Start with output torque
Separate continuous, peak and starting torque. A winch or rotary drive that starts under load can require substantially more starting torque than its steady running condition.
Use pressure available across the motor after return pressure and circuit losses, not the pump setting as though all of it reaches the motor.
Confirm the actual speed range
Record minimum, normal and maximum speed. A motor that operates well at 100 rpm may not remain smooth at 5 rpm under heavy load. Minimum stable speed is as important as maximum speed when the machine creeps, positions or lowers a load.
Match pressure and flow
| Selection item | Confirm | Why it matters |
|---|---|---|
| System pressure | Working and peak pressure | Available torque and motor stress |
| Oil flow | Normal and maximum flow | Speed range |
| Return line | Backpressure and drain condition | Seal life, heat and efficiency |
| Oil temperature | Normal and maximum temperature | Viscosity, leakage and durability |
Choose the structure for the duty
For compact intermittent drives with moderate load, an orbital motor can be economical. Frequent starts, heavy pulling, continuous rotary duty or shock loading may favor a radial piston design. JHM and JNM are radial piston families, while BM covers orbital configurations. QJM is a low-speed high-torque radial ball-piston motor with a floating rotor and spherical raceway. Each family covers different ranges; check the selected model data.
Confirm mechanical and hydraulic interfaces
- Flange pilot, bolt pattern and available envelope
- Spline, key or custom shaft dimensions and external loads
- Port size, orientation, flow direction and case drain
- Brake, counterbalance, flushing and anti-cavitation functions
- Oil viscosity, contamination, ambient temperature and duty cycle
Decide whether a brake or manifold is needed
Winches, slewing drives and wheel drives may need a mechanical brake, counterbalance valve, relief valve, flushing circuit or custom manifold. Do not rely on internal leakage resistance to hold a suspended or rolling load.
Information for model selection
- Application and driven machine
- Continuous, peak and starting torque
- Minimum, normal and maximum speed
- Available pressure and flow
- Duty cycle and environment
- Flange, shaft, ports and installation drawing
- Brake, valve or replacement requirement
For winches, continue with the hydraulic motor for winch drive guide.
Technical information is provided for preliminary selection. Confirm the selected model, installation and application requirements before ordering.