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Answer :

The power measurement in a balanced 3-phase circuit can be done by: One wattmeter method, Two wattmeter method, Three wattmeter method.

Related questions

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

Last Answer : In the case of power measurement by two wattmeter method in a balanced 3Φ system with a pure inductive load both the Wattmeter will indicate the same but of opposite sign.

Description : For power measurement of three phase circuit by two wattmeter method, when the value of power factor is less than 0.5 lagging:

Last Answer : For power measurement of three phase circuit by two wattmeter method, when the value of power factor is less than 0.5 lagging: One of the wattmeter connections will have to be reversed

Description : The minimum number of wattmeter(s) required to measure 3-phase, 3-wire balanced or unbalanced power is  A) 1 B) 2 C) 3 D) 4

Last Answer : B

Description : Measurement of power and power factor of a 3-phase system by two wattmeter method can be obtained in case of  1. Balanced load and balanced source  2. Balanced source with 3-phase 3-wire unbalanced load  3. Unbalanced source with 3-phase 3 ... b) 2, 3 and 5 (c) 1, 2, 3, 4 and 5 (d) 1, 2, 3 and 5 

Last Answer : Measurement of power and power factor of a 3-phase system by two wattmeter method can be obtained in case of  1. Balanced load and balanced source  2. Balanced source with 3-phase 3-wire unbalanced load  3. Unbalanced source with 3- ... b) 2, 3 and 5 (c) 1, 2, 3, 4 and 5 (d) 1, 2, 3 and 5 

Description : In a 3-phase power measurement by two wattmeter method the reading of one of the wattmeter was zero. The power factor of the load must be?

Last Answer : In a 3-phase power measurement by two wattmeter method the reading of one of the wattmeter was zero. The power factor of the load must be 0.5.

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.

Description : In a balanced 3 -phase 200 V circuit, the line current is 115.5 A. When the power is measured by two wattmeter method, one of the wattmeters reads 20 kW and the other one reads zero. What is the power factor of the load ?

Last Answer : In a balanced 3 -phase 200 V circuit, the line current is 115.5 A. When the power is measured by two wattmeter method, one of the wattmeters reads 20 kW and the other one reads zero. What is the power factor of the load ?  0.5

Description : Two wattmeters connected to measure the power input to a balanced three-phase circuit indicate 4.5 KW and 3 KW respectively. Find the power factor of the circuit. A. 0.7 B. 0.8 C. 0.95 D. 0 

Last Answer : Two wattmeters connected to measure the power input to a balanced three-phase circuit indicate 4.5 KW and 3 KW respectively. Find the power factor of the circuit.  0.95

Last Answer : The absolute measurement of resistance is done by Lorenz method.

Last Answer : The power of a n-phase circuit can be measured by using a minimum of (n - 1) wattmeter elements

Description : Draw a neat sketch and explain the use of CT and PT for measurement of power in a single-phase circuit?

Last Answer : If wattmeter of proper range is not available or if voltage and current ranges are high we can usr CT and PT of suitable ratio. Connect the CT and PT as shown in figure. The reading of wattmeter can be multiplied by the ratio to get the actual power.   

Description : Draw the circuit diagram for:- i) Measurement of active power in 3-phase load circuit using two wattmeter. ii) Measurement of reactive power in 3-phase load circuit using one wattmeter.

Last Answer : (i) Measurement of active power in 3- phase load circuit using two- wattmeter: (ii) Measurement of reactive power in 3- phase load circuit using one wattmeter

Description : Draw and explain the circuit diagram for measurement of single phase power using dynamometer type wattmeter. 

Last Answer : Circuit diagram for measurement of single phase power using dynamometer type wattmeter: Explanation: It consists of two stationary coils, called current coils and one moving coil, called voltage or ... i.e. power. The meter can be calibrated directly to indicate the power in watts. 

Description : List any two methods of reactive power measurement in 3 phase circuit.

Last Answer : Methods of reactive power measurement in 3 phase circuit: (i) Two single phase wattmeter method (ii) One single phase wattmeter method

Description : Define balanced and unbalanced load in three phase circuit.

Last Answer : Balanced Load: When all the imedances of 3 phases are equal in magnitude and of same nature then load is said to be balanced.  Unbalanced Load: When all the imedances of 3 phases are not equal in magnitude and of different nature then load is said to be unbalanced.

Description : In the measurement of power by two wattmeter method, when the readings of the two wattmeters are equal, the power factor is (A) Zero (B) Leading (C) Lagging (D) Unity

Last Answer : In the measurement of power by two wattmeter method, when the readings of the two wattmeters are equal, the power factor is Unity

Last Answer : Commonly used instruments in power system measurement are induction.

Description : Which of the following instruments can be used for measurement of very high value resistances such as insulation resistance in industries? A) Wheatstone bridge B) Megger C) Ohm-meter D) Resistive potentiometer 

Last Answer : Which of the following instruments can be used for measurement of very high value resistances such as insulation resistance in industries? A) Wheatstone bridge B) Megger C) Ohm-meter D) Resistive potentiometer 

Description : The function of measurement system is/are _____.

Last Answer : The function of measurement system are indicating, recording and controlling function.

