Coast Guard Exams
Question 351Electricity/Electronics - QMED70% to pass

What is the rotor speed of a six pole, 60 cycle, induction motor operating at full load with 3% slip?

AI Explanation
The correct answer is A) 1164 RPM. To calculate the rotor speed of a six-pole, 60-cycle induction motor operating at full load with 3% slip, we can use the formula: Rotor speed (RPM) = (120 x f) / (number of poles) x (1 - slip) Where: f = frequency (60 Hz) Number of poles = 6 Slip = 3% (0.03) Plugging in the values: Rotor speed = (120 x 60) / 6 x (1 - 0.03) = 1200 x 0.97 = 1164 RPM The other options are incorrect because: B) 1746 RPM is the synchronous speed, not the rotor speed. C) 1800 RPM is not the correct calculated value. D) 3492 RPM is double the synchronous speed, which is not possible for a six-pole induction motor.