Please Log in or Register for more.


137 views

1 Answer

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 alternating current (AC).
  • When current is very high then we use current transformer.
  • Current transformer is use for monitoring current .
  • When we use current transformer with potential (voltage) transformer then it is known as instrumentation transformer.
  • Current transformer (CT) is also useful for isolating instruments from high voltage.

This is about current transformer (CT).


Potential (voltage) transformer :

  • Potential transformer is also known as voltage transformer.
  • The principle of potential transformer is similar to current transformer.
  • Potential transformer is the step down transformer which step down voltage.
  • Potential transformer may also use for monitoring voltage.
  • The low voltage output of potential transformer can be use for relay.

This is about potential transformer.
Like 0 like

Their use in protective system?? Not general use
Yeah, for lowering of voltage and current for operation of relay. Relay are use for protective system.

Please log in or register to answer this question.

Related Questions


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

Show More

581 views 1 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 
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%

Show More

672 views 1 answer













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

Show More

96 views 1 answer







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

Show More

3.3k views 2 answers







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

Show More

151 views 1 answer







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/

Show More

153 views 2 answers







What is the back EMF in Transformers?

Show More

77 views 0 answers







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

Show More

14 views 1 answer







[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

Show More

130 views 1 answer







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

Show More

541 views 3 answers







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.

Show More

7 views 1 answer







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).

Show More

6 views 1 answer







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.

Show More

3 views 1 answer







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. 

Show More

133 views 1 answer







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

Show More

346 views 1 answer







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

Show More

144 views 1 answer








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

Show More

84 views 1 answer








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

Show More

158 views 1 answer







135 views 2 answers







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.

Show More

131 views 1 answer








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

Show More

142 views 1 answer








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

Show More

107 views 1 answer







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.

Show More

377 views 1 answer








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

Show More

218 views 1 answer








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.

Show More

197 views 2 answers








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

Show More

188 views 1 answer







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

Show More

208 views 2 answers







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.

Show More

323 views 1 answer







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

Show More

179 views 2 answers







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 

Show More

91 views 1 answer







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.

Show More

41 views 1 answer







2.5k views 0 answers







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. 

Show More

113 views 1 answer







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

Show More

35 views 1 answer







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

Show More

13 views 1 answer







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

Show More

18 views 1 answer







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.

Show More

52 views 1 answer







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.

Show More

50 views 1 answer







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

Show More

52 views 1 answer







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

Show More

135 views 1 answer







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

Show More

104 views 1 answer







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 %.

Show More

34 views 1 answer







Draw the connection diagram of long shunt differential D.C. compound generator.
Last Answer : Ans:

Show More

21 views 1 answer








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

Show More

156 views 1 answer








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

Show More

70 views 1 answer







Routine maintenance of dry-type transformers should include ______________. A. preventing the entrance of water from broken pipe lines steam lines B. keeping protective surfaces and insulating bushings free of ... debris C. periodic testing of insulation resistance with a megger D. all of the above
Last Answer : Answer: D

Show More

0 views 1 answer







Circuit breakers are essentially (a) current carrying contacts called electrodes (b) arc extinguishers (c) circuits to break the system (d) transformers to isolate the two systems (e) any of the above
Last Answer : (a) current carrying contacts called electrodes

Show More

55 views 1 answer







Regulating transformers are used in power systems for control of : a) voltage b) power factor c) power flow d) all of the above
Last Answer : Regulating transformers are used in power systems for control of :  power flow 

Show More

1.1k views 1 answer







Protective relays are devices that detect abnormal conditions in electrical circuits by measuring (a) current during abnormal condition (b) voltage during abnormal condition (c) constantly the electrical quantities which differ during normal and abnormal conditions (d) none of the above
Last Answer : (c) constantly the electrical quantities which differ during normal and abnormal conditions

Show More

48 views 1 answer






Show More⇦ PreviousNext ⇨