What is the rotor speed of a six pole, 60 cycle, induction motor operating at full load with 3% slip?
Official USCG Answer & Rule Citation
Correct Answer: Option A — 1164 RPM
Synchronous speed for a 6-pole, 60 Hz motor is (120 * 60) / 6 = 1200 RPM. Factoring in a 3 percent full-load slip, rotor speed equals synchronous speed multiplied by (1 - 0.03), resulting in 1200 * 0.97 = 1164 RPM.
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