Find real questions from previous competitive exam papers with answers and solutions.
Leave the keyword blank to browse saved questions for your selected exam, newest papers first. Add a keyword, year or topic to narrow the results.
Browse complete papersWhat happens to the speed of a DC motor if the applied voltage is increased?
It stays the same
It stops completely
It decreases
It increases
Correct answer
It stays the same
In a DC motor, what is the name of the stationary part that houses the field windings?
Armature
Rotor
Commutator
Stator
Correct answer
Armature
Which of the following describes the operation of a single-phase induction motor?
It runs at a speed faster than the synchronous speed
It can start on its own without any auxiliary windings
It requires two AC sources to start and run
It is not self-starting and requires a starting mechanism like an auxiliary winding.
Correct answer
It runs at a speed faster than the synchronous speed
What is the key component of an AC generator (alternator) that is used to create the main magnetic field?
The armature winding
The commutator
The field winding on the rotor
The yoke
Correct answer
The armature winding
The rotating magnetic field in a three-phase AC machine rotates at a speed known as the:
Torque speed
Rotor speed
Synchronous speed
Slip speed
Correct answer
Torque speed
A 6-pole, three-phase induction motor is connected to a 50 Hz supply. The motor runs at 960 rpm under full load. What is the slip of the motor?
6%
3%
5%
4%
Correct answer
6%
A three-phase, 400 V synchronous motor is operating at a leading power factor of 0. 8 while drawing a line current of 20 A. What is the reactive power drawn by the motor?
Correct answer
A series circuit consists of a 24 V battery, a 4 \(\Omega\) resistor, and a 2 \(\Omega\) resistor. An ammeter with an internal resistance of 0. 5 \(\Omega\) is used to measure the current. What is the reading on the ammeter?
5 A
6 A
Correct answer
An AC circuit has a true power of 500 W and an apparent power of 625 VA. What is the power factor of the circuit?
1.25
1
Correct answer
1.25
A power factor of \(1\) (unity) indicates that the circuit is primarily:
Capacitive
Reactive
Resistive
Inductive
Correct answer
Capacitive