Test: Electrical & Electronic Measurements- 3 - Electrical Engineering (EE) MCQ

Calculate the magnitude of line current in the circuit shown in figure.

In the balanced three phase circuit shown in figure, the current coil of the wattmeter is connected in line aA, and the potential coil of the wattmeter us connected across lines b and c. The phase sequence is positive and the load power factor is 0.8 lag. The wattmeter reading will be

A 5A, 110V electrodynamic type wattmeter has a scale having 110 divisions. Its pressure coil is fed by a voltage of  [110√2cos(314t) + √2sin(942t)]  V and is current coil carries a current of [5√2cos(314t + 60) + 2√2sin(628t + 90) + √2cos(642t + 90)] A. The needle of the wattmeter will move to

The constant of the shunt to extend the range 0-10 A moving iron ammeter to 0-100 A, the instrument constant are R = 0.18 Ω and L = 180 μH. If the shunt is made non-inductive and the combination is correct on dc. Find the full-scale error (in percentage) at 50 Hz.

The reading of a dynamometer – type wattmeter with pressure coil phase angle of 2° is 700 watts, when it is used to measure power of a single phase inductive load supplied by 240 V single phase ac. source. when the wattmeter is replaced by a second wattmeter with a phase angle of 1° for the pressure coil circuit, a reading of 620 watts is obtained. Assuming all errors of the wattmeter, except those due to pressure coil inductance are neglected. The actual power is ____________(in W)

A wattmeter reads 5.54 kW when its current coil is connected in the red phase and its voltage coil is connected between the neutral and red phase of a symmetrical three phase system supplying a balanced load of 30 A at 400 V. What will be the reading of the instrument if the current coil remains unchanged and voltage coil be connected between blue and yellow phases. The phase sequence is RYB.

The balanced three phase load shown in figure is fed form a balanced, positive sequence, there phase Y-connected source. The impedance of the line connecting the source to the load is negligible the line to neutral voltage of the source is 7200 V. Find the reading of the wattmeter in kW.