Hydraulic Power Units Eric Bornemann Fall 2008

Power Unit Basics Uses Uses Open and closed center systems Open and closed center systems Parts Parts-Pump -Valves -Valves-Motor-Tank

System Requirements Flow required Flow required Pressure required Pressure required System type System type

Tank Selection Arrangement Arrangement Should be 2 to 4 times the size of volumetric flow Should be 2 to 4 times the size of volumetric flow Take off and return positioned for good circulation Take off and return positioned for good circulation Filler/Breather, Drain, Level Gauge Filler/Breather, Drain, Level Gauge Additional cooling Additional cooling

Pump Selection Displacement per revolution Displacement per revolution Pressure rating Pressure rating Types (gear, piston, screw) Types (gear, piston, screw)

Motor Selection Open Center HP = gpm x psi/(1714 x eff.) Open Center HP = gpm x psi/(1714 x eff.) Closed Center Find RMS HP Closed Center Find RMS HP Maximum torque required Maximum torque required Speed coincides with pump displacement Speed coincides with pump displacement

Valves Open or closed loop Open or closed loop Valve operation Valve operation Valve type Valve type

Summary System Requirements System Requirements System Type System Type Arrangement Arrangement Valve Requirements Valve Requirements