Natural oil cooling is used for transformers up to a rating of?

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).

6 views 1 answer

asked Jun 20, 2021 by itszee

What will happen if the transformers working in parallel are not connected with regard to polarity ?

Last Answer : Winding will be damaged

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asked Mar 19, 2018 by anonymous

If the percentage impedances of the two transformers working in parallel are different, then?

If the percentage impedances of the two transformers working in parallel are different, then?
Last Answer : If the percentage impedances of the two transformers working in parallel are different, then parallel operation will still be possible, but the power factors at which the two transformers operate will be different from the power factor of the common load.

131 views 1 answer

asked Mar 19, 2018 by anonymous

Distribution transformers are generally designed for maximum efficiency around?

Last Answer : Distribution transformers are generally designed for maximum efficiency around 50% load.

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asked Mar 19, 2018 by anonymous

Power transformers are generally designed to have maximum efficiency around?

Last Answer : Power transformers are generally designed to have maximum efficiency around near full-load.

107 views 1 answer

asked Mar 19, 2018 by anonymous

Two transformers do not have equal percentage impedance. This is likely to result in?

Two transformers are connected in parallel. These transformers do not have equal percentage impedance. This is likely to result in?
Last Answer : Two transformers are connected in parallel. These transformers do not have equal percentage impedance. This is likely to result in loading of the transformers not in proportion to their kVA ratings.

377 views 1 answer

asked Mar 19, 2018 by anonymous

Short circuit test on transformers is conducted to determine?

Last Answer : Short circuit test on transformers is conducted to determine copper losses.

218 views 1 answer

asked Mar 19, 2018 by anonymous

For the parallel operation of single phase transformers it is necessary that they should have?

Last Answer : Necessary conditions required to be satisfied in order to ensure successful parallel operation of single phase transformers: 1. Only transformers having the same phase displacement between primary and secondary ... . 7. The phase sequence must be followed strictly on HV and LV side connection.

197 views 2 answers

asked Mar 19, 2018 by anonymous

Losses which occur in rotating electric machines and do not occur in transformers are?

Losses which occur in rotating electric machines and do not occur in transformers are?
Last Answer : Friction losses windage losses

208 views 2 answers

asked Mar 19, 2018 by anonymous

The efficiency of two identical transformers under load conditions can be determined by?

The efficiency of two identical transformers under load conditions can be determined by?
Last Answer : The efficiency of two identical transformers under load conditions can be determined by back-to-back test.

323 views 1 answer

asked Mar 19, 2018 by anonymous

The efficiencies of transformers compared with that of electric motors of the same power are?

The efficiencies of transformers compared with that of electric motors of the same power are?
Last Answer : Transformers have high efficiency than the same ratted motors

179 views 2 answers

asked Mar 19, 2018 by anonymous

Cooling Fans

Cooling Fans
Last Answer : Many notebook computer users think that the term "laptop" is a misnomer. After a few hours of use, a notebook computer can get a bit too hot, which makes it uncomfortable to operate on your lap. ... fan will not only keep your notebook in tip-top shape, but it will also make cooler heads prevail.

7 views 1 answer

asked May 5, 2021 by anonymous

Draw and explain the function of cooling tower in TPS.

Draw and explain the function of cooling tower in TPS.
Last Answer : Cooling tower in TPS: The function of cooling tower is to reduce the temperature of water coming from condenser. Water is circulated from the basin of the cooling ... cooling Tower temperature of water is reduced either by natural or forced or induced draught method or combine

108 views 1 answer

asked Aug 2, 2019 by anonymous

State the function of cooling tower and condenser in thermal power station.

State the function of cooling tower and condenser in thermal power station.
Last Answer : 1. Condenser: Function of condenser is to convert exhaust steam again into water by reducing its temperature with the help of cold water. Also it reduces back pressure of steam turbine 2 ... tower : The function of cooling tower is to reduce the temperature of water coming from condenser.

315 views 1 answer

asked Sep 8, 2018 by anonymous

Which of the following is used for thermoelectric cooling?

