage and full load voltage by no load voltage. Voltage regulation = No load voltage - Full load voltage / No load voltage. Voltage regulation is mentioned ... . % Efficiency = Output in watts * 100 / Output in watts + losses.
Description : What is voltage ratio of a transformer?
Last Answer : A. Voltage ratio is the ratio of the voltage between the line terminals of one winding to that between the line terminals of another winding at no load.
Description : If we give 2334 A, 540V on Primary side of 1.125 MVA step up transformer, then what will be the Secondary Current, If Secondary Voltage=11 KV?
Last Answer : A. As we know the Voltage & current relation for transformer-V1/V2 = I2/I1 We Know, VI= 540 V; V2=11KV or 11000 V; I1= 2334 Amps. By putting these value on Relation540/11000= I2/2334 So,I2 = 114.5 Amps
Description : What will happen if transformer in parallel connection have different voltage ratio?
Last Answer : Two transformers in Parallel should have the same primary and secondary voltage ratings. Any error in the voltage ratio would cause heavy circulating currents to flow between the transformers. ... in overloading of one transformer. This circulating current will result in increased copper losses.
Description : Why the open circuit test on a transformer is conducted at rated voltage?
Last Answer : A:The open circuit on a transformer is conducted at a rated voltage because core loss depends upon the voltage. This open circuit test gives only core loss or iron loss of the transformer.
Description : 49 The open circuit test is carried out in a transformer to find the A. Cu loss B. Core loss C. Total loss D. Insulation resistance
Last Answer : B. Core loss
Description : 10] The main reason for generation of harmonics in a transformer could be A. Fluctuating load B. Poor insulation C. Mechanical vibrations D. Saturation of core
Last Answer : D) saturation of core
Description : What is tertiary winding?
Last Answer : Some three phase transformers may have a third winding called tertiary winding apart from primary and secondary. It is also called auxiliary winding or stabilizing winding. The tertiary winding is ... ) to limit short circuit current. iv) to indicate voltage in high voltage testing transformer