1 Answer

Answer :

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

Related questions

Description : Sumpner's test is conducted on transformer to determine?

Last Answer : Sumpner's test is conducted on transformer to determine temprature.

Description : An open-circuit test on a transformer is conducted primarily to measure?

Last Answer : The open-circuit test in a transformer is used to measure

Last Answer : In short circuit test of transformer the low voltage side is short circuited . On high voltage side the voltmeter is connected in parallel and ammeter in series and also a wattmeter is ... circuit test is done for determining impedance and losses. In this test iron losses is neglected.

Description : A no-load test is performed on a transformer to determine?

Last Answer : A no-load test is performed on a transformer to determine magnetizing current and loss.

Last Answer : Hopkinson's test on D.C. machines is conducted at full-load.

Description : Slip test is performed to determine :  (A) Slip in an induction motor  (B) Xd and Xq in a salient pole alternator  (C) Synchronous impedance in an alternator  (D) Positive and negative sequence impedances of an alternator

Last Answer : Slip test is performed to determine :  Xd and Xq in a salient pole alternator 

Description : A parallel RLC circuit has the node equation Determine v(t) using the phasor method.

Last Answer : A parallel RLC circuit has the node equation Determine v(t) using the phasor method.

Description : During open circuit test of a transformer?

Last Answer : During open circuit test of a transformer primary is supplied rated voltage.

Description : Describe the difference between an open circuit and a short circuit.

Last Answer : Open circuit means the wire is cut meaning power will not flow and close circuit means wire is not cut and hence power will flow.Short circuit is the same as close circuit

Description : If the % reactance upto the fault point is 20%, then the short circuit current will be

Last Answer : If the % reactance upto the fault point is 20%, then the short circuit current will be 5 times the full load current

Description : The armature current on symmetrical 3 phase short circuit of a synchronous machine (salient pole)  (A) has q -axis current only (B) has d -axis current only (C) has both d and q axis currents (D) cannot be divided between q and d axis currents

Last Answer : The armature current on symmetrical 3 phase short circuit of a synchronous machine (salient pole) has d -axis current only

Description : Which of the following are known as the short circuit parameters of a 2- port network? (A) Z- parameters. (B) H- parameters. (C) Y- parameters. (D) A,B,C,D, parameters.

Last Answer : Which of the following are known as the short circuit parameters of a 2- port network? (A) Z- parameters. (B) H- parameters. (C) Y- parameters. (D) A,B,C,D, parameters.

Last Answer : The short circuit in any winding of the transformer is the result of impulse voltage.

Description : In which fault the maximum short circuit current occurs?

Last Answer : In three phase bolted fault the maximum short circuit occurs.

Last Answer : Primary side is low voltage side and secondary side is high voltage side.

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

Description : 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.

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

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

Description : 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.

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.

Last Answer : Natural air cooling is generally restricted for transformers up to 1.5 MVA .

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

Last Answer : Friction losses windage losses 

Description : 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.

Description : 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

Description : Using phasors, determine in the following equations

Last Answer : Using phasors, determine in the following equations

Last Answer : A common method of cooling a power transformer is oil cooling.

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

Description : 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

Description : [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

Description : 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

Description : 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.

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 : 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.

Description : 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. 

Description : 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

Description : 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%

Description : 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

Description : 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

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

Last Answer : A

Description : 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

Description : 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

Description : 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/

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

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.

Description : 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