Description : The measurement range of an ammeter can be increased by using a:

Last Answer : The measurement range of an ammeter can be increased by using a: low resistance in shunt

Description : Clamp on ammeter is used for measurement of:

Last Answer : Clamp on ammeter is used for measurement of: large alternating currents

Description : Weins bridge is used for measurement of frequency in the applied voltage waveform is measurement of frequency in the applied voltage waveform is   (A)sinusoidal (B) square (C) rectangular (D) triangular

Last Answer : Weins bridge is used for measurement of frequency in the applied voltage waveform is measurement of frequency in the applied voltage waveform is sinusoidal 

Description : Integrating principle in the digital measurement is the conversion of   (a) Voltage to time (b) Voltage to frequency (c) Voltage to current (d) Current to voltage

Last Answer : Integrating principle in the digital measurement is the conversion of Voltage to frequency

Description : For measurement of radio frequency ac signals __________ type meter is used

Last Answer : For measurement of radio frequency ac signals thermo-couple type meter is used

Description : Measurement of a non -electrical quantity involves the following four subsystems:  a) amplifier block b) display block c) instrumentation block d) transducer block  The correct, sequence in which these block occur is  (1) d,a,c,b (2) d, c, a, b (3) a, c, b, d (4) a, b, c, d

Last Answer : Measurement of a non -electrical quantity involves the following four subsystems:  a) amplifier block b) display block c) instrumentation block d) transducer block  The correct, sequence in which these block occur is d,a,c,b

Description : The bridge most suited for measurement of a four-terminal resistance in the range of 0.001 Ohm to 0.1 Ohm (A) Wien’s bridge (B) Kelvin double bridge (C) Maxwell’s bridge (D) Shering Bridge

Last Answer : The bridge most suited for measurement of a four-terminal resistance in the range of 0.001 Ohm to 0.1 Ohm (A) Wien’s bridge (B) Kelvin double bridge (C) Maxwell’s bridge (D) Shering Bridge

Description : Accurate measurement of very low resistances is possible with (A) Megger (B) Wheatstone Bridge (C) Kelvin’s Double Bridge (D) Wagner’s Earthing Device

Last Answer : Accurate measurement of very low resistances is possible with Kelvin’s Double Bridge

Last Answer : A measure of the reproducibility of measurement is known as Precision.

Last Answer : MISC meter not recommended for DC measurement because the error is high due to the hysteresis effect.

Last Answer : Ryall crest voltmeter is used for measurement of High AC voltage.

Last Answer : An instrument to be used for measurement and control should preferably have Linear output and fast response

Last Answer : Kelvin double bridge is best suited for the measurement of: Low resistance

Last Answer : Megger is an instrument used for the measurement of: High resistance and insulation resistance

Last Answer : Hay’s Bridge is suitable for the measurement of: Inductances with Q>10.

Last Answer : For measurement of inductance having high value, we should use Hay's bridge.

Last Answer : For measurement of mutual inductance we can use Heaviside bridge.

Description : Total instantaneous power supplied by a 3-phase ac supply to a balanced R-L load is

Last Answer : Total instantaneous power supplied by a 3-phase ac supply to a balanced R-L load is constant

Description : Two wattmeter method is employed to measure power in a 3 -phase balanced system with the current coil connected in the A and C lines. The phase sequence is ABC. If the wattmeter with its current coil in A -phase line reads zero, then the power factor of the 3 -phase load will be

Last Answer : Two wattmeter method is employed to measure power in a 3 -phase balanced system with the current coil connected in the A and C lines. The phase sequence is ABC. If the wattmeter with its current coil in A -phase line reads zero, then the power factor of the 3 -phase load will be 0.5 lagging.

Description : Two wattmeters are used to measure the power in a 3 -phase balanced system. What is the power factor of the load when one wattmeter reads twice the other ?  (a) 0 (b) 0.5 (c) 0.866 (d) 1

Last Answer : Two wattmeters are used to measure the power in a 3 -phase balanced system. What is the power factor of the load when one wattmeter reads twice the other ?  0.866

Description : A alternator is delivering power to a balanced load at unit power factor. The phase angle between the line voltage and the line current is? (A) 90° (B) 60° (C) 30° (D) 0° 

Last Answer : A alternator is delivering power to a balanced load at unit power factor. The phase angle between the line voltage and the line current is 30°

Description : While measuring power in a three phase load by two wattmeter method, the reading of two wattmeter are equal and opposite, when (a) load is balanced (b) power factor is unity (c) phase angle is between 60° to 90° (d) the load is purely inductive 

Last Answer :  Option (d)  Load is purely inductive 

Description : The power delivered to a 3-phase load can be measured by the use of two wattmeters only when the  (a) load is unbalanced (b) load is balanced (c) three phase load is connected to the source through three wires (d) three phase load is connected to the source through four wires

Last Answer : The power delivered to a 3-phase load can be measured by the use of two wattmeters only when the three phase load is connected to the source through three wires 

Last Answer : The power factor of a single phase load can be calculated if the instruments available are three ammeters or three voltmeters.

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

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

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

Description : State any two disadvantages of one wattmeter method of measurement of 3 phase power.

Last Answer : State any two disadvantages of one wattmeter method of measurement of 3 phase power. Disadvantages of one wattmeter method:- 1. Only used for balanced load 2. It can not be used for ... connection then neutral point must be available 4. Delta connection must be opened to connect current coil.

Description : During Phase 2 of action potential in cardiac cell, depolarizing current through calcium channels is balanced by (a) Delayed rectifier potassium current (b) outward chloride channel (c) Both (a) and (b) (d) None of the above

Last Answer : Ans: A

Description : In the phase shift method, How many circuits must be balanced? A. None of these B. 1 C. 4 D. 2

Last Answer : D. 2