What is the power requirement for pumping 450 litres of water per minute against a head of 50 m, assuming a pump efficiency of 65%? What size (SHP) of electric motor is required?
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In metric units, the constant is 75: \( \text{HP} = \frac{Q \cdot H}{75 \cdot \eta} \) where \( Q \) is in liters per second and \( H \) is in meters.
Using this directly: \( \text{HP} = \frac{7.5 \times 50}{75 \times 0.65} = 7.69 \text{ HP} \), which is rounded to the standard 7.5 HP motor.