Power (P) in a 3 phase circuit with two watt meters at unity power factor is (W1 & W2 = watt meter readings)

Power (P) in a 3 phase circuit with two watt meters at unity power factor is (W1 & W2 = watt meter readings)
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Power (P) in a 3 phase circuit with two watt meters at unity power factor is P = W1 + W2 (W1 & W2 = watt meter readings)

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The two watt meters measurement the ratio of two meter readings is –(1-sqrt3):( 1+sqrt3) then the power factor is a) 1 b) 0.866 c) 0.707 d) 0

Description : The two watt meters measurement the ratio of two meter readings is –(1-sqrt3):( 1+sqrt3) then the power factor is a) 1 b) 0.866 c) 0.707 d) 0

Last Answer : Ans: 0.707

Consider the fractional knapsack instance n = 4, (p1, p2, p3, p4) = (10, 10, 12, 18), (w1, w2, w3, w4) = (2, 4, 6, 9) and M = 15. The maximum profit is given by (Assume p and w denotes profit and weight of objects respectively) (A) 40 (B) 38 (C) 32 (D) 30

Description : Consider the fractional knapsack instance n = 4, (p1, p2, p3, p4) = (10, 10, 12, 18), (w1, w2, w3, w4) = (2, 4, 6, 9) and M = 15. The maximum profit is given by (Assume p and w denotes profit and weight of objects respectively) (A) 40 (B) 38 (C) 32 (D) 30

Last Answer : (B) 38

If l1 and l2 are the lengths of long and short spans of a two way slab simply supported on four edges and carrying a load w per unit area, the ratio of the loads split into w1 and w2acting on strips parallel to l2 and l1 is (A) w1/w2 = l2/l1 (B) w1/w2 = (l2/l1)² (C) w1/w2 = (l2/l1)3 (D) w1/w2 = (l2/l1)

Description : If l1 and l2 are the lengths of long and short spans of a two way slab simply supported on four edges and carrying a load w per unit area, the ratio of the loads split into w1 and w2acting on strips parallel to l2 and l1 is (A) ... l1 (B) w1/w2 = (l2/l1)² (C) w1/w2 = (l2/l1)3 (D) w1/w2 = (l2/l1)

Last Answer : Answer: Option D

Consider following schedules involving two transactions: S1: r1(X); r1(Y); r2(X); r2(Y); w2(Y); w1(X) S2: r1(X); r2(X); r2(Y); w2(Y); r1(Y); w1(X) Which of the following statement is true? (1) Both S1 and S2 are conflict serializable. (2) S1 is conflict serializable and S2 is not conflict serializable. (3) S1 is not conflict serializable and S2 is conflict serializable. (4) Both S1 and S2 are not conflict serializable.

Description : Consider following schedules involving two transactions: S1: r1(X); r1(Y); r2(X); r2(Y); w2(Y); w1(X) S2: r1(X); r2(X); r2(Y); w2(Y); r1(Y); w1(X) Which of the following ... . (3) S1 is not conflict serializable and S2 is conflict serializable. (4) Both S1 and S2 are not conflict serializable.

Last Answer : S1 is not conflict serializable and S2 is conflict serializable.

An artificial neurons receives n inputs x1, x2,...,xn with weights w1,w2,...,wn attached to the input links. The weighted sum ............... is computed to be passed on to a non-linear filter ϕ called activation function to release the output. (A) Σ wi (B) Σ xi (C) Σ wi + Σ xi (D) Σ wi . Σ xi

Description : An artificial neurons receives n inputs x1, x2,...,xn with weights w1,w2,...,wn attached to the input links. The weighted sum ............... is computed to be passed on to a non-linear filter ϕ called activation function to release the output. (A) Σ wi (B) Σ xi (C) Σ wi + Σ xi (D) Σ wi . Σ xi

Last Answer : (D) Σ wi . Σ xi

A perceptron has input weights W1 = -3.9 and W2 = 1.1 with threshold value T = 0.3. What output does it give for the input x1 = 1.3 and x2 = 2.2? (A) -2.65 (B) -2.30 (B) 0 (D) 1

Description : A perceptron has input weights W1 = -3.9 and W2 = 1.1 with threshold value T = 0.3. What output does it give for the input x1 = 1.3 and x2 = 2.2? (A) -2.65 (B) -2.30 (B) 0 (D) 1

Last Answer : Answer: C

What is the power factor when a single phase watt meter operating on 200 V and 5 A for 5 hours makes 2016

Description : What is the power factor when a single phase watt meter operating on 200 V and 5 A for 5 hours makes 2016 revolutions and the meter constant in revolution is 420? A) 0.04 B) 1.04 C) 0.96 D) None of these

Last Answer : What is the power factor when a single phase watt meter operating on 200 V and 5 A for 5 hours makes 2016 revolutions and the meter constant in revolution is 420? A) 0.04 B) 1.04 C) 0.96 D) None of these

The meter constant of a single-phase 230 V induction watt hour meter is 400 revolutions per kWh....