Which of the following is used for thermoelectric cooling? A) Peltier effect B) Seebeck effect C) Both A and B D) None of these
Last Answer : Which of the following is used for thermoelectric cooling? A) Peltier effect B) Seebeck effect C) Both A and B D) None of these

98 views 1 answer

asked Apr 29, 2018 by anonymous

Harmonics in transformer result in?

Last Answer : Harmonics in transformer result in increased core losses, increased I2R losses, and magnetic interference with communication circuits.

70 views 1 answer

asked Mar 19, 2018 by anonymous

74)Power transformers are generally designed to have maximum efficiency around A. No load B. Half load C. Near full load D. 10% overload

74)Power transformers are generally designed to have maximum efficiency around A. No load B. Half load C. Near full load D. 10% overload
Last Answer : C. Near full load

14 views 1 answer

asked Jul 21, 2021 by jyoti kurekar

[23] Transformers are rated in KVA instead of KW because A. load power factor is often not known B. KVA is fixed whereas KW depends on load power factor C. Total transformer loss depends on volt ampere D. It has become customary

[23] Transformers are rated in KVA instead of KW because A. load power factor is often not known B. KVA is fixed whereas KW depends on load power factor C. Total transformer loss depends on volt ampere D. It has become customary
Last Answer : C. Total transformer loss depends on volt ampere

130 views 1 answer

asked Jul 21, 2021 by jyoti kurekar

TRANSFORMERS MCQ

TRANSFORMERS MCQ
Last Answer : 101. A shell-type transformer has (a) high eddy current losses (b) reduced magnetic leakage (c) negligibly hysteresis losses (d) none of the above Ans: b 102. A transformer can have regulation closer to zero (a ... (6) much smaller (c) much higher (d) somewhat smaller (e) none of the above Ans: c

539 views 3 answers

asked Jun 22, 2021 by itszee

What are the schedules of maintenance done on transformers?

What are the schedules of maintenance done on transformers?
Last Answer : Ans. Following are the schedules of maintenance on transformers. a. Daily maintenance. b. Monthly maintenance. c. Quarterly maintenance. d. Half yearly maintenance. e. Yearly maintenance. f. 5 Yearly maintenance.

7 views 1 answer

asked Jun 20, 2021 by itszee

What are the loses in Transformers, Explain?

What are the loses in Transformers, Explain?
Last Answer : Ans. (1) Iron loses (2) Copper loses Iron Loss : Iron loss occurs in the transformers Iron core due to hysteresis and eddy currents taking place. They are almost fixed irrespective of ... losses in the primary and the secondary windings of the transformer which with the loading of transformer.

3 views 1 answer

asked Jun 20, 2021 by itszee

the volt per turn of a certain single phase transformers is 1.7. the transformer has a step ratio of 3825/255volt. calculate the respective number of turns in each winding

63 views 0 answers

asked Aug 13, 2019 by Alacrity

Classify the transformers based on the construction, frequency and power.

Classify the transformers based on the construction, frequency and power.
Last Answer : Classification of Transformer Based On: i) Construction: Shell type, Core type, Berry type ii) Change in voltage level: Step-Up, Step-Down, iii) Number of phases: Single phase, Three phase iv) ... Control vi) Cooling: Self-cooled, Air-cooled, Forced-air cooled, Oil-cooled, Forced-oil cooled.

133 views 1 answer

asked Aug 30, 2018 by anonymous

Which of the following connection of transformers will give highest value of secondary voltage ?

Which of the following connection of transformers will give highest value of secondary voltage ? (A) Delta primary delta secondary (B) Delta primary star secondary (C) Star primary star secondary (D) Star primary delta secondary
Last Answer : Which of the following connection of transformers will give highest value of secondary voltage ? (A) Delta primary delta secondary (B) Delta primary star secondary (C) Star primary star secondary (D) Star primary delta secondary

580 views 1 answer

asked May 8, 2018 by anonymous

Two transformers A and B having equal outputs and voltage ratios but unequal percentage

Two transformers A and B having equal outputs and voltage ratios but unequal percentage impedances of 4 and 2 are operating in parallel. The transformer A will be overloaded by
Last Answer : Two transformers A and B having equal outputs and voltage ratios but unequal percentage impedances of 4 and 2 are operating in parallel. The transformer A will be overloaded by 33%

672 views 1 answer

asked May 8, 2018 by anonymous

Core type transformers are popular in___________.

