Define: primary and secondary distribution system
Last Answer : i) Primary Distribution: It is a 3-phase, 3-wire transmission line connected in between receiving substation to Distribution substation. OR It is link between receiving substation & ... substation to consumer line. OR It is link between distribution transformer substation & consumer.
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asked
May 22, 2020
by
anonymous

Compare primary and secondary instruments.
Last Answer : Primary instruments Secondary instruments Gives magnitude of quantity in terms of physical constants of instrument Gives reading directly of the quantity measured. Need no calibration ... . e.g. magnetic meter, induction meter, hotwire meter and electrostatic meter
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90 views
1 answer
asked
Sep 6, 2018
by
anonymous

Last Answer : Primary winding of a transformer could either be a low voltage or high voltage winding.
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86 views
1 answer
asked
Mar 19, 2018
by
anonymous

When secondary of a current transformer is open-circuited its iron core will be?
Last Answer : When secondary of a current transformer is open-circuited its iron core will be hot because of heavy iron losses taking place in it due to high flux density.
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165 views
1 answer
asked
Mar 19, 2018
by
anonymous

The secondary of a current transformer is always short-circuited under operating conditions because it?
Last Answer : The secondary of a current transformer is always short-circuited under operating conditions because it avoids core saturation and high voltage induction.
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107 views
1 answer
asked
Mar 19, 2018
by
anonymous

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
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223 views
1 answer
asked
May 8, 2018
by
anonymous

Write difference between absolute & secondary instrument.
Last Answer : Absolute Instrument Secondary Instrument 1. These give magnitude of quantity in terms physical constants of instruments 1. These give reading directly of the quantity at the time of ... Raleigh current balance. 6. Examples - ammeter, voltmeter, amperehour meter, wattmeter etc.
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6.1k views
1 answer
asked
Sep 5, 2018
by
anonymous

Increasing the number of turns of wire on the secondary of a transformer will (A) Decrease the secondary current (B) Increase the primary current (C) Have no effect on the secondary current (D) Increase the secondary current
Last Answer : Increasing the number of turns of wire on the secondary of a transformer will Decrease the secondary current
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1.3k views
1 answer
asked
May 8, 2018
by
anonymous

If an unsymmetrical line to ground fault occurs at the secondary terminals of a delta/star, ungrounded transformer, then (A) zero sequence currents are present on both sides of the transformer (B) ... side (D) zero sequence currents are present on the primary side but not on the secondary side
Last Answer : If an unsymmetrical line to ground fault occurs at the secondary terminals of a delta/star, ungrounded transformer, then zero sequence currents are absent on both sides of the transformer
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228 views
1 answer
asked
Apr 29, 2018
by
anonymous

What is the mathematical relationship between resistance and conductance?
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96 views
0 answers
asked
Jun 29, 2019
by
anonymous

What is the relationship between power and resistance?
Last Answer : P = I2R Where P = power I = Current R = Resistance
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71 views
2 answers
asked
Mar 15, 2018
by
anonymous

A single phase transformer has resistance and reactance of 0.2 pu and 0.6 pu respectively. Its pu voltage regulation at 0.8 pf lagging would he
Last Answer : A single phase transformer has resistance and reactance of 0.2 pu and 0.6 pu respectively. Its pu voltage regulation at 0.8 pf lagging would he 0.52
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367 views
1 answer
asked
May 3, 2018
by
anonymous

What happens to the voltage in the secondary when the frequency of the supply in the primary is decreased? A) It increases B) It decreases C) It remains the same D) Cannot say unless the actual percentage increase in the frequency is known
Last Answer : What happens to the voltage in the secondary when the frequency of the supply in the primary is decreased? A) It increases B) It decreases C) It remains the same D) Cannot say unless the actual percentage increase in the frequency is known
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119 views
1 answer
asked
Apr 29, 2018
by
anonymous

Last Answer : An ideal transformer has infinite values of primary and secondary inductances. The statement is false.
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324 views
1 answer
asked
Mar 19, 2018
by
anonymous

