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2. A three phase 3 kV, 24 pole, 50Hz, star connected slip ring induction motor has a rotor resistance of 0.015 Ω and a stand still reactance of 0.265 Ω per phase. Full load torque is obtained at a speed of 245 rpm. Calculate (i) ratio of maximum to full load torque. (ii) Speed at maximum torque. Neglect stator impedance.?
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2. A three phase 3 kV, 24 pole, 50Hz, star connected slip ring inducti...
Calculation of Maximum to Full Load Torque Ratio
Given data:
- Voltage (V) = 3 kV
- Number of poles (p) = 24
- Frequency (f) = 50 Hz
- Rotor resistance (Rr) = 0.015 Ω
- Standstill reactance (Xs) = 0.265 Ω
- Full load speed (Nf) = 245 rpm
To calculate the maximum to full load torque ratio, we need to first find the slip at full load and at maximum torque.
The slip (S) is given by the formula:
S = (Ns - N) / Ns
where Ns is the synchronous speed and N is the rotor speed.
Synchronous speed (Ns) is given by the formula:
Ns = 120 * f / p
Substituting the given values:
Ns = 120 * 50 / 24 = 250 rpm
At full load, N = Nf = 245 rpm
Slip at full load (Sf) = (250 - 245) / 250 = 0.02
To find the maximum torque, we need to calculate the slip at maximum torque (Sm) using the equation:
Sm = Rr / √(Rr^2 + Xs^2)
Substituting the given values:
Sm = 0.015 / √(0.015^2 + 0.265^2) = 0.015 / √(0.000225 + 0.070225) = 0.015 / √0.07045 = 0.015 / 0.265 = 0.0566
Now we can calculate the ratio of maximum to full load torque (Tm/Tf) using the equation:
(Tm/Tf) = (Sm/Sf)^2
Substituting the values of Sm and Sf:
(Tm/Tf) = (0.0566/0.02)^2 = 2.83^2 = 8.01
Hence, the ratio of maximum to full load torque is approximately 8.01.
Calculation of Speed at Maximum Torque
To find the speed at maximum torque, we can use the equation:
Nm = Ns * (1 - Sm)
Substituting the values of Ns and Sm:
Nm = 250 * (1 - 0.0566) = 250 * 0.9434 ≈ 235.85 rpm
Hence, the speed at maximum torque is approximately 235.85 rpm.
Thus, the answers to the given questions are:
(i) The ratio of maximum to full load torque is approximately 8.01.
(ii) The speed at maximum torque is approximately 235.85 rpm.
Given data:
- Voltage (V) = 3 kV
- Number of poles (p) = 24
- Frequency (f) = 50 Hz
- Rotor resistance (Rr) = 0.015 Ω
- Standstill reactance (Xs) = 0.265 Ω
- Full load speed (Nf) = 245 rpm
To calculate the maximum to full load torque ratio, we need to first find the slip at full load and at maximum torque.
The slip (S) is given by the formula:
S = (Ns - N) / Ns
where Ns is the synchronous speed and N is the rotor speed.
Synchronous speed (Ns) is given by the formula:
Ns = 120 * f / p
Substituting the given values:
Ns = 120 * 50 / 24 = 250 rpm
At full load, N = Nf = 245 rpm
Slip at full load (Sf) = (250 - 245) / 250 = 0.02
To find the maximum torque, we need to calculate the slip at maximum torque (Sm) using the equation:
Sm = Rr / √(Rr^2 + Xs^2)
Substituting the given values:
Sm = 0.015 / √(0.015^2 + 0.265^2) = 0.015 / √(0.000225 + 0.070225) = 0.015 / √0.07045 = 0.015 / 0.265 = 0.0566
Now we can calculate the ratio of maximum to full load torque (Tm/Tf) using the equation:
(Tm/Tf) = (Sm/Sf)^2
Substituting the values of Sm and Sf:
(Tm/Tf) = (0.0566/0.02)^2 = 2.83^2 = 8.01
Hence, the ratio of maximum to full load torque is approximately 8.01.
Calculation of Speed at Maximum Torque
To find the speed at maximum torque, we can use the equation:
Nm = Ns * (1 - Sm)
Substituting the values of Ns and Sm:
Nm = 250 * (1 - 0.0566) = 250 * 0.9434 ≈ 235.85 rpm
Hence, the speed at maximum torque is approximately 235.85 rpm.
Thus, the answers to the given questions are:
(i) The ratio of maximum to full load torque is approximately 8.01.
(ii) The speed at maximum torque is approximately 235.85 rpm.
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2. A three phase 3 kV, 24 pole, 50Hz, star connected slip ring induction motor has a rotor resistance of 0.015 Ω and a stand still reactance of 0.265 Ω per phase. Full load torque is obtained at a speed of 245 rpm. Calculate (i) ratio of maximum to full load torque. (ii) Speed at maximum torque. Neglect stator impedance.?
