Question

The maximum horsepower produced by the motor is reached when it is operating at the maximum system pressure and at maximum shaft speed. For example, if a hydraulic motor application required 5 hp at 3000 rpm, with an available supply pressure of 3000 psi and a 100 psi return line pressure loss, the effective pressure differential will be 2900 psi. Calculate:

a) Theoretical torque I
b) Displacement if mechanical efficiency is 85%.

Answer 1

The theoretical torque is 8.75 lb-ft and the displacement is 0.0000203 in³/rev.

Step-by-step explanation:

To calculate the theoretical torque, we can use the following formula:
Torque = (Horsepower × 5252) ÷ RPM

In this case, the horsepower is 5 and the RPM is 3000, so:
Theoretical Torque = (5 × 5252) ÷ 3000 = 8.75 lb-ft

To calculate the displacement, we can use the following formula:
Displacement = (Horsepower × 231) ÷ (RPM × Pressure × Efficiency)

In this case, the horsepower is 5, the RPM is 3000, the pressure is 2900 psi (effective pressure differential), and the efficiency is 85%, so:
Displacement = (5 × 231) ÷ (3000 × 2900 × 0.85) = 0.0000203 in³/rev