Write example of each type (i) Primary transducer (ii) Active transducer (iii) Electrical transducer (iv) Digital transducer
Last Answer : (i) Active transducer:-Thermocouple, piezoelectric, photovoltaic cell (ii) Primary transducer:- Bourdon tube, bellows, (iii) Electrical transducer.:- LVDT,RVDT, Hall effect, strain gauge, ... , optical pyrometer, radiation pyrometer (iv) Digital transducer:- Linear Encoder, digital taco generator
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166 views
2 answers
asked
Aug 5, 2019
by
anonymous

Last Answer : The primary reason for low power factor is supply system is due to installation of induction motors.
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115 views
1 answer
asked
Mar 20, 2018
by
anonymous

What is the definition of a primary instrument?
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0 answers
asked
Mar 10, 2018
by
anonymous

Primary and Backup Protection
Last Answer : Primary and Backup Protection B,D,G,I are the primary protection. A,C,H,J are the backup protection. About 90% of faults are clear by Primary Protection. So ... ordinated backup (primary is at various station and backup is at control room with computer)
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401 views
1 answer
asked
Aug 9, 2017
by
anonymous

State the losses in secondary distribution system.
Last Answer : The losses in secondary distribution system: a) Technical losses: 1. Due to poor voltage 2. Due to unbalance load 3. Due poor quality of transformer & its components 4. Due to poor quality ... of induction type of energy meter. 3. Lack of administration. 4. Energy theft 5. Unmetered supply
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122 views
1 answer
asked
May 3, 2020
by
anonymous

State the meaning of secondary instrument. Classify secondary instruments.
Last Answer : Secondary instruments: - Gives reading directly of the quantity being measured. - Calibrated with respect to absolute instruments Classification of Secondary instruments: 1. Depending on the ... on permissible error: i) Standard meters ii) Substandard meters iii) First grade instruments.
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76 views
1 answer
asked
Sep 6, 2018
by
anonymous

State the meaning of absolute instrument and secondary instrument.
Last Answer : Absolute instruments: These instruments read the quantity under measurement indirectly i.e. in terms of deflection, degrees and meter constant. The actual value under measurement can be calculated ... of operation (b) Depending upon permissible percentage error. (c) Depending upon application.
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113 views
2 answers
asked
Sep 6, 2018
by
anonymous

Why CT is never operated with an open secondary ?
Last Answer : CT secondary should never be kept open because it will cause saturation of the core to a high level and very high voltage will appear across the secondary which can breakdown the insulation. One terminal of PT secondary is always grounded to avoid capacitive induction and for human safety
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92 views
2 answers
asked
Sep 6, 2018
by
anonymous

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
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580 views
1 answer
asked
May 8, 2018
by
anonymous

What do you mean by secondary instruments?
Last Answer : The instruments which will give the direct readings are called secondary instruments
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95 views
1 answer
asked
Mar 10, 2018
by
anonymous

What do you mean by exciting resistance and exciting reactance?
Last Answer : At no-load, a transformer behaves as a highly inductive load connected to the system which contains some resistance and inductance in parallel. The resistance is called exciting resistance R0 = V1/I w and reactance is called exciting reactance, X0 = V1/I mag
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183 views
2 answers
asked
Apr 28, 2020
by
anonymous

57 In a transformer the resistance between its primary and secondary is A. Zero B. 1Ω C. 1000 Ω D. Infinite
Last Answer : D. Infinite
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1 answer

50 The equivalent resistance of the primary of the transformer having K = 5, R1 = 0.1 ohm when referred to secondary becomes .....ohm A. 0.5 B. 0.02 C. 0.004 D. 2.5
Last Answer : A. 0.5
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847 views
1 answer

What current flows in the transformer primary when its secondary is open?
Last Answer : A. When the secondary is open, there is no current in the secondary of the transformer. The primary takes a small current I0) from the source called no-load current which has a magnetizing ... ) producing the magnetic flux and a working component (I0 cosθ0) supplying real power for iron losses.
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1 answer

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
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5 views
1 answer

In a Tap changing transformer on which side is the tap connected, primary side or secondary side?
Last Answer : A. Tapings are always connected to high voltage winding side, because of low current. If we connect tapings to low voltage side, sparks will produce while tap changing operation due to high current.
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1 answer

