For power measurement of three phase circuit by two wattmeter method, when the value of power factor

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

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Measurement of power and power factor of a 3-phase system by two wattmeter method can be

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 

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

In a 3-phase power measurement by two wattmeter method the reading of one of the wattmeter was zero...

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.

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 measurement of power by two wattmeter method, when the readings of the two

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

In the case of power measurement by two wattmeter method in a balanced 3Φ system with a pure inductive load

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.

While measuring power in a three phase load by two wattmeter method, the reading of two wattmeter are

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 

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.

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

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

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

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.

Explain the effect of power factor on wattmeter reading in two wattmeter method for power measurement.

Description : Explain the effect of power factor on wattmeter reading in two wattmeter method for power measurement.

Last Answer : Effect of P.F. on Reading of Wattmeter in Two Wattmeter Method:

The minimum number of wattmeter(s) required to measure 3-phase, 3-wire balanced or unbalanced power is

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

Consider the following statements 1) The compensating coil of a low power factor wattmeter compensates

Description : Consider the following statements  1) The compensating coil of a low power factor wattmeter compensates the effect of the impedance of the current coil ii) The compensating coil of a low power factor wattmeter compensates the effect ... C) Both (i) and (ii) are true D) Both (i) and (ii) are false

Last Answer : A

In a low power factor wattmeter the compensating coil is connected?

Last Answer : In a low power factor wattmeter the compensating coil is connected in series with pressure coil.

In a low power factor wattmeter the pressure coil is connected?

Last Answer : In a low power factor wattmeter the pressure coil is connected to the load side of the current coil.

The power measurement in a balanced 3-phase circuit can be done by:

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

In two -wattmeter method of power measurement, if one wattmeter shows negative reading, then the...

Description : In two -wattmeter method of power measurement, if one wattmeter shows negative reading, then the power factor of the circuit is treated as (A) Unity (B) Lagging (C) Leading (D) Zero

Last Answer : Lagging   power   factor.

The current coil of a wattmeter is connected to the CT of R-phase....

Description : The current coil of a wattmeter is connected to the CT of R-phase. The potential coil is connected across Y and B phases. The wattmeter measures

Last Answer : The current coil of a wattmeter is connected to the CT of R-phase. The potential coil is connected across Y and B phases. The wattmeter measures Reactive power of R phase.

The resistance in the circuit of the moving coil of a dynamometer wattmeter should be?

Last Answer : The resistance in the circuit of the moving coil of a dynamometer wattmeter should be high.

Illustrate how can you use a single-phase wattmeter to measure 3 phase reactive power in a circuit?

Description : Illustrate how can you use a single-phase wattmeter to measure 3 phase reactive power in a circuit?

Last Answer : We can measure reactive power of 3 phase circuit by dingle phase wattmeter by connecting the current coil in series with a line or load and connecting the pressure coil across the other two lines.  Reactive power = 3√ V * I * sinϕ Watts. 

Two wattmeter method is employed to measure power in a 3 -phase balanced system with the current coil ...

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.

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 power delivered to a three-phase load can be measured by the use of 2 wattmeter only when the

Description : The power delivered to a three-phase load can be measured by the use of 2 wattmeter only when the A. Load is balanced B. 3 -phase load is connected to the source through 3 wires C. Load is unbalanced D. 3 -phase load is connected to the source through 4 wires

Last Answer : The power delivered to a three-phase load can be measured by the use of 2 wattmeter only when the  Load is unbalanced

In dynamometer type of wattmeter, which of the coil is split up into two parts?

Description :  In dynamometer type of wattmeter, which of the coil is split up into two parts?

Last Answer :  In dynamometer type of wattmeter, which of the coil is split up into two parts?  current coil

The pressure coil of a dynamometer type wattmeter is

Description : The pressure coil of a dynamometer type wattmeter is  A) Highly inductive B) Highly resistive C) Purely resistive D) Purely inductive

Last Answer : highly resistive

A wattmeter is connected as shown in the figure. The wattmeter reads

Description : A wattmeter is connected as shown in the figure. The wattmeter reads 

Last Answer : A wattmeter is connected as shown in the figure. The wattmeter reads Power consumed by Z2

Poynting vector wattmeter is based on

Description : Poynting vector wattmeter is based on   (A) Seebeck effect (B) Ferranti effect (C) Induction effect (D) Hall effect

Last Answer : Poynting vector wattmeter is based on Induction effect 

The torque produced in wattmeter is proportional to

Description : The torque produced in wattmeter is proportional to

Last Answer : A

Wattmeter cannot be designed on the principle of

Last Answer : Wattmeter cannot be designed on the principle of moving iron instrument.