Description : The meter constant of a single-phase 230 V induction watt hour meter is 400 revolutions per kWh. The speed of the meter disc for a current of 10 A of 0.9 pf lagging will be

Last Answer : The meter constant of a single-phase 230 V induction watt hour meter is 400 revolutions per kWh. The speed of the meter disc for a current of 10 A of 0.9 pf lagging will be 13.80 rpm

A 230 V/460 V single-phase transformer operating at 20 A and unity power factor has primary referred

Description : A 230 V/460 V single-phase transformer operating at 20 A and unity power factor has primary referred resistance of 0.2 Ω and reactance of 0.5 Ω. The approximate primary induced emf is (A) 216 V (B) 226 V (C) 234 V (D) 236 V

Last Answer : A 230 V/460 V single-phase transformer operating at 20 A and unity power factor has primary referred resistance of 0.2 Ω and reactance of 0.5 Ω. The approximate primary induced emf is 226 V

When troubleshooting electronic equipment, you should use a high impedance multimeter ________________. A. to prevent excess current flow through the meter that would damage it B. for AC measurements only and a low resistance meter for DC measurements C. whenever a low impedance meter is not available, regardless of the components being tested D. so as not to load down the circuit and obtain erroneous voltage readings

Description : When troubleshooting electronic equipment, you should use a high impedance multimeter ________________. A. to prevent excess current flow through the meter that would damage it B. for AC measurements only ... being tested D. so as not to load down the circuit and obtain erroneous voltage readings

Last Answer : Answer: D

In the measurement of power of balanced load by two wattmeter method in a 3-phase circuit, The readings

Description :  In the measurement of power of balanced load by two wattmeter method in a 3-phase circuit, The readings of the wattmeters are 4 kW and 2 kW respectively, the later is being taken after reversing the connections of current coil. the ... kVAR B) 0.2 & 6 √3 kVAR C) 0.32 & 2 kVAR D) 0.32 & 2 √3 kVAR

Last Answer :  In the measurement of power of balanced load by two wattmeter method in a 3-phase circuit, The readings of the wattmeters are 4 kW and 2 kW respectively, the later is being taken after reversing the ... of current coil. the power factor and reactive power of the load is 0.2 & 6 √3 kVAR

Annual total energy & production chart smoothens out ____ in energy timing of meter readings. a) Errors b) Efficiency c) Accuracy. d) Repeatability

Description : Annual total energy & production chart smoothens out ____ in energy timing of meter readings. a) Errors b) Efficiency c) Accuracy. d) Repeatability

Last Answer : errors

State the application of phase sequence indicator; clip on ammeter, frequency meter & P.F. meter.

Description : State the application of phase sequence indicator; clip on ammeter, frequency meter & P.F. meter.

Last Answer : Phase Sequence Indicator:  1. For finding correct phase sequence of supply  2. For obtaining exact instant of parallel operation of alternators.  3. For obtaining reversal of rotation ...  4. In electroplating industries   5. In various processes industries for measuring power factor

Which of the following meters uses a shunt connected in series with the load, but parallel with the meter movement? A. voltmeter B. power factor meter C. wattmeter D. ammeter

Description : Which of the following meters uses a shunt connected in series with the load, but parallel with the meter movement? A. voltmeter B. power factor meter C. wattmeter D. ammeter

Last Answer : Answer: D

Which of the listed meters uses a shunt connected in series with the load, but parallel with the meter movement? A. Voltmeter B. Power factor meter C. Ammeter D. Wattmeter

Description : Which of the listed meters uses a shunt connected in series with the load, but parallel with the meter movement? A. Voltmeter B. Power factor meter C. Ammeter D. Wattmeter

Last Answer : Answer: C

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%.

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%.

