Electrical Engineering
GATE EE Electrical Machines PYQs
Build your understanding with focused practice from past exam papers.
Questions 61–70 of 79. Imported answers require independent review unless marked reviewed.
Question 24
Open questionEENAT1 markNeeds review
A separately excited dc motor has an armature resistance
. The field excitation is kept constant. At an armature voltage of 100 V, the motor produces a torque of 500 Nm at zero speed. Neglecting all mechanical losses, the no-load speed of the motor (in radians/s) for an armature voltage of 150 V is ____ (up to 2 decimal places).Log in to check the answer
You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 30
Open questionEEMCQ2 marksNeeds review
The per-unit power output of a salient-pole generator which is connected to an infinite bus, is given by the expression,
, where
is the load angle. Newton-Raphson method is used to calculate the value of
for
pu. If the initial guess is 30°, then its value (in degree) at the end of the first iteration isYour answerChoose one option.
Log in to check the answer
You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 51
Open questionEENAT2 marksNeeds review
A 3-phase 900 kVA,
(
/Y), 50 Hz transformer has primary (high voltage side) resistance per phase of 0.3
and secondary (low voltage side) resistance per phase of 0.02
. Iron loss of the transformer is 10 kW. The full load % efficiency of the transformer operated at unity power factor is ________ (up to 2 decimal places).Log in to check the answer
You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 52
Open questionEENAT2 marksNeeds review
A 200 V DC series motor, when operating from rated voltage while driving a certain load, draws 10 A current and runs at 1000 r.p.m. The total series resistance is 1
. The magnetic circuit is assumed to be linear. At the same supply voltage, the load torque is increased by 44%. The speed of the motor in r.p.m. (rounded to the nearest integer) is ______.Log in to check the answer
You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 54
Open questionEENAT2 marksNeeds review
The equivalent circuit of a single phase induction motor is shown in the figure, where the parameters are
,
and
is the slip. At no-load, the motor speed can be approximated to be the synchronous speed. The no-load lagging power factor of the motor is _________ (up to 3 decimal places). 
Log in to check the answer
You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 5
Open questionEE-2MCQ1 markNeeds review
If a synchronous motor is running at a leading power factor, its excitation induced voltage (
) isYour answerChoose one option.
Log in to check the answer
You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 8
Open questionEEMCQ1 markNeeds review
A 4 pole induction machine is working as an induction generator. The generator supply frequency is 60 Hz. The rotor current frequency is 5 Hz. The mechanical speed of the rotor in RPM is
Your answerChoose one option.
Log in to check the answer
You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 14
Open questionEE-2MCQ1 markNeeds review
A 3-phase, 4-pole, 400 V, 50 Hz squirrel-cage induction motor is operating at a slip of 0.02. The speed of the rotor flux in mechanical rad/sec, sensed by a stationary observer, is closest to
Your answerChoose one option.
Log in to check the answer
You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 20
Open questionEENAT1 markNeeds review
A three-phase, 50Hz, star-connected cylindrical-rotor synchronous machine is running as a motor. The machine is operated from a 6.6 kV grid and draws current at unity power factor (UPF). The synchronous reactance of the motor is 30 Ω per phase. The load angle is 30°. The power delivered to the motor in kW is _____. (Give the answer up to one decimal place).
Log in to check the answer
You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 33
Open questionEE-2MCQ2 marksNeeds review
A 220 V, 10 kW, 900 rpm separately excited DC motor has an armature resistance
. When the motor operates at rated speed and with rated terminal voltage, the electromagnetic torque developed by the motor is 70 Nm. Neglecting the rotational loss of the machine, the current drawn by the motor from the 220 V supply isYour answerChoose one option.
Log in to check the answer
You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answer