Hydraulic Motors & Accessories

How to Choose the Right Hydraulic Motor

Size for torque first, verify speed range second, and confirm pressure and flow compatibility before specifying the final unit.

• Calculate Required Torque Output Torque is the primary sizing criterion for a hydraulic motor. Motor torque (lb-in) equals displacement (cc/rev) multiplied by operating pressure (PSI), divided by 24.1. Undersizing torque capacity causes the motor to stall under load or fail prematurely; oversizing wastes energy and system flow. Identify the worst-case load condition — including startup friction and dynamic peaks — before selecting displacement.
• Match Speed Range to Application Hydraulic motors are rated for minimum and maximum RPM, and the right type depends on where your application falls. Low-speed/high-torque (LSHT) motors like gerolers and geroters operate efficiently from 10–300 RPM and are ideal for wheel drives, winches, and augers. Gear and piston motors run at 1,000–4,000+ RPM and are suited for conveyor drives, fans, and rotary tooling.
• Verify Pressure and Flow Compatibility Confirm the motor’s continuous and intermittent pressure ratings exceed your system’s operating pressure with adequate margin. Then calculate required pump flow: GPM = (displacement in cc/rev × RPM) ÷ 231. Mismatched flow starves the motor at speed or causes overspeed damage. Ensure your pump, relief valve settings, and line sizing all support the motor’s operating window before specifying the final unit.