Electrical Engineering (EE) Exam  >  Electrical Engineering (EE) Questions  >  A 3-phase squirrel cage induction motor has m... Start Learning for Free
A 3-phase squirrel cage induction motor has maximum torque equal to twice the full-load torque. The per phase rotor resistance and per phase standstill reactance referred to stator are 0.2 Ω and 2 Ω respectively (Stator impedance is neglected). What is the ratio of motor starting toque to its full-load torque, if the motor is started by direct-on-line starter?
  • a)
    0.396    
  • b)
    0.194
  • c)
    0.198    
  • d)
    0.400
Correct answer is option 'A'. Can you explain this answer?
Most Upvoted Answer
A 3-phase squirrel cage induction motor has maximum torque equal to tw...
The torque-speed characteristic of a squirrel cage induction motor is given by the equation:

T = (3V^2 * R2) / (s * X2)

Where:
T = Torque (Nm)
V = Line voltage (V)
R2 = Rotor resistance per phase referred to stator (ohm)
s = Slip (ratio of difference between synchronous speed and rotor speed to synchronous speed)
X2 = Rotor reactance per phase referred to stator (ohm)

Given that the maximum torque is twice the full-load torque, we can express this as:

2 * T_fullload = (3V^2 * R2) / (s * X2)

We also know that the slip at full load (s_fullload) is given by:

s_fullload = (Ns - N) / Ns

Where:
Ns = Synchronous speed (rpm)
N = Rotor speed (rpm)

Since the synchronous speed is given by:

Ns = (120 * f) / P

Where:
f = Frequency (Hz)
P = Number of poles

Let's assume the motor has a full-load speed of N_fullload (rpm). Then, the synchronous speed can be calculated using the slip equation:

s_fullload = (Ns - N_fullload) / Ns

Solving for Ns:

Ns = N_fullload / (1 - s_fullload)

Now, we can substitute this into the equation for slip:

s_fullload = (Ns - N_fullload) / Ns
s_fullload = (N_fullload / (1 - s_fullload) - N_fullload) / (N_fullload / (1 - s_fullload))
s_fullload = 1 - (1 - s_fullload) / (1 - s_fullload)
s_fullload = 1 - 1
s_fullload = 0

Since the slip at full load is 0, the rotor speed at full load is equal to the synchronous speed:

N_fullload = Ns

Now, let's substitute this into the equation for torque:

2 * T_fullload = (3V^2 * R2) / (0 * X2)
2 * T_fullload = 0

This equation implies that the maximum torque cannot be twice the full-load torque for a 3-phase squirrel cage induction motor. There may be an error in the given information.
Free Test
Community Answer
A 3-phase squirrel cage induction motor has maximum torque equal to tw...


From equations (i) and (ii), we have
Explore Courses for Electrical Engineering (EE) exam

Similar Electrical Engineering (EE) Doubts

Top Courses for Electrical Engineering (EE)

