Hydraulic Motor Calculator
Calculate hydraulic motor output torque from pressure drop, displacement, and mechanical efficiency.
How it works
- 1Enter the pressure drop across the motor (bar or psi) and the displacement in cc/rev.
- 2Set the mechanical efficiency to account for internal friction.
- 3The calculator applies T = ΔP·V/(2π)·η and returns torque in N·m or lbf·ft.
Use cases
- Sizing a hydraulic motor drive for a conveyor or winch.
- Verifying a motor produces enough torque at the available pressure.
- Comparing theoretical and actual torque to assess efficiency losses.
Frequently asked questions
What is the motor torque formula?
T = ΔP·V/(2π)·η, where ΔP is the pressure drop (Pa), V the displacement per revolution (cc/rev × 1e-6 m³), and η the mechanical efficiency. At 200 bar, 80 cc/rev, 90%: T ≈ 229 N·m.
How does mechanical efficiency affect torque?
It accounts for internal friction. A 90% efficient motor delivers 90% of the theoretical torque; the rest is lost to heat. Both values are shown for comparison.
Can I use psi and lbf·ft?
Yes — switch to imperial and pressure becomes psi with torque in lbf·ft, while the maths runs in SI internally.
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