The pressure coil of a wattmeter should be connected on the supply side of the current coil when?

Last Answer : The pressure coil of a wattmeter should be connected on the supply side of the current coil when load impedance is high.

An induction wattmeter can be used for?

Last Answer : An induction wattmeter can be used for A.C. 

A dynamometer wattmeter can be used for?

Last Answer : A dynamometer wattmeter can be used for both D.C. and A.C.

The instrument for measurement of flow/ velocity is________. A. Bimetallic. C) Turbine meter. B. Manometer. D) Wattmeter

Description : The instrument for measurement of flow/ velocity is________. A. Bimetallic. C) Turbine meter. B. Manometer. D) Wattmeter

Last Answer : Turbine meter

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.

The power factor of a single phase load can be calculated if the instruments available are?

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

The power of a n-phase circuit can be measured by using a minimum of

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

A ground on a particular phase of a three-phase low voltage distribution system would be indicated by a _____________. A. high switchboard wattmeter reading B. low switchboard wattmeter reading C. dark or dim switchboard ground detecting light D. bright switchboard ground detecting light

Description : A ground on a particular phase of a three-phase low voltage distribution system would be indicated by a _____________. A. high switchboard wattmeter reading B. low switchboard wattmeter reading C. dark or dim switchboard ground detecting light D. bright switchboard ground detecting light

Last Answer : Answer: C

Which of the following instruments can be used for measurement of very high value resistances such as

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 

For measurement of inductance having high value, we should use?

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

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

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

A current carrying conductor making an electrical contact with a wiring metal conduit is indicated by a _____________. A. low switchboard wattmeter reading B. reading of 1.0 on the power factor meter C. high switchboard voltmeter reading D. totally darkened switchboard ground-detecting light

Description : A current carrying conductor making an electrical contact with a wiring metal conduit is indicated by a _____________. A. low switchboard wattmeter reading B. reading of 1.0 on the power factor meter C. high switchboard voltmeter reading D. totally darkened switchboard ground-detecting light

Last Answer : Answer: D

The true power indicated by a wattmeter depends on the current flow through the load, the magnitude of the potential across the load, and the _____________. A. power factor of the load B. angle of coil displacement C. inertia of the movable coil D. high resistance from the load

Description : The true power indicated by a wattmeter depends on the current flow through the load, the magnitude of the potential across the load, and the _____________. A. power factor of the load B. angle of coil displacement C. inertia of the movable coil D. high resistance from the load

Last Answer : Answer: A

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

The true power indicated by the pointer movement of a wattmeter depends on the current flow through the load, the magnitude of the potential across the load, and the ____________. A. power factor of the load B. angle of coil displacement C. inertia of the movable coil D. high resistance from the load

Description : The true power indicated by the pointer movement of a wattmeter depends on the current flow through the load, the magnitude of the potential across the load, and the ____________. A. power factor of the ... B. angle of coil displacement C. inertia of the movable coil D. high resistance from the load

Last Answer : Answer: A

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 portable hand-held and is very handy for determining the power consumption and power factor of individual motors and other inductive devices. a) Voltmeter and wattmeter. b) Wattmeter and power factor meter. c) Light meter and flash meter.

Description : A portable hand-held and is very handy for determining the power consumption and power factor of individual motors and other inductive devices. a) Voltmeter and wattmeter. b) Wattmeter and power factor meter. c) Light meter and flash meter.

Last Answer : Voltmeter and wattmeter.

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

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.   

A wattmeter is used to determine ____________. A. the power being consumed by electrical equipment B. partial circuit resistance C. current flowing in a circuit D. voltage existing between two points in a circuit

Description : A wattmeter is used to determine ____________. A. the power being consumed by electrical equipment B. partial circuit resistance C. current flowing in a circuit D. voltage existing between two points in a circuit

Last Answer : Answer: A