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

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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

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

## Related questions

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

The power in a 3-phase load is measured by two watt meters. If one watt meter reads zero, then the load power factor is (A) Zero (B) 0.5 (C ) 0.866 (D) unity

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

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-wire balanced load  4. Balanced source with 3-phase 4-wire unbalanced load  5. unbalanced and unbalanced source    (a) 1 only (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 of the wattmeters are 4 kW and 2 kW respectively, the later is being taken after reversing the connections of current coil. the power factor and reactive power of the load is A) 0.2 & 6 kVAR B) 0.2 & 6 √3 kVAR C) 0.32 & 2 kVAR D) 0.32 & 2 √3 kVAR

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

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

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 ?

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?

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

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

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

In the equivalent circuit of a 3-phase induction motor, the mechanical load on the motor can be represented by a resistance of value (1) R2 (2) R2/S (3) R2(1-S)/S (4) (R2/S)+1

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

Which of the following instruments can be used to measure AC current only? (a) Permanent Magnet Type ammeter(b) Induction type ammeter (c) Moving iron voltmeter(d) Moving iron ammeter

Two 3-phase, Y-connected alternators are to be paralleled to a set of common busbars. The armature has a per phase synchronous reactance of 1.7 Ohm and negligible armature resistance. The line voltage of the first machine is adjusted to 3300 V and that of the second machine is adjusted to 3200 V. The machine voltages are in phase at the ... are paralleled. Under this condition, the synchronizing current per phase will be  (A) 16.98 A (B) 29.41 A (C) 33.96 A (D) 58.82 A

The power in a 3phase circuit is measured with the help of 2 wattmeters. The reading of one of wattmeters is positive and that of the others is negative. The magnitude of readings is different. It can be concluded that the power factor of the circuit is  (A) Unity (B) 2 (lagging) (C) 5 (lagging) (D) Less than 0.5 (lagging)

The efficiency of two identical transformers under load conditions can be determined by?

In a 3 -phase alternator, if there is only magnetizing armature reaction, the load is :  (A) capacitive (B) inductive (C) resistive (D) inductive and resistive

The fall in speed of a dc generator due to increase in load can be corrected by  (1) cooling the armature.. (2) increasing the excitation. (3) reducing the load voltage. (4) increasing the input to the prime mover

The self inductance of a coil can be measured using (A) Wien’s Bridge (B) Schering Bridge (C) Anderson’s Bridge (D) Wheatstone Bridge

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

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 unit positive sequence impedance of the line based on 100 MVA and 11 kV is j0.2. The line to line voltage at the ... load to increase the line-to-line voltage at the load terminals to 11 kV is  (A) 100 MVAR (B) 10.1 MVAR (C) -100 MVAR (D) -10.1 MVAR

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

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

A three phase transformer can be used in emergency at reduced rating of 58% to deliver three phase power when it is connected (a) in star-delta (b) delta-star (c) star-star (d) delta-delta

In 3-phase induction motors, speeds higher than synchronous speed can be had by  (1) line voltage control (2) rotor slip power control (3) rotor resistance control [4) frequency control

Which parameter or quantity may be measured by use of Maxwell's Bridge ? (A) Resistance (B) Capacitance (C) Inductance (D) Frequency

A 3 -phase, fully controlled, converter is feeding power into a DC load at a constant current of 150 A, the rms value of the current flowing through each thyristor of the converter is

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