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The synchronous speed of induction motor is 900 RPM. Under blocked-rotor condition the input power to the motor is 45 KW at 193.6 A. The stator resistance per phase is 0.2 Ω and the transformation ratio is a = 2. Calculate the motor starting torque (in N-m)
Correct answer is between '238,239'. Can you explain this answer?
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Verified Answer
The synchronous speed of induction motor is 900 RPM. Under blocked-rot...
R2 = 0.05 Ω
Referred to the rotor resistance per phase is
R′2 = a2R2 = 0.2Ω
∴ Starting torque 
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The synchronous speed of induction motor is 900 RPM. Under blocked-rot...
Ohms and the stator reactance per phase is 0.3 ohms. The rotor resistance per phase is 0.1 ohms. The rotor reactance per phase is 0.2 ohms. Calculate the slip and the torque developed by the motor under blocked-rotor condition.
To calculate the slip, we can use the formula:
Slip = (Synchronous speed - Actual speed) / Synchronous speed
Since the motor is under blocked-rotor condition, the actual speed is 0 RPM. Therefore, the slip can be calculated as:
Slip = (900 - 0) / 900
Slip = 1
The slip is 1, which means the motor is not rotating at all under blocked-rotor condition.
To calculate the torque developed by the motor, we can use the formula:
Torque = (3 * V^2 * R2) / (s * ωs * ((R1 + R2)^2 + (X1 + X2)^2))
Where:
V = Line voltage
R1 = Stator resistance per phase
R2 = Rotor resistance per phase
X1 = Stator reactance per phase
X2 = Rotor reactance per phase
s = Slip
ωs = Angular synchronous speed
In this case, the line voltage is not given, so we cannot calculate the torque accurately.
However, assuming a line voltage of 415 V, we can calculate the torque by substituting the given values into the formula:
Torque = (3 * 415^2 * 0.1) / (1 * 2π * 900/60 * ((0.2 + 0.1)^2 + (0.3 + 0.2)^2))
Torque = 3.57 Nm
Therefore, under blocked-rotor condition, the torque developed by the motor is approximately 3.57 Nm.
To calculate the slip, we can use the formula:
Slip = (Synchronous speed - Actual speed) / Synchronous speed
Since the motor is under blocked-rotor condition, the actual speed is 0 RPM. Therefore, the slip can be calculated as:
Slip = (900 - 0) / 900
Slip = 1
The slip is 1, which means the motor is not rotating at all under blocked-rotor condition.
To calculate the torque developed by the motor, we can use the formula:
Torque = (3 * V^2 * R2) / (s * ωs * ((R1 + R2)^2 + (X1 + X2)^2))
Where:
V = Line voltage
R1 = Stator resistance per phase
R2 = Rotor resistance per phase
X1 = Stator reactance per phase
X2 = Rotor reactance per phase
s = Slip
ωs = Angular synchronous speed
In this case, the line voltage is not given, so we cannot calculate the torque accurately.
However, assuming a line voltage of 415 V, we can calculate the torque by substituting the given values into the formula:
Torque = (3 * 415^2 * 0.1) / (1 * 2π * 900/60 * ((0.2 + 0.1)^2 + (0.3 + 0.2)^2))
Torque = 3.57 Nm
Therefore, under blocked-rotor condition, the torque developed by the motor is approximately 3.57 Nm.
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The synchronous speed of induction motor is 900 RPM. Under blocked-rotor condition the input power to the motor is 45 KW at 193.6 A. The stator resistance per phase is 0.2 Ω and the transformation ratio is a = 2. Calculate the motor starting torque (in N-m)Correct answer is between '238,239'. Can you explain this answer?
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The synchronous speed of induction motor is 900 RPM. Under blocked-rotor condition the input power to the motor is 45 KW at 193.6 A. The stator resistance per phase is 0.2 Ω and the transformation ratio is a = 2. Calculate the motor starting torque (in N-m)Correct answer is between '238,239'. 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 The synchronous speed of induction motor is 900 RPM. Under blocked-rotor condition the input power to the motor is 45 KW at 193.6 A. The stator resistance per phase is 0.2 Ω and the transformation ratio is a = 2. Calculate the motor starting torque (in N-m)Correct answer is between '238,239'. 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 The synchronous speed of induction motor is 900 RPM. Under blocked-rotor condition the input power to the motor is 45 KW at 193.6 A. The stator resistance per phase is 0.2 Ω and the transformation ratio is a = 2. Calculate the motor starting torque (in N-m)Correct answer is between '238,239'. Can you explain this answer?.
The synchronous speed of induction motor is 900 RPM. Under blocked-rotor condition the input power to the motor is 45 KW at 193.6 A. The stator resistance per phase is 0.2 Ω and the transformation ratio is a = 2. Calculate the motor starting torque (in N-m)Correct answer is between '238,239'. 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 The synchronous speed of induction motor is 900 RPM. Under blocked-rotor condition the input power to the motor is 45 KW at 193.6 A. The stator resistance per phase is 0.2 Ω and the transformation ratio is a = 2. Calculate the motor starting torque (in N-m)Correct answer is between '238,239'. 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 The synchronous speed of induction motor is 900 RPM. Under blocked-rotor condition the input power to the motor is 45 KW at 193.6 A. The stator resistance per phase is 0.2 Ω and the transformation ratio is a = 2. Calculate the motor starting torque (in N-m)Correct answer is between '238,239'. Can you explain this answer?.
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The synchronous speed of induction motor is 900 RPM. Under blocked-rotor condition the input power to the motor is 45 KW at 193.6 A. The stator resistance per phase is 0.2 Ω and the transformation ratio is a = 2. Calculate the motor starting torque (in N-m)Correct answer is between '238,239'. Can you explain this answer?, a detailed solution for The synchronous speed of induction motor is 900 RPM. Under blocked-rotor condition the input power to the motor is 45 KW at 193.6 A. The stator resistance per phase is 0.2 Ω and the transformation ratio is a = 2. Calculate the motor starting torque (in N-m)Correct answer is between '238,239'. Can you explain this answer? has been provided alongside types of The synchronous speed of induction motor is 900 RPM. Under blocked-rotor condition the input power to the motor is 45 KW at 193.6 A. The stator resistance per phase is 0.2 Ω and the transformation ratio is a = 2. Calculate the motor starting torque (in N-m)Correct answer is between '238,239'. Can you explain this answer? theory, EduRev gives you an
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