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

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

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The power delivered to a 3-phase load can be measured by the use of two wattmeters only

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 

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

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

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

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The potential coil of a single phase dynamometer wattmeter has 4840 Ohm resistance. Voltage across the load is

Description : The potential coil of a single phase dynamometer wattmeter has 4840 Ohm resistance. Voltage across the load is 220 V. With the potential coil connected on the load side, the meter indicates 100 W. Approximate percentage error due to wattmeter connection is (A) 11% (B) 9% (C) 1.1% (D) 3%

Last Answer : The potential coil of a single phase dynamometer wattmeter has 4840 Ohm resistance. Voltage across the load is 220 V. With the potential coil connected on the load side, the meter indicates 100 W. Approximate percentage error due to wattmeter connection is 11%

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.

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.

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

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

The reading of wattmeter in no load test of induction motor gives :

Description : The reading of wattmeter in no load test of induction motor gives : (A) Friction and windage loss (B) Copper losses on no load in the stator (C) Core losses (D) Sum of all losses

Last Answer : A

What electrical quantity is measured by a wattmeter?

Description : What electrical quantity is measured by a wattmeter?

Last Answer : Power

Which one of the following is the name of a device used to measure voltage without drawing ANY current from the circuit being measured? Is it: w) a wattmeter x) a galvanometer y) an ammeter z) a potentiometer

Description : Which one of the following is the name of a device used to measure voltage without drawing ANY current from the circuit being measured? Is it: w) a wattmeter x) a galvanometer y) an ammeter z) a potentiometer

Last Answer : ANSWER: Z -- A POTENTIOMETER

Electric current is measured using which of the following instrument ? (1) Ammeter (2) Voltmeter (3) Anemometer (4) Wattmeter

Description : Electric current is measured using which of the following instrument ? (1) Ammeter (2) Voltmeter (3) Anemometer (4) Wattmeter

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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. 

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

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.

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

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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

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 

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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.

Which of the following statement(s) is/are true concerning oxygen delivery? a. The amount of oxygen delivered to peripheral tissues is dependent upon the oxygen content in arterial blood and cardiac output b. Oxygen content is commonly measured in arterial blood c. The normal arterial-venous difference is 4 cc O2/dL d. Normal systemic oxygen delivery for a typical adult is approximately 1000 cc/min

Description : Which of the following statement(s) is/are true concerning oxygen delivery? a. The amount of oxygen delivered to peripheral tissues is dependent upon the oxygen content in arterial blood and cardiac ... O2/dL d. Normal systemic oxygen delivery for a typical adult is approximately 1000 cc/min

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Can I use 3 phase wattmeter in the single phase supply?

Description : Can I use 3 phase wattmeter in the single phase supply?

Last Answer : The three-wire, three-wattmeter connection has the advantages of indicating the power in each individual phase (not possible in the two-wattmeter connection) and phase to neutral voltages. In a single-phase system there are just two

Moving coil in dynamometer wattmeter connected a) In series with fixed coil b) Across supply c) In series with load d) Across load

Description : Moving coil in dynamometer wattmeter connected a) In series with fixed coil b) Across supply c) In series with load d) Across load

Last Answer : Ans: Across supply

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 :

In a household single phase induction type wattmeter, the meter can be reversed by: -

Description :  In a household single phase induction type wattmeter, the meter can be reversed by: - a) reversing the supply terminals b) reversing the load terminal c) opening the meter connection ... opening the meter and reversing the connection of both the potential coil terminals and current coil terminals

Last Answer :  In a household single phase induction type wattmeter, the meter can be reversed by: - opening the meter connection and reversing either the potential coil terminals or current coil terminals 

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.

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

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In a balanced 3 -phase 200 V circuit, the line current is 115.5 A. When the power is measured by two...

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

A three-phase star -connected load is operating at a power factor angle ϕ with ϕ being the angle between

Description : A three-phase star -connected load is operating at a power factor angle ϕ  with ϕ being the angle between

Last Answer : A three-phase star -connected load is operating at a power factor angle ϕ  with ϕ being the angle between Phase voltage and phase current

A three phase transmission line delivers a load of 5 MW at 0.8 power factor lagging. Resistance of each...

Description : A three phase transmission line delivers a load of 5 MW at 0.8 power factor lagging. Resistance of each conductor is 0.5 ohm / km. Receiving end voltage is 33 kV. If the line loss is not to exceed 10%, determine the length of the line.  (A) 7 km (B) 27.9 km (C) 56.8 km (D) 13.9 km

Last Answer : B

The average power delivered to an impedance 4 − j 3 Ω by a current 5Cos(100πt + 100) Ampere is

Description : The average power delivered to an impedance 4 − j 3 Ω by a current 5Cos(100πt + 100) Ampere is A) 44.2 W B) 50 W C) 62.5 W D) 125 W

Last Answer : The average power delivered to an impedance 4 − j 3 Ω by a current 5Cos(100πt + 100) Ampere is 50 W

State the principle of wattmeter.

Description : State the principle of wattmeter. 

Last Answer : Working Principle of Wattmeter: It consists of two stationary coils, called current coils and one moving coil, called voltage or potential coil. The current coils are connected such that they ... experiences a force and tends to move in the direction as per Fleming's left hand rule. 