Question Description
2. A three phase 3 kV, 24 pole, 50Hz, star connected slip ring induction motor has a rotor resistance of 0.015 Ω and a stand still reactance of 0.265 Ω per phase. Full load torque is obtained at a speed of 245 rpm. Calculate (i) ratio of maximum to full load torque. (ii) Speed at maximum torque. Neglect stator impedance.? 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 2. A three phase 3 kV, 24 pole, 50Hz, star connected slip ring induction motor has a rotor resistance of 0.015 Ω and a stand still reactance of 0.265 Ω per phase. Full load torque is obtained at a speed of 245 rpm. Calculate (i) ratio of maximum to full load torque. (ii) Speed at maximum torque. Neglect stator impedance.? covers all topics & solutions for Electrical Engineering (EE) 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for 2. A three phase 3 kV, 24 pole, 50Hz, star connected slip ring induction motor has a rotor resistance of 0.015 Ω and a stand still reactance of 0.265 Ω per phase. Full load torque is obtained at a speed of 245 rpm. Calculate (i) ratio of maximum to full load torque. (ii) Speed at maximum torque. Neglect stator impedance.?.
2. A three phase 3 kV, 24 pole, 50Hz, star connected slip ring induction motor has a rotor resistance of 0.015 Ω and a stand still reactance of 0.265 Ω per phase. Full load torque is obtained at a speed of 245 rpm. Calculate (i) ratio of maximum to full load torque. (ii) Speed at maximum torque. Neglect stator impedance.? 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 2. A three phase 3 kV, 24 pole, 50Hz, star connected slip ring induction motor has a rotor resistance of 0.015 Ω and a stand still reactance of 0.265 Ω per phase. Full load torque is obtained at a speed of 245 rpm. Calculate (i) ratio of maximum to full load torque. (ii) Speed at maximum torque. Neglect stator impedance.? covers all topics & solutions for Electrical Engineering (EE) 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for 2. A three phase 3 kV, 24 pole, 50Hz, star connected slip ring induction motor has a rotor resistance of 0.015 Ω and a stand still reactance of 0.265 Ω per phase. Full load torque is obtained at a speed of 245 rpm. Calculate (i) ratio of maximum to full load torque. (ii) Speed at maximum torque. Neglect stator impedance.?.
Solutions for 2. A three phase 3 kV, 24 pole, 50Hz, star connected slip ring induction motor has a rotor resistance of 0.015 Ω and a stand still reactance of 0.265 Ω per phase. Full load torque is obtained at a speed of 245 rpm. Calculate (i) ratio of maximum to full load torque. (ii) Speed at maximum torque. Neglect stator impedance.? in English & in Hindi are available as part of our courses for Electrical Engineering (EE).
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Here you can find the meaning of 2. A three phase 3 kV, 24 pole, 50Hz, star connected slip ring induction motor has a rotor resistance of 0.015 Ω and a stand still reactance of 0.265 Ω per phase. Full load torque is obtained at a speed of 245 rpm. Calculate (i) ratio of maximum to full load torque. (ii) Speed at maximum torque. Neglect stator impedance.? defined & explained in the simplest way possible. Besides giving the explanation of
2. A three phase 3 kV, 24 pole, 50Hz, star connected slip ring induction motor has a rotor resistance of 0.015 Ω and a stand still reactance of 0.265 Ω per phase. Full load torque is obtained at a speed of 245 rpm. Calculate (i) ratio of maximum to full load torque. (ii) Speed at maximum torque. Neglect stator impedance.?, a detailed solution for 2. A three phase 3 kV, 24 pole, 50Hz, star connected slip ring induction motor has a rotor resistance of 0.015 Ω and a stand still reactance of 0.265 Ω per phase. Full load torque is obtained at a speed of 245 rpm. Calculate (i) ratio of maximum to full load torque. (ii) Speed at maximum torque. Neglect stator impedance.? has been provided alongside types of 2. A three phase 3 kV, 24 pole, 50Hz, star connected slip ring induction motor has a rotor resistance of 0.015 Ω and a stand still reactance of 0.265 Ω per phase. Full load torque is obtained at a speed of 245 rpm. Calculate (i) ratio of maximum to full load torque. (ii) Speed at maximum torque. Neglect stator impedance.? theory, EduRev gives you an
ample number of questions to practice 2. A three phase 3 kV, 24 pole, 50Hz, star connected slip ring induction motor has a rotor resistance of 0.015 Ω and a stand still reactance of 0.265 Ω per phase. Full load torque is obtained at a speed of 245 rpm. Calculate (i) ratio of maximum to full load torque. (ii) Speed at maximum torque. Neglect stator impedance.? tests, examples and also practice Electrical Engineering (EE) tests.
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