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

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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

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

## Related questions

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

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?

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

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

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

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

In the measurement of three phase power by two wattmeter method, if the two wattmeter readings are equal then power factor of the circuit is  (A) 0.8 lag (B) Unity (C) 0.8 lead (D) Zero

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

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

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

Two wattmeter method can be used in a three phase system excited with balanced three phase supply  A) To measure real power and power factor in a balanced load B) To measure reactive power in a balanced load C) To measure real power in an unbalanced load D) All of the above

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

Measurement of power by voltmeter and ammeter method in a circuit resulted in calculated maximum errors of ±1 % and ± 2 %, respectively. The likely error in calculated power is (A) ± 3 % (B) ± 0.022 % (C) ± 1.5 % (D) ± 0.22 %

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

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

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

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

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

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

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 and reversing either the potential coil terminals or current coil terminals d) opening the meter and reversing the connection of both the potential coil terminals and current coil terminals

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

If a dynamometer wattmeter is connected in an ac circuit, the power indicated by the wattmeter will be (a) volt-ampere product (b) average power (c) peak power (d) instantaneous power

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

. If the peak transmitted power in a radar system is increased by a factor of 16, the maximum range will be increased by a factor of : (A) 2 (B) 4 (C) 8 (D) 16

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 of the impedance of the voltage coil circuit  A) (i) is true but (ii) is false B) (i) is false but (ii) is true C) Both (i) and (ii) are true D) Both (i) and (ii) are false

The voltage profile of a n-bus power system can be improved by controlling the (A) load angles (B) active power flows (C) reactive power flows (D) complex power flows

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 ?

For a balanced three phase star connected load for which line voltage is 230V and per phase resistance and reactance is 6 Ohm and 8 Ohm respectively. Calculate: 1) phase voltage 2) line current 3) power factor 4) total power absorbed

Which method can be used for absolute measurement of resistance? A. Ohm's law method B. Wheatstone bridge method C. Both A & B D. None of these.

The resolving power of a spectrometer consisting of collimator, a grating and a telescope can be increased by (A) increasing the angular magnification of the telescope (B) increasing the period of the grating (C) decreasing the period of the grating (D) decreasing the slit-width of the collimator

The steady state stability of the power system can be improved by (A) using machines of high impedance (B) connecting transmission lines in series. (C) connecting lines in parallel. (D) reducing, the excitation of the machines.

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

State two advantages and two disadvantages of photoelectric pick-up speed measurement method.

Name two methods for measurement of low, medium and high resistance. Give one advantage and one limitation of V- I method.

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