Merits of two wattmeter method

Description : Merits of two wattmeter method

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State the effects of errors in dynamometer type wattmeter due to i) pc- inductance ii) pc- capacitance iii) mutual inductance iv) Connection.

Description : State the effects of errors in dynamometer type wattmeter due to i) pc- inductance ii) pc- capacitance iii) mutual inductance iv) Connection.

Last Answer : Errors in wattmeter:  i) pc - inductance: Pressure coil inductance causes wattmeter to read more power than actual .  ii) pc-capacitance: The wattmeter reads less power.  iii) ... iv) Connection: In uncompensated wattmeter , the reading of wattmeter includes the powerloss in coils. 

State any four errors that occur in dynamometer type wattmeter

Description : State any four errors that occur in dynamometer type wattmeter

Last Answer : Errors that occur in dynamometer type wattmeter: 1. Errors due to method of connection. 2. Error due to pressure coil inductance. 3. Error due to pressure coil Capacitance. 4. Error due to mutual ... Error due to eddy currents. 7. Temperature error. 8. Error due to vibration of moving system

Compare CC and PC of wattmeter on the basis of:- (i) Connection (ii) Status (iii) Number of turns (iv) Gauge of wire.

Description : Compare CC and PC of wattmeter on the basis of:- (i) Connection (ii) Status (iii) Number of turns (iv) Gauge of wire.

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With neat diagram explain constructional details of dynamometer type wattmeter.

Description : With neat diagram explain constructional details of dynamometer type wattmeter.

Last Answer : Working Principle of Wattmeter: It consists of two stationary coils, called current coils and one moving coil, called voltage or potential coil. The moving coil is mounted on the spindle, in the gap ... experiences a force and tends to move in the direction as per Fleming's left hand rule. 

State various types of errors in wattmeter.

Description : State various types of errors in wattmeter.

Last Answer : Types of Error in wattmeter: 1. Errors due to method of connection. 2. Error due to pressure coil inductance. 3. Error due to pressure coil Capacitance. 4. Error due to mutual inductance effect. 5. ... . Error due to eddy currents. 7. Temperature error. 8. Error due to vibration of moving system.

Explain construction & working of electrodynamometer type wattmeter.

Description : Explain construction & working of electrodynamometer type wattmeter.

Last Answer : Electrodynamometer Type Wattmeter:  Construction: It essentially consists of the fixed and moving coil. The fixed coil is split into two equal parts which are placed close together and parallel to each other. ... hence these instruments can be used for measurement of A.C. & D.C. power.

List the different errors in wattmeter & explain compensation for it.

Description : List the different errors in wattmeter & explain compensation for it.

Last Answer : Errors in Wattmeter Compensation method Error due to connection method To overcome this error, wattmeters are provided with additional compensating winding which is connected in series with ... due to friction The weight of moving system be reduced to minimum possible.

List one advantage and one disadvantage of one wattmeter method.

Description : List one advantage and one disadvantage of one wattmeter method. 

Last Answer : Advantages:  1) Only one wattmeter is used.  2) Less number of connections.  3) Cost required is less.  Disadvantages:  1) Used only for 3- Φ balanced load and not for ... be accessible for connecting the Pressure coil.  3) Delta connection must be opened to connect current coil. 

Consider the following statements with regard to induction type wattmeter : 1. Can be used on both ac and...

Description : Consider the following statements with regard to induction type wattmeter :  1. Can be used on both ac and dc systems.  2. Power consumption is relatively low.  3. It is accurate only at stated frequency and temperature.  Which ... /are correct ?  (a) 1 only (b) 2 only (c) 3 only (d) 1, 2 and 3

Last Answer : Consider the following statements with regard to induction type wattmeter :  1. Can be used on both ac and dc systems.  2. Power consumption is relatively low.  3. It is accurate only at stated frequency and temperature. ... correct ?  (a) 1 only (b) 2 only (c) 3 only (d) 1, 2 and 3

Which one is not a correct type of wattmeter?

Description : Which one is not a correct type of wattmeter? A. Dynamometer wattmeter B. Induction wattmeter C. Electrolyte wattmeter D. Electrostatic wattmeter 

Last Answer : Electrolyte wattmeter is not a correct type of wattmeter.

Use Voltmeter, ammeter, wattmeter to determine active, reactive and apparent power consumed in given R—C series circuit, draw phasor diagram.

Description : Use Voltmeter, ammeter, wattmeter to determine active, reactive and apparent power consumed in given R—C series circuit, draw phasor diagram.

Last Answer : Use Voltmeter, ammeter, wattmeter to determine active, reactive and apparent power consumed in given R-C series circuit, draw phasor diagram. Practical Significance In the industry environment ... autotransformer position to zero and switch OFF the supply. 8. Draw the phasor diagram.

Use Voltmeter, ammeter, wattmeter to determine active, reactive and apparent power consumed in given R-L series circuit, draw phasor diagram.

Description : Use Voltmeter, ammeter, wattmeter to determine active, reactive and apparent power consumed in given R-L series circuit, draw phasor diagram.

Last Answer : Practical Significance In the industry environment Electrical Engineering diploma graduate are expected to measure basic parameters like voltage, frequency, time period etc. for R-L series circuits. Therefore ... /varying L. 7. Draw the phasor diagram for each of reading for verification.