66 While conducting short-circuit test on a transformer the following side is short circuited A. High voltage side B. low voltage side C. primary side D. secondary side
Last Answer : B. Low voltage side
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59.An ideal transformer has infinite values of primary and secondary inductances. The statement is A. True B. False
Last Answer : B. False
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1 answer
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52 A transformer has 1000 primary turns, connected to 250V ac supply. To get 400V secondary voltage the no of secondary turns should be A. 1600 B. 250 C. 400 D. 1250
Last Answer : A. 1600
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1 answer

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
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1 answer

29.In transformer terminology, the ratio 20:1 indicates that A. there are 20 turns on primary one turn on secondary B. secondary voltage is 1/20th of the primary C. primary current is 20 times greater than the secondary current D. for every 0 turns on primary, there is one turn on secondary
Last Answer : A. there are 20 turns on primary one turn on secondary
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2 answers

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
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314 views
1 answer

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
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1 answer

The frequency of the secondary voltage of a transformer will be..... A. less than frequency of the primary voltage B. equal to the primary voltage C. greater than the frequency of the primary voltage D. much greater than the frequency of the primary voltage
Last Answer : B. Equal to the primary voltage
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1 answer

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
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1 answer

During short circuit test iron losses are negligible because A. The current on secondary side is negligible B. The voltage on secondary side does not vary C. The voltage applied on primary side is low D. Full-load current is not supplied to the transformer
Last Answer : C) the voltage applied on primary side is low
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51 views
1 answer

During short circuit test iron losses are negligible because A. The current on secondary side is negligible B. The voltage on secondary side does not vary C. The voltage applied on primary side is low D. Full-load current is not supplied to the transformer
Last Answer : C) the voltage applied on primary side is low
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4 views
1 answer

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 ... voltage applied on primary side is low D. Full-load current is not supplied to the transformer
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21 views
0 answers

Last Answer : Greater the secondary leakage flux less will be the secondary induced e.m.f.
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143 views
1 answer
asked
Mar 19, 2018
by
anonymous
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Last Answer : When a given transformer is run at its rated voltage but reduced frequency, its core flux density is increased.
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110 views
1 answer
asked
Mar 19, 2018
by
anonymous

The maximum load that a power transformer can carry is limited by its?
Last Answer : The maximum load that a power transformer can carry is limited by its voltage ratio.
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133 views
1 answer
asked
Mar 19, 2018
by
anonymous

Explain the effect of Harmonics on the Transformer.
Last Answer : Effect of Harmonics on the Transformer: 1. Core loss: Harmonic voltage increases the hysteresis and eddy current losses in the lamination. The amount of the core loss depends on ... small core vibrations. 5. Saturation problem: Sometimes additional harmonic voltage causes core saturation.
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127 views
1 answer
asked
May 22, 2020
by
anonymous

List two special feature of welding transformer.
Last Answer : Special features of welding transformer: i) It is a step down transformer that reduces the source voltage to a voltage desired according to the demands of the welding process. ii) Having large primary turns and less ... V ii) Secondary voltage - 40 to 60 V iii) Secondary current - 200 to 600 A
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148 views
1 answer
asked
May 22, 2020
by
anonymous

State two applications of isolation transformer
Last Answer : Applications of isolation transformer: i) Isolates the load equipment from supply ground: ii) Reduction of voltage spikes iii) It acts as a decoupling device. iv) Protects loads from harmonic distortion.
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54 views
1 answer
asked
May 22, 2020
by
anonymous

State why a transformer always have an efficiency of more than 90%.
Last Answer : As transformer is static device with no moving parts, the losses due to friction & windage are completely absent. Hence transformer has efficiency of more than 90%.
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269 views
1 answer
asked
May 22, 2020
by
anonymous

Equivalent circuit of transformer
Last Answer : Equivalent Circuit Diagram of Transformer Referred to Primary: V1 -Primary Input voltage I1 - Input Current I0- Exciting current/ No load current Im- Magnetizing component ... equivalent of secondary terminal voltage ZL- Load impedance ZL ′- Primary equivalent of load impedance
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381 views
2 answers
asked
May 17, 2020
by
anonymous