A 3-phase 11 kV generator feeds power to a constant power unity power factor load of 100 MW through a

Description : A 3-phase 11 kV generator feeds power to a constant power unity power factor load of 100 MW through a 3-phase transmission line. The line-to line voltage at the terminals of the machine is maintained constant at 11 kV. The per ... 11 kV is  (A) 100 MVAR (B) 10.1 MVAR (C) -100 MVAR (D) -10.1 MVAR

Last Answer : A 3-phase 11 kV generator feeds power to a constant power unity power factor load of 100 MW through a 3-phase transmission line. The line-to line voltage at the terminals of the machine is maintained ... load to increase the line-to-line voltage at the load terminals to 11 kV is -10.1 MVAR

A simple phase transformer has a maximum efficiency of 90% at full load and unity power factor. Efficiency at

Description : A simple phase transformer has a maximum efficiency of 90% at full load and unity power factor. Efficiency at half load at the same power factor is  (A) 86.7% (B) 88.26% (C) 88.9% (D) 87.8%

Last Answer : A simple phase transformer has a maximum efficiency of 90% at full load and unity power factor. Efficiency at half load at the same power factor is 87.8%

A three-phase synchronous motor connected to ac mains is running at full load and unity power factor.

Description : A three-phase synchronous motor connected to ac mains is running at full load and unity power factor. lf its shaft load is reduced by half and field current is held constant then its new power factor will be

Last Answer : Leading

In an alternator at lagging power factor the generated voltage per phase as compared to that at unity power factor?

Description : In an alternator at lagging power factor the generated voltage per phase as compared to that at unity power factor?

Last Answer : In an alternator, at lagging power factor the generated voltage per phase as compared to that at unity power factor must be more than terminal voltage.

The power consumed by a balanced 3-ph load is measured by two-wattmeter method. The meter readings are

Description : The power consumed by a balanced 3-ph load is measured by two-wattmeter method. The meter readings are 8 kW and 4 kW. The power factor of the load is (A) zero (B) 0.5 (C) between zero and 0.5 (D) between 0.5 and unity

Last Answer : The power consumed by a balanced 3-ph load is measured by two-wattmeter method. The meter readings are 8 kW and 4 kW. The power factor of the load is between 0.5 and unity

With a neat sketch explain working of 1 phase dynamometer type power factor meter.

Description : With a neat sketch explain working of 1 phase dynamometer type power factor meter.

Last Answer : Working of 1 phase dynamometer type power factor meter : The current coil is connected in series with load. Two pressure coils marked as A and B are connected across the supply terminals ... becomes stationary and the pointer shows steady deflection corresponding to the power factor of the load. 

When the voltage and the current developed in an AC circuit reach their peak values at the same time, the power factor is considered to be _____________. A. lagging B. leading C. unity D. infinity

Description : When the voltage and the current developed in an AC circuit reach their peak values at the same time, the power factor is considered to be _____________. A. lagging B. leading C. unity D. infinity

Last Answer : Answer: C

At dead short circuit at terminals of Alternator then the current I is a) ZPF Lag b) ZPF lead c) Unity power factor d) 0.8 Power factor lag

Description : At dead short circuit at terminals of Alternator then the current I is a) ZPF Lag b) ZPF lead c) Unity power factor d) 0.8 Power factor lag

Last Answer : Ans: ZPF Lag

A single phase wattmeter rated for 500 V; 5A is having full scale deflection of 1000 watt. What is multiplying factor of the wattmeter?

Description : A single phase wattmeter rated for 500 V; 5A is having full scale deflection of 1000 watt. What is multiplying factor of the wattmeter?

Last Answer : Answer :

The unit of power in S.I. units is (A) Newton meter (B) Watt (C) Joule (D) Kilogram meter/sec

Description : The unit of power in S.I. units is (A) Newton meter (B) Watt (C) Joule (D) Kilogram meter/sec

Last Answer : (B) Watt

A two -winding single phase transformer has a voltage regulation of 4.5% at full - load and unity power ...

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 lagging power-factor, the voltage regulation will be: (A) 4.5% (B) less than 4.5% (C) more than 4.5% (D) none of the above

Last Answer : 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 lagging power-factor, the voltage regulation will be: more than 4.5%

Which of the meters listed should only be used after a circuit has been electrically disconnected? A. Wattmeter B. Frequency meter C. Ammeter D. Ohmmeter

Description : Which of the meters listed should only be used after a circuit has been electrically disconnected? A. Wattmeter B. Frequency meter C. Ammeter D. Ohmmeter

Last Answer : Answer: D

A synchronous motor is operating on no-load at unity power factor. If the field current is increased, power factor will become (A) Leading & current will decrease (B) Lagging & current will increase. (C) Lagging & current will decrease. (D) Leading & current will increase.

