Question:
The frequencies of the stator and rotor currents flowing in a three-phase 8-pole induction motor are 40 Hz and 1 Hz respectively. The motor speed, in rpm, is ________. (round off to nearest integer)
The frequencies of the stator and rotor currents flowing in a three-phase 8-pole induction motor are 40 Hz and 1 Hz respectively. The motor speed, in rpm, is ________. (round off to nearest integer)
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To calculate the speed of an induction motor, use the formula \( N = \frac{120 \times f}{P} \), where \( f \) is the stator frequency and \( P \) is the number of poles.
Updated On: Nov 27, 2025
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Correct Answer: 580
Solution and Explanation
The motor speed \( N \) in rpm can be calculated using the formula:
\[
N = \frac{120 \times f}{P}
\]
Where:
- \( f \) is the frequency of the stator current,
- \( P \) is the number of poles.
Given: - \( f = 40 \, \text{Hz} \),
- \( P = 8 \) poles,
Substituting the values into the formula: \[ N = \frac{120 \times 40}{8} = 600 \, \text{rpm}.
\] Thus, the motor speed is \( \boxed{600} \) rpm.
- \( P \) is the number of poles.
Given: - \( f = 40 \, \text{Hz} \),
- \( P = 8 \) poles,
Substituting the values into the formula: \[ N = \frac{120 \times 40}{8} = 600 \, \text{rpm}.
\] Thus, the motor speed is \( \boxed{600} \) rpm.
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