Core type transformers are popular in___________. (A) High voltage applications (B) Low voltage applications (C) All of the above (D) None of the above
Last Answer : Core type transformers are popular in High voltage applications

96 views 1 answer

asked May 8, 2018 by anonymous

In a transmission line if booster transformers are to be used, preferred location will be

In a transmission line if booster transformers are to be used, preferred location will be (A) At the receiving end (B) At the sending end (C) At the intermediate point (D) Anywhere in the line
Last Answer : In a transmission line if booster transformers are to be used, preferred location will be At the intermediate point

346 views 1 answer

asked May 8, 2018 by anonymous

The friction losses in Real Transformers are :

The friction losses in Real Transformers are : (A) 0% (B) 5% (C) 25% (D) 50%
Last Answer : A

3.3k views 2 answers

asked May 8, 2018 by anonymous

Two 3-phase transformers cannot be operated in parallel, if their :

Two 3-phase transformers cannot be operated in parallel, if their : (A) kVAs are different (B) phase sequences are different (C) % impedances are different (D) voltage ratios are different
Last Answer : Two 3-phase transformers cannot be operated in parallel, if their : phase sequences are different

151 views 1 answer

asked Apr 30, 2018 by anonymous

An additional condition for parallel operation of three-phase transformers over single-phase transformers is that

An additional condition for parallel operation of three-phase transformers over single-phase transformers is that
Last Answer : An additional condition for parallel operation of three-phase transformers over single-phase transformers is that the transformers should belong to the same vector group

144 views 1 answer

asked Apr 29, 2018 by anonymous

Which of the following is the advantage of using CRGO steel in transformers?

Which of the following is the advantage of using CRGO steel in transformers? A) High magnetic flux density B) Low permeability C) Both A and B D) None of these
Last Answer : It definitely High Magnetic Flux Density since a crgo steel has always a more around 3% of silicon proportion among the remaining ferrite which make cold rolled grain oriented steel having high flux magnetic ... for more about the crgo core you can learn here https://nicoreindia.com/crgo-core/

153 views 2 answers

asked Apr 29, 2018 by anonymous

Instrument transformers are?

Last Answer : Instrument transformers are potential transformers, current transformers.

84 views 1 answer

asked Mar 21, 2018 by anonymous

What is the back EMF in Transformers?

77 views 0 answers

asked Mar 15, 2018 by anonymous

of what use are current and voltage transformers in protective systems

Last Answer : Current transformers (CT) : Current transformer (CT) actually step down the high current to low current for the operation of relays. Current transformer is use for measurement of ... use for relay. This is about potential transformer.

137 views 1 answer

asked Jan 15, 2018 by James

Why do transformers make noise?

Why do transformers make noise?
Last Answer : Transformers make noise based on it out put if an transformer outputs is 400v maximum than a 398v be apply to that transformer it also make a noise because of that

91 views 1 answer

asked Dec 17, 2017 by anonymous

What is largest rating transformer

2.5k views 0 answers

asked Jul 24, 2019 by Deepak kumar bharti

Why circuit breaker connect b)w two transformer (same rating

Why circuit breaker connect b)w two transformer (same rating
Last Answer : Because two transformers connection is in parallel to share the load if any transformer is receives the surge current because of the fault so to protect the other transformer from the fault.

113 views 1 answer

asked Apr 28, 2019 by Umar Yousaf

What happens when you converts two isotopic versions of a metal into a plasma and then cool them down?

What happens when you converts two isotopic versions of a metal into a plasma and then cool them down?
Last Answer : Let me ask you a question. If you add hydrogen gas to a room, where does it collect? It depends on the metal and method. I’ve heard of using induction of a plasma state along with a centrifugal system, but isotopes and inorganic chem isn’t really my thing.