Description : A synchronous motor is operating on no-load at unity power factor. If the field current is increased, power factor will become (A) Leading & current will decrease (B) Lagging & current will increase. (C) Lagging & current will decrease. (D) Leading & current will increase.

Last Answer : Ans: A Initially synchronous motor is operating at no load and unity power factor. When field current increases, the excitation will increase. Therefore, p.f will be leading and current will be I CosΦ < I

At which frequency ratio, phase angle increases as damping factor increases? A. When frequency ratio is less than unity B. When frequency ratio is more than unity C. When frequency ratio is zero D. All of the above

Description : At which frequency ratio, phase angle increases as damping factor increases? A. When frequency ratio is less than unity B. When frequency ratio is more than unity C. When frequency ratio is zero D. All of the above

Last Answer : A. When frequency ratio is less than unity

As shown in the illustration, what maintenance would be required of the circuit components? EL-0058 A. Change out both 'C' units monthly. B. Clean the glass surrounding 'E1' & 'E2' as needed. C. File the points at the upper end of 'G' every six months. D. Take megger readings on 'E1' & 'E2' windings quarterly.

Description : As shown in the illustration, what maintenance would be required of the circuit components? EL-0058 A. Change out both 'C' units monthly. B. Clean the glass surrounding 'E1' & 'E2' as needed. C. File ... upper end of 'G' every six months. D. Take megger readings on 'E1' & 'E2' windings quarterly.

Last Answer : Answer: B

In preparing to take insulation resistance readings on a main generator, the windings should be grounded for about 15 minutes prior to the test to _____________. A. allow accurate zeroing of the meter B. help the windings to cool to ambient temperature C. release any residual capacitive charge from the windings D. help the windings to cool to the same temperature as the ground test connection

Description : In preparing to take insulation resistance readings on a main generator, the windings should be grounded for about 15 minutes prior to the test to _____________. A. allow accurate zeroing of the meter ... the windings D. help the windings to cool to the same temperature as the ground test connection

Last Answer : Answer: C

Before using a volt-ohmmeter to measure resistance readings, you should _____________. A. replace all batteries B. test the insulation resistance of the leads C. make sure the test leads do not touch D. hold the leads together and 'zero' the meter

Description : Before using a volt-ohmmeter to measure resistance readings, you should _____________. A. replace all batteries B. test the insulation resistance of the leads C. make sure the test leads do not touch D. hold the leads together and 'zero' the meter

Last Answer : Answer: D

The average mean velocity of a stream having depth h, may be obtained by taking the average of the readings of a current meter at a depth of (A) 0.1 h and 0.9 h (B) 0.2 h and 0.8 h (C) 0.3 h and 0.7 h (D) 0.4 h and 0.6 h

Description : The average mean velocity of a stream having depth h, may be obtained by taking the average of the readings of a current meter at a depth of (A) 0.1 h and 0.9 h (B) 0.2 h and 0.8 h (C) 0.3 h and 0.7 h (D) 0.4 h and 0.6 h

Last Answer : Answer: Option B

To determine the discharge at a section in a stream from its rating curve, the required data are (i) Slope of water surface at the section (ii) Stage at the section (ii) Current meter readings at the section The correct answer is (A) (i) and (ii) (B) (ii) and (iii) (C) Only (ii) (D) Only (iii)

Description : To determine the discharge at a section in a stream from its rating curve, the required data are (i) Slope of water surface at the section (ii) Stage at the section (ii) Current meter readings at the section The correct ... ) (i) and (ii) (B) (ii) and (iii) (C) Only (ii) (D) Only (iii)

Last Answer : Answer: Option C

Besides setting up the meter for expected voltage ranges, what must be strictly observed when taking dc voltage readings?

Description : Besides setting up the meter for expected voltage ranges, what must be strictly observed when taking dc voltage readings?

Last Answer : Polarit

At what point on a meter movement are the most accurate readings taken?

Description : At what point on a meter movement are the most accurate readings taken?

Last Answer : Midscale.

Define power factor. State its significance. What is the condition for unity power factor ?

Description : Define power factor. State its significance. What is the condition for unity power factor ? 

