1. Working Pressure and Rated Pressure
Working Pressure: The actual pressure of the hydraulic fluid input to the motor, its magnitude determined by the motor load. The difference between the motor inlet pressure and outlet pressure is called the motor differential pressure. Rated Pressure: The pressure required for the motor to operate continuously and normally, as specified by testing standards.
2. Displacement and Flow Rate
Displacement: The volume of fluid required to power the hydraulic motor per revolution, assuming no leakage. Vm (m³/rad) Flow Rate: The theoretical flow rate qMt without considering leakage; the actual flow rate qM considering leakage.
3. Volumetric Efficiency and Speed
Volume Efficiency ηMv: The ratio of actual input flow rate to theoretical input flow rate.
4. Torque and Mechanical Efficiency
The output power equals the input power, assuming no motor losses. Actual Torque T: The loss torque ΔT caused by actual mechanical losses in the motor, making it smaller than the theoretical torque Tt. The mechanical efficiency ηMm is equal to the ratio of the actual output torque to the theoretical output torque.
5. Power and Overall Efficiency
The actual input power of the motor is pqM, and the actual output power is Tω. The overall motor efficiency ηM is the ratio of the actual output power to the actual input power. Hydraulic motors have two types of circuits: series circuits and braking circuits. These two types of circuits can be further classified. One type of series circuit involves connecting three hydraulic motors in series, with a directional valve controlling their starting, stopping, and direction.
