07 Mar Understanding and Choosing a Hydraulic System Design

Proper selection and installation of all hydraulic components in your winch system will ensure that your winch components perform as they should and are free of constant maintenance problems. Understanding the basic function, design, and components can help confirm proper selection and optimum usage for any hydraulic winch application.

The basic concept of any hydraulic system is simple: Force that is applied at one point is transmitted to another point using an incompressible fluid, yet every hydraulic system design will be unique to the application.  A few hydraulic system components will be common for winch usages, such as pump/power take-offs and directional control valves.

The following component information is general in nature and will be helpful in choosing a hydraulic system design for a winch.  It is always wise to consult a qualified hydraulic distributor, like Winches Inc, if you have specific questions about your system.

Pump/Power Take-Offs
The hydraulic pump and PTO selected should be chosen to deliver the proper flow at any engine speed you want to run.  For example, with an engine running at 1200 RPM, using a PTO which runs at 70% engine speed, a winch requiring 18 GPM flow for the line speed needed, the pump selected must be capable of delivering 18 GPM at 840 RPM, as that is what the PTO requires to operate.  Also, the pump must be pressure rated for at least the setting of the relief valve.

Another important consideration on pump selection is to select the proper rotation.  Most pumps are not bi-rotational; that is, they will function properly only in one direction of rotation.  For example, if a PTO provides engine-wise rotation and the pump is mounted behind it with the shaft toward the front, a “right hand” or clockwise rotation of the pump is required.  Other directions of mounting either the pump or PTO will affect the direction of rotation, so they must be considered in your selection.

Directional Control Valves

The typical directional control valve to be used with a winch is a three-position, four-way valve with an open center spool which is spring returned in neutral.  The open center spool is often referred to as a “motor” spool since its most common function is providing flow to hydraulic motors. In most winch applications, the spool should be spring returned to neutral, since this serves as a safety feature.  As soon as the operator’s hand is removed from the valve lever the winch will stop running.

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