GATE 2025 ME – Question 53
Consider a Pelton wheel of 1 m diameter. The magnitude of relative velocity of water at the bucket inlet is same as the magnitude of relative velocity of water at the bucket exit. The absolute speed of water at the bucket inlet is 125.66 m s$^{-1}$. For maximum power output from the Pelton wheel, the rpm of the Pelton wheel is ____________ (rounded off to 1 decimal place).
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Correct answer: 1194.00 to 1206.00
Explanation
For maximum power in a Pelton wheel, the bucket speed is half of the jet speed, $U = \frac{V}{2} = 62.83$ m/s. The wheel diameter is 1 m, so $N = \frac{60U}{\pi D} = \frac{60 \times 62.83}{\pi \times 1} = 1200.0$ rpm.