Electrical Engineering · Question Bank

3P AC Circuits

53 of 71 questions match · page 2 of 3. Answer in your head first, then check the solution.

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TypeAll 53Problem solving 23Objective 30
DifficultyAll 71Easy 53Medium 17Hard 1
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#21📜 EE Pre-Board March 2016📘 PowerhouseEasy
A delta 3Φ, 4-wire secondary 230/115 V would have a high-leg to neutral voltage of ________.
A208 V
B230 V
C277 V
D199 V
#22📜 EE Pre-Board March 2017📘 PowerhouseEasy
Convert the delta connected impedance of \(12\angle 36^\circ\) Ω to a balanced wye connected impedance.
A\(3\angle 36^\circ\) Ω
B\(6\angle 36^\circ\) Ω
C\(4\angle 36^\circ\) Ω
D\(12\angle 36^\circ\) Ω
#23📜 EE Pre-Board March 2017📘 PowerhouseEasy
The type of ac distribution system commonly used to supply both light and power is the
Aopen delta system
Bthree phase delta system
Cthree phase wye system with neutral wire
Dthree phase wye system without neutral wire
#24📜 EE Pre-Board March 2017📘 PowerhouseEasy
In a balanced 3-phase voltage source with phase sequence abc, the phase A voltage is \(127\angle 0^\circ\) volts. Find the phase C voltage.
A\(127\angle -240^\circ\) V
B\(220\angle -150^\circ\) V
C\(220\angle -120^\circ\) V
D\(127\angle -60^\circ\) V
#25📜 EE Pre-Board March 2017📘 PowerhouseEasy
In a three-phase system, when the loads are perfectly balanced, the neutral current is
Azero
Bone-third of maximum
Ctwo-thirds of maximum
Dat maximum
#26📜 EE Pre-Board March 2017📘 PowerhouseEasy
A balanced delta connected load draws 10 A of line current and 3 KW at 220 v. Determine the value of resistance of each phase of the load.
A38.1 Ω
B30 Ω
C23.5 Ω
D33.3 Ω
#27📜 EE Pre-Board August 2017📘 PowerhouseEasy
A 440 V, three-phase source supplies a wye connected 10 kVA load at 0.8 lagging power factor and a delta-connected 10 kVA unity power factor load. Calculate the total apparent power input to the two loads.
A20 kVA
B18 kVA
C14.14 kVA
D18.97 kVA
#28📜 EE Pre-Board August 2017📘 PowerhouseEasy
A balanced wye-connected load with a resistance of 8 ohms/phase and no reactance is supplied by a 240 V, 3-phase source. Find the real power of the load in watts.
A2,400
B7,200
C21,600
D4,157
#29📜 EE Pre-Board August 2017📘 PowerhouseEasy
An abc phase sequence three-phase voltage source connected in a balanced wye has a line voltage of \(V_{ab} = 208\angle 0^\circ\) V rms. Determine the phase voltage \(V_{bn}\).
A\(120\angle -30^\circ\) V
B\(208\angle -120^\circ\) V
C\(120\angle -150^\circ\) V
D\(120\angle 90^\circ\) V
#30📜 EE Pre-Board August 2017📘 PowerhouseEasy
A balanced delta connected load of 4 − j3 Ω per phase is fed by a 380 V, 3-phase system. Find the reactive power.
A52 kVAR
B17.3 kVAR
C69.3 kVAR
D30 kVAR
#31📜 EE Pre-Board March 2018📘 PowerhouseEasy
In a delta connected circuit of three equal resistors, when one resistor is open, the power will be
A0
Bincreased by a factor of 3
Cdecreased by a factor of 3
Dremain unchanged
#32📜 EE Pre-Board March 2018📘 PowerhouseEasy
For a 3-phase load balanced condition, each phase has the same value of _
Aimpedance
Bresistance
Cpower factor
Dall of these
#33📜 EE Pre-Board March 2018📘 PowerhouseEasy
Three 100 μF capacitors are connected in delta to a 500-volt, three-phase, 50 Hz supply. Find the line current.
A15.71 A
B27.21 A
C31.83 A
D8.66 A
#34📜 EE Pre-Board March 2018📘 PowerhouseEasy
In a star connected system, the current flowing through the line is
AGreater than the phase current
BEqual to the phase current
CLesser than the phase current
DNone of these
#35📜 EE Pre-Board March 2018📘 PowerhouseEasy
A balanced delta connected load consists of \(20\angle 25^\circ\) Ω impedances. The 60 Hz line voltage is 208 V. What is the line current?
A6A
B10.4A
C12A
D18A
#36📜 EE Pre-Board March 2018📘 PowerhouseEasy
In a certain Y-Y system, the source phase currents each have a magnitude of 9 A. The magnitude of each load current for a balanced load condition is
A12 A
B3 A
C9 A
D27 A
#37📜 EE Pre-Board March 2018📘 PowerhouseEasy
In a three-phase system, the voltages are separated by
A90°
B45°
C120°
D180°
#38📜 EE Pre-Board March 2018📘 PowerhouseEasy
In a three-phase system, when the loads are perfectly balanced, the neutral current is
Aone-third of maximum
Bzero
Ctwo-thirds of maximum
Dat maximum
#39📜 EE Pre-Board March 2018📘 PowerhouseEasy
A 230 v, 3-phase source supplies a balanced delta connected load with impedance of 8-j6 ohms per phase. Calculate the line current in amperes.
A33.1
B39.8
C26.5
D29.3
#40📜 EE Pre-Board March 2018📘 PowerhouseEasy
In a balanced 3-phase wye-connected voltage source with phase sequence abc, \(V_{ab} = 230\angle 10^\circ\) V. Find the phase voltage \(V_{cn}\).
A\(230\angle -230^\circ\) V
B\(132.8\angle -80^\circ\) V
C\(132.8\angle -140^\circ\) V
D\(132.8\angle -260^\circ\) V

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