Last Answer : Definition of Power factor: Power factor is cosine of angle between voltage and current.  OR Power factor is the ratio of active power to the apparent power .  Significance of Power factor:  ... When cosine of angle between voltage and current is zero. When R = Z  When KW = KVA 

What will be the efficiency when the transformer operates at unity power factor and 60% of full load

Description : What will be the efficiency when the transformer operates at unity power factor and 60% of full load 

Last Answer : What will be the efficiency when the transformer operates at unity power factor and 60% of full load 96.5%

A synchronous generator is feeding power to infinite bus bars at unity power factor. Its excitation is now...

Description : A synchronous generator is feeding power to infinite bus bars at unity power factor. Its excitation is now increased. It will feed (a) The same power but at a leading power factor (b) The same power ... a lagging power factor (c) More power at unity power factor (d) Less power at unity power factor

Last Answer : A synchronous generator is feeding power to infinite bus bars at unity power factor. Its excitation is now increased. It will feed The same power but at a lagging power factor 

A 10,000-watt motor operates an elevator weighing 5000 newtons. Assuming no frictional losses, how high is the elevator raised in 10 seconds. Is it raised: w) 2 meters x) 20 meters y) 50 meters z) 100 meters

Description : A 10,000-watt motor operates an elevator weighing 5000 newtons. Assuming no frictional losses, how high is the elevator raised in 10 seconds. Is it raised: w) 2 meters x) 20 meters y) 50 meters z) 100 meters

Last Answer : ANSWER: X -- 20 METERS

Induction watt-hour meters are free from

Description : Induction watt-hour meters are free from (a) phase (b) creeping (c) temperature (d) frequency

Last Answer : b

In a 3-phase power measurement by two wattmeter method, both the wattmeters had identical readings...

Description : In a 3-phase power measurement by two wattmeter method, both the watt meters had identical readings. The power factor of the load was?

Last Answer : In a 3-phase power measurement by two wattmeter method, both the watt meters had identical readings. The power factor of the load was unity.

In the plot of Z(compressibility factor) vs P, Z attains a value of unity at a certain pressure. What does this signify?

Description : In the plot of Z(compressibility factor) vs P, Z attains a value of unity at a certain pressure. What does this signify?

Last Answer : Ans. It implies that at this value of pressure attractive and repulsive forces balance each other. Below this pressure attraction dominates and Z < 1. Above this pressure repulsion dominates and Z > 1.

In a dynamometer 3-phase power factor meter, the planes of the two moving coils are at?

Last Answer : In a dynamometer 3-phase power factor meter, the planes of the two moving coils are at 120°.

In a single phase power factor meter the phase difference between the currents in the two pressure coils is?

Last Answer : In a single phase power factor meter the phase difference between the currents in the two pressure coils is exactly 90°.

The two pressure coils of a single phase power factor meter have?

Last Answer : The two pressure coils of a single phase power factor meter have the same dimensions and the same number of turns.

A three-phase alternator operates at 450 volts with a power factor of 0.8. If the ammeter indicates 250 amperes, what should be the KW meter reading? A. 90.00 KW B. 127.27 KW C. 155.70 KW D. 194.85 KW

Description : A three-phase alternator operates at 450 volts with a power factor of 0.8. If the ammeter indicates 250 amperes, what should be the KW meter reading? A. 90.00 KW B. 127.27 KW C. 155.70 KW D. 194.85 KW

Last Answer : Answer: C

A three-phase alternator is developing 300 amps, with a 0.8 power factor, at 450 volts. The true indicated power on the kilowatt meter, located on the main switchboard, will be ____________. A. 133 kw B. 155 kw C. 187 kw D. 212 kw

Description : A three-phase alternator is developing 300 amps, with a 0.8 power factor, at 450 volts. The true indicated power on the kilowatt meter, located on the main switchboard, will be ____________. A. 133 kw B. 155 kw C. 187 kw D. 212 kw

Last Answer : Answer: C

A three-phase alternator is operating at 450 volts with the switchboard ammeter indicating 300 amps. The kw meter currently indicates 163.6 KW, with a power factor of 0.7. If the power factor increases to 0.8, the KW meter would then read ____________. A. 181.4 KW B. 186.8 KW C. 194.2 KW D. 201.4 KW

Description : A three-phase alternator is operating at 450 volts with the switchboard ammeter indicating 300 amps. The kw meter currently indicates 163.6 KW, with a power factor of 0.7. If the power factor increases to 0.8, the KW meter would then read ____________. A. 181.4 KW B. 186.8 KW C. 194.2 KW D. 201.4 KW

Last Answer : Answer: B