A 3-phase balanced load which has a power factor of 0.707 is connected to balanced supply. The power consumed by the load is 5 kW. The power is measured by the two wattmeter method. The readings of the two wattmeters are
The coils of a wattmeter have resistances 0.01$\mathrm{\Omega}$ and 1000$\mathrm{\Omega}$; their inductances may be neglected. The wattmeter is connected as shown in the figure, to measure the power consumed by a load, which draws 25A at power factor 0.8. The voltage across the load terminals is 30V. The percentage error on the wattmeter reading is _________.
Power consumed by a balanced 3-phase, 3-wire load is measured by the two wattmeter method. The first wattmeter reads twice that of the second. Then the load impedance angle in radians is
While measuring power of a three-phase balanced load by the two-wattmeter method, the readings are 100 W and 250 W. The power factor of the load is _________.
An LPF wattmeter of power factor 0.2 is having three voltage settings 300 V, 150 V and 75 V, and two current settings 5 A and 10 A. The full scale reading is 150. If the wattmeter is used with 150 V voltage setting and 10 A current setting, the multiplying factor of the wattmeter is _________.
For the circuit shown in the figure, the voltage and current expressions are
$v\left(t\right)={E}_{1}\mathrm{sin}\left(\omega t\right)+{E}_{3}\mathrm{sin}\left(3\omega t\right)$ and $i\left(t\right)={I}_{1}\mathrm{sin}\left(\omega t-{\Phi}_{1}\right)+{I}_{3}\mathrm{sin}\left(3\omega t-{\Phi}_{3}\right)+{I}_{5}\mathrm{sin}\left(5\omega t\right)$
The average power measured by the Wattmeter is
Consider the following statement (i) 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 wattmeter is connected as shown in the figure. The wattmeter reads
The pressure coil of a dynamometer type wattmeter is
The figure shows a three-phase delta connected load supplied from a 400V, 50 Hz, 3-phase balanced source. The pressure coil (PC) and current coil (CC) of a wattmeter are connected to the load as shown, with the coil polarities suitably selected to ensure a positive deflection. The wattmeter reading will be