Electrical Engineering
GATE EE topic:electrical-machines PYQs
Build your understanding with focused practice from past exam papers.
Questions 671–680 of 715. Imported answers require independent review unless marked reviewed.
Question 43
Open questionEE-2NAT2 marksNeeds review
A star-connected, 12.5kW, 208 V (line), 3-phase, 60 Hz squirrel cage induction motor has following equivalent circuit parameters per phase referred to the stator: R₁=0.3Ω, R₂′=0.3Ω, X₁=0.4Ω, X₂′=0.4Ω. Neglect shunt branch in the equivalent circuit. The starting current (in Ampere) for this motor when connected to an 80 V (line), 20 Hz, 3-phase AC source is __________.
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Open questionEENAT2 marksNeeds review
The magnitude of magnetic flux density (
) in micro Teslas (
), at the center of a loop of wire wound as a regular hexagon of side length 1 m carrying a current (
A), and placed in vacuum as shown in the figure is ________. (Give the answer up to two decimal places.)
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Open questionEE-2NAT2 marksNeeds review
A 25 kVA, 400 V, Δ-connected, 3-phase, cylindrical rotor synchronous generator requires a field current of 5 A to maintain the rated armature current under short-circuit condition. For the same field current, the open-circuit voltage is 360 V. Neglecting the armature resistance and magnetic saturation, its voltage regulation (in % with respect to terminal voltage), when the generator delivers the rated load at 0.8 pf leading, at rated terminal voltage is ____________.
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 45
Open questionEENAT2 marksNeeds review
A 375 W, 230 V, 50 Hz, capacitor start single-phase induction motor has the following constants for the main and auxiliary windings (at start):
(main winding),
(auxiliary winding). Neglecting the magnetizing branch, the value of the capacitance (in
F) to be added in series with the auxiliary winding to obtain maximum torque at starting 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 45
Open questionEE-2NAT2 marksNeeds review
If the primary line voltage rating is 3.3 kV (Y side) of a 25 kVA, Y-Δ transformer (the per phase turns ratio is 5:1), then the line current rating of the secondary side (in Ampere) is _____.
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 46
Open questionEENAT2 marksNeeds review
Two parallel connected, three-phase, 50Hz, 11 kV, star-connected synchronous machines A and B, are operating as synchronous condensers. They together supply 50 MVAR to a 11 kV grid. Current supplied by both the machines are equal. Synchronous reactances of machine A and machine B are 1Ω and 3Ω, respectively. Assuming the magnetic circuit to be linear, the ratio of excitation current of machine A to that of machine B is ________. (Give the answer up to two decimal places.)
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 46
Open questionEE-2NAT2 marksNeeds review
Consider the system described by the following state space representation
If
is a unit step input and
the value of output
at
sec (rounded off to three decimal places) 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 47
Open questionEENAT2 marksNeeds review
A 220 V DC series motor runs drawing a current of 30 A from the supply. Armature and field circuit resistances are 0.4 Ω and 0.1 Ω, respectively. The load torque varies as the square of the speed. The flux in the motor may be taken as being proportional to the armature current. To reduce the speed of the motor by 50%, the resistance in ohms that should be added in series with the armature is ________. (Give the answer up to two decimal places.)
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Open questionEE-2NAT2 marksNeeds review
A 10 ½ digit timer counter possesses a base clock of frequency 100 MHz. When measuring a particular input, the reading obtained is the same in (i) Frequency mode of operation with a gating time of one second and (ii) Period mode of operation (in the x 10 ns scale). The frequency of the unknown input (reading obtained) in Hz is _____.
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 48
Open questionEENAT2 marksNeeds review
A three-phase, three winding
(1.1 kV/6.6 kV/400 V) transformer is energized from AC mains at the 1.1 kV side. It supplies 900 kVA load at 0.8 power factor lag from the 6.6 kV winding and 300 kVA load at 0.6 power factor lag from the 400 V winding. The RMS line current in ampere drawn by the 1.1 kV winding from the mains is ________. (Give the answer up to one decimal place.)Log in to check the answer
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