A 3-phase squirrel cage induction motor has maximum torque equal to twice the full-load torque. The per phase rotor resistance and per phase standstill reactance referred to stator are 0.2 Ω and 2 Ω respectively (Stator impedance is neglected). What is the ratio of motor starting toque to its full-load torque, if the motor is started by direct-on-line starter?a)0.396 b)0.194c)0.198 d)0.400Correct answer is option 'A'. Can you explain this answer?
Question Description
A 3-phase squirrel cage induction motor has maximum torque equal to twice the full-load torque. The per phase rotor resistance and per phase standstill reactance referred to stator are 0.2 Ω and 2 Ω respectively (Stator impedance is neglected). What is the ratio of motor starting toque to its full-load torque, if the motor is started by direct-on-line starter?a)0.396 b)0.194c)0.198 d)0.400Correct answer is option 'A'. Can you explain this answer? for Electrical Engineering (EE) 2024 is part of Electrical Engineering (EE) preparation. The Question and answers have been prepared according to the Electrical Engineering (EE) exam syllabus. Information about A 3-phase squirrel cage induction motor has maximum torque equal to twice the full-load torque. The per phase rotor resistance and per phase standstill reactance referred to stator are 0.2 Ω and 2 Ω respectively (Stator impedance is neglected). What is the ratio of motor starting toque to its full-load torque, if the motor is started by direct-on-line starter?a)0.396 b)0.194c)0.198 d)0.400Correct answer is option 'A'. Can you explain this answer? covers all topics & solutions for Electrical Engineering (EE) 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for A 3-phase squirrel cage induction motor has maximum torque equal to twice the full-load torque. The per phase rotor resistance and per phase standstill reactance referred to stator are 0.2 Ω and 2 Ω respectively (Stator impedance is neglected). What is the ratio of motor starting toque to its full-load torque, if the motor is started by direct-on-line starter?a)0.396 b)0.194c)0.198 d)0.400Correct answer is option 'A'. Can you explain this answer?.
Solutions for A 3-phase squirrel cage induction motor has maximum torque equal to twice the full-load torque. The per phase rotor resistance and per phase standstill reactance referred to stator are 0.2 Ω and 2 Ω respectively (Stator impedance is neglected). What is the ratio of motor starting toque to its full-load torque, if the motor is started by direct-on-line starter?a)0.396 b)0.194c)0.198 d)0.400Correct answer is option 'A'. Can you explain this answer? in English & in Hindi are available as part of our courses for Electrical Engineering (EE). Download more important topics, notes, lectures and mock test series for Electrical Engineering (EE) Exam by signing up for free.
Here you can find the meaning of A 3-phase squirrel cage induction motor has maximum torque equal to twice the full-load torque. The per phase rotor resistance and per phase standstill reactance referred to stator are 0.2 Ω and 2 Ω respectively (Stator impedance is neglected). What is the ratio of motor starting toque to its full-load torque, if the motor is started by direct-on-line starter?a)0.396 b)0.194c)0.198 d)0.400Correct answer is option 'A'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of A 3-phase squirrel cage induction motor has maximum torque equal to twice the full-load torque. The per phase rotor resistance and per phase standstill reactance referred to stator are 0.2 Ω and 2 Ω respectively (Stator impedance is neglected). What is the ratio of motor starting toque to its full-load torque, if the motor is started by direct-on-line starter?a)0.396 b)0.194c)0.198 d)0.400Correct answer is option 'A'. Can you explain this answer?, a detailed solution for A 3-phase squirrel cage induction motor has maximum torque equal to twice the full-load torque. The per phase rotor resistance and per phase standstill reactance referred to stator are 0.2 Ω and 2 Ω respectively (Stator impedance is neglected). What is the ratio of motor starting toque to its full-load torque, if the motor is started by direct-on-line starter?a)0.396 b)0.194c)0.198 d)0.400Correct answer is option 'A'. Can you explain this answer? has been provided alongside types of A 3-phase squirrel cage induction motor has maximum torque equal to twice the full-load torque. The per phase rotor resistance and per phase standstill reactance referred to stator are 0.2 Ω and 2 Ω respectively (Stator impedance is neglected). What is the ratio of motor starting toque to its full-load torque, if the motor is started by direct-on-line starter?a)0.396 b)0.194c)0.198 d)0.400Correct answer is option 'A'. Can you explain this answer? theory, EduRev gives you an ample number of questions to practice A 3-phase squirrel cage induction motor has maximum torque equal to twice the full-load torque. The per phase rotor resistance and per phase standstill reactance referred to stator are 0.2 Ω and 2 Ω respectively (Stator impedance is neglected). What is the ratio of motor starting toque to its full-load torque, if the motor is started by direct-on-line starter?a)0.396 b)0.194c)0.198 d)0.400Correct answer is option 'A'. Can you explain this answer? tests, examples and also practice Electrical Engineering (EE) tests.
Explore Courses for Electrical Engineering (EE) exam

Top Courses for Electrical Engineering (EE)

Explore Courses
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