What is the rotor speed for a 4‑pole, 60 Hz squirrel‑cage motor with a slip of 3.76%?

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Multiple Choice

What is the rotor speed for a 4‑pole, 60 Hz squirrel‑cage motor with a slip of 3.76%?

Explanation:
Rotor speed is the rotating magnetic field speed (synchronous speed) reduced by the slip percentage. For a four-pole machine at 60 Hz, the synchronous speed is Ns = 120 f / P = 120 × 60 / 4 = 1800 rpm. With a slip of 3.76%, the rotor speed is n = Ns × (1 − s) = 1800 × (1 − 0.0376) = 1800 × 0.9624 ≈ 1732 rpm. So the rotor runs about 1732 rpm. The other numbers would correspond to applying no slip (1800 rpm) or using a different slip value or pole count.

Rotor speed is the rotating magnetic field speed (synchronous speed) reduced by the slip percentage. For a four-pole machine at 60 Hz, the synchronous speed is Ns = 120 f / P = 120 × 60 / 4 = 1800 rpm. With a slip of 3.76%, the rotor speed is n = Ns × (1 − s) = 1800 × (1 − 0.0376) = 1800 × 0.9624 ≈ 1732 rpm. So the rotor runs about 1732 rpm. The other numbers would correspond to applying no slip (1800 rpm) or using a different slip value or pole count.

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