2 views 1 answer

asked Mar 2 by anonymous

78 Which type of winding is used in 3 phase shell type transformer? A. Circular type B. Sandwich type C. Cylindrical type D. Rectangular type

78 Which type of winding is used in 3 phase shell type transformer? A. Circular type B. Sandwich type C. Cylindrical type D. Rectangular type
Last Answer : B. Sandwich type

35 views 1 answer

asked Jul 21, 2021 by jyoti kurekar

73 The full load copper loss of a transformer is 1600W. At half-load the copper loss will be A. 6400W B. 1600W C. 800W D. 400W

73 The full load copper loss of a transformer is 1600W. At half-load the copper loss will be A. 6400W B. 1600W C. 800W D. 400W
Last Answer : D. 400W

13 views 1 answer

asked Jul 21, 2021 by jyoti kurekar

5 The efficiency of a transformer is maximum when A. It runs at half full load B. it runs at full load C. its Cu loss equal iron loss D. it runs over load

5 The efficiency of a transformer is maximum when A. It runs at half full load B. it runs at full load C. its Cu loss equal iron loss D. it runs over load
Last Answer : C. Its cu loss equal iron loss

18 views 1 answer

asked Jul 21, 2021 by jyoti kurekar

State any two applications of single phase autotransformer.

State any two applications of single phase autotransformer.
Last Answer : Applications of single phase auto transformers: 1) Give small boost to distribution cable to correct the voltage drop. 2) As auto transformer starter for induction motors. 3) As furnace supply ... . 5) In control equipment for single phase locomotives. 6) As dimmer in lighting circuits.

52 views 1 answer

asked Jan 8, 2021 by anonymous

State any two conditions for parallel operation of 3-phase transformer.

State any two conditions for parallel operation of 3-phase transformer.
Last Answer : Conditions for Parallel operation of 3 phase transformer 1) Voltage ratings of both the transformers must be identical. 2) Percentage or p.u. impedance should be equal in magnitude. 3) X/R ratio ... between primary & secondary voltages must be same. 6) Phase sequence on both sides must be same.

50 views 1 answer

asked Jan 8, 2021 by anonymous

Compare core type transformer and shell type transformer on the following parameters. (i) Types of winding used, (ii) Application

Compare core type transformer and shell type transformer on the following parameters. (i) Types of winding used, (ii) Application
Last Answer : Ans:

52 views 1 answer

asked Jan 8, 2021 by anonymous

Define transformation ratio in terms of current and voltage.

Define transformation ratio in terms of current and voltage.
Last Answer : (i) Transformation Ratio (K) is defined as the ratio of the primary current to the secondary current. (ii) Transformation Ratio (K) is defined as the ratio of the secondary voltage to the primary voltage.

41 views 1 answer

asked Jan 8, 2021 by anonymous

Define: (i) Commercial efficiency of a transformer and (ii) All day efficiency of a transformer.

Define: (i) Commercial efficiency of a transformer and (ii) All day efficiency of a transformer.
Last Answer : (i) Commercial Efficiency : It is the ratio of output power in watt to the input power in watt. (ii) All day efficiency of a transformer: It is the ratio of output energy in kWh to the input energy in kWh in the 24 hours of the day

135 views 1 answer

asked Jan 8, 2021 by anonymous

A 50 KVA transformer has iron loss 2 kW on full load. Calculate its iron loss at 75% of full load.

A 50 KVA transformer has iron loss 2 kW on full load. Calculate its iron loss at 75% of full load.
Last Answer : Iron loss is dependent on voltage and independent of load. Hence iron loss at 75% of Load = Iron loss at full load = 2 kW

104 views 1 answer

asked Jan 8, 2021 by anonymous

State any four properties of Ideal transformer.

State any four properties of Ideal transformer.
Last Answer : Properties of Ideal transformer: 1) No losses (iron and copper losses), hence no temperature rise. 2) No magnetic leakage i.e (Coefficient of coupling between primary and secondary windings is unity) 3) Zero winding ... drop i.e. E1 = V1, E2 = V2 5) Efficiency 100 %. 6) Regulation 0 %.

34 views 1 answer

asked Jan 8, 2021 by anonymous

anonymous · Answer 1 · 2018-03-19T21:44:32+0000

Natural oil cooling is used for transformers up to a rating of 3000 kVA.

Natural oil cooling is used for transformers up to a rating of?

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