GATE Exam  >  GATE Questions  >  A 20-pole, 693-V, 50-Hz, 3-φ, Δ-connected syn... Start Learning for Free
A 20-pole, 693-V, 50-Hz, 3-φ, Δ-connected synchronous motor is operating at no-load with normal excitation. It has armature ressistance per phase of zero and synchronous reactance of 10 Ω. If rotor is retarded by 5º (mechanical) from its synchronous position, compute (i) rotor displacement in electrical degrees (ii) armature emf / phase (iii) armature current / phase (iv) power drawn by the motor (v) power developed by armature?
Most Upvoted Answer
A 20-pole, 693-V, 50-Hz, 3-φ, Δ-connected synchronous motor is operati...
Problem Statement

A 20-pole, 693-V, 50-Hz, 3-φ, Δ-connected synchronous motor is operating at no-load with normal excitation. It has armature resistance per phase of zero and synchronous reactance of 10 Ω. If rotor is retarded by 5º (mechanical) from its synchronous position, compute (i) rotor displacement in electrical degrees (ii) armature emf / phase (iii) armature current / phase (iv) power drawn by the motor (v) power developed by armature? Explain in detail.


Solution

Given data:


  • Number of poles (P) = 20

  • Line voltage (V) = 693V

  • Frequency (f) = 50Hz

  • Phase (φ) = 3

  • Connection = Δ-connected

  • Armature resistance (R) = 0Ω

  • Synchronous reactance (Xs) = 10Ω

  • Rotor displacement (δ) = 5º



Calculation of rotor displacement in electrical degrees

For a synchronous motor, the rotor displacement in electrical degrees is given by:

δ = (mechanical angle / 360) x P

where P is the number of poles.

Given that mechanical angle = 5º and P = 20,

δ = (5 / 360) x 20 = 0.278º


Calculation of armature emf / phase

For a synchronous motor, the armature emf per phase is given by:

Eph = V / √3

where V is the line voltage.

Given that V = 693V,

Eph = 693 / √3 = 399.77V


Calculation of armature current / phase

For a synchronous motor, the armature current per phase is given by:

Iph = Eph / Xs

where Xs is the synchronous reactance.

Given that Xs = 10Ω,

Iph = 399.77 / 10 = 39.977A


Calculation of power drawn by the motor

For a synchronous motor, the power drawn by the motor is given by:

P = 3 x Eph x Iph x sin(δ)

where δ is the rotor displacement in electrical degrees.

Given that δ = 0.278º,

P = 3 x 399.77 x 39.977 x sin(0.278º) = 3717.25W


Calculation of power developed by armature

For a synchronous motor, the power developed by the
Explore Courses for GATE exam
A 20-pole, 693-V, 50-Hz, 3-φ, Δ-connected synchronous motor is operating at no-load with normal excitation. It has armature ressistance per phase of zero and synchronous reactance of 10 Ω. If rotor is retarded by 5º (mechanical) from its synchronous position, compute (i) rotor displacement in electrical degrees (ii) armature emf / phase (iii) armature current / phase (iv) power drawn by the motor (v) power developed by armature?
Question Description
A 20-pole, 693-V, 50-Hz, 3-φ, Δ-connected synchronous motor is operating at no-load with normal excitation. It has armature ressistance per phase of zero and synchronous reactance of 10 Ω. If rotor is retarded by 5º (mechanical) from its synchronous position, compute (i) rotor displacement in electrical degrees (ii) armature emf / phase (iii) armature current / phase (iv) power drawn by the motor (v) power developed by armature? for GATE 2024 is part of GATE preparation. The Question and answers have been prepared according to the GATE exam syllabus. Information about A 20-pole, 693-V, 50-Hz, 3-φ, Δ-connected synchronous motor is operating at no-load with normal excitation. It has armature ressistance per phase of zero and synchronous reactance of 10 Ω. If rotor is retarded by 5º (mechanical) from its synchronous position, compute (i) rotor displacement in electrical degrees (ii) armature emf / phase (iii) armature current / phase (iv) power drawn by the motor (v) power developed by armature? covers all topics & solutions for GATE 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A 20-pole, 693-V, 50-Hz, 3-φ, Δ-connected synchronous motor is operating at no-load with normal excitation. It has armature ressistance per phase of zero and synchronous reactance of 10 Ω. If rotor is retarded by 5º (mechanical) from its synchronous position, compute (i) rotor displacement in electrical degrees (ii) armature emf / phase (iii) armature current / phase (iv) power drawn by the motor (v) power developed by armature?.
Solutions for A 20-pole, 693-V, 50-Hz, 3-φ, Δ-connected synchronous motor is operating at no-load with normal excitation. It has armature ressistance per phase of zero and synchronous reactance of 10 Ω. If rotor is retarded by 5º (mechanical) from its synchronous position, compute (i) rotor displacement in electrical degrees (ii) armature emf / phase (iii) armature current / phase (iv) power drawn by the motor (v) power developed by armature? in English & in Hindi are available as part of our courses for GATE. Download more important topics, notes, lectures and mock test series for GATE Exam by signing up for free.
Here you can find the meaning of A 20-pole, 693-V, 50-Hz, 3-φ, Δ-connected synchronous motor is operating at no-load with normal excitation. It has armature ressistance per phase of zero and synchronous reactance of 10 Ω. If rotor is retarded by 5º (mechanical) from its synchronous position, compute (i) rotor displacement in electrical degrees (ii) armature emf / phase (iii) armature current / phase (iv) power drawn by the motor (v) power developed by armature? defined & explained in the simplest way possible. Besides giving the explanation of A 20-pole, 693-V, 50-Hz, 3-φ, Δ-connected synchronous motor is operating at no-load with normal excitation. It has armature ressistance per phase of zero and synchronous reactance of 10 Ω. If rotor is retarded by 5º (mechanical) from its synchronous position, compute (i) rotor displacement in electrical degrees (ii) armature emf / phase (iii) armature current / phase (iv) power drawn by the motor (v) power developed by armature?, a detailed solution for A 20-pole, 693-V, 50-Hz, 3-φ, Δ-connected synchronous motor is operating at no-load with normal excitation. It has armature ressistance per phase of zero and synchronous reactance of 10 Ω. If rotor is retarded by 5º (mechanical) from its synchronous position, compute (i) rotor displacement in electrical degrees (ii) armature emf / phase (iii) armature current / phase (iv) power drawn by the motor (v) power developed by armature? has been provided alongside types of A 20-pole, 693-V, 50-Hz, 3-φ, Δ-connected synchronous motor is operating at no-load with normal excitation. It has armature ressistance per phase of zero and synchronous reactance of 10 Ω. If rotor is retarded by 5º (mechanical) from its synchronous position, compute (i) rotor displacement in electrical degrees (ii) armature emf / phase (iii) armature current / phase (iv) power drawn by the motor (v) power developed by armature? theory, EduRev gives you an ample number of questions to practice A 20-pole, 693-V, 50-Hz, 3-φ, Δ-connected synchronous motor is operating at no-load with normal excitation. It has armature ressistance per phase of zero and synchronous reactance of 10 Ω. If rotor is retarded by 5º (mechanical) from its synchronous position, compute (i) rotor displacement in electrical degrees (ii) armature emf / phase (iii) armature current / phase (iv) power drawn by the motor (v) power developed by armature? tests, examples and also practice GATE tests.
Explore Courses for GATE exam
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
10M+ students study on EduRev