Thirteen individual lessons make up the ITC Learning On-Line Hydraulics Library. ITC Learning’s Hydraulics library was specifically developed for beginning hydraulics technicians, mechanics, electricians, and operators who need to know about industrial hydraulic power.

Introduction to Hydraulic Systems


Hydraulic Schematics


Hydraulic Fluid


Hydraulic Pump Applications


Positive Displacement Pumps


Hydraulic Accumulators


Pressure Control Principles


Pressure Control Operation


Pressure Control Valve Application


Directional Control Principles


Flow Control Valves


Actuator Cylinders


Hydraulic Motors

• Visually identify the basic components of an industrial hydraulic system.
• Describe the function of the basic components of an industrial hydraulic system.
• Understand Pascal’s Law.
• Use Pascal’s Law to determine the pressure and flow at a given point in a simple hydraulic system.
• Describe the transmission of power through the system using a diagram of a simple hydraulic system.
• Describe conditions necessary for normal operation of a pressure relief valve.
• Define work and power as they relate to hydraulics.
• Describe the conversion of power through the hydraulic system.
• Calculate electrical horsepower and piston speed, given the appropriate variables.

• Identify the schematic symbols for the basic components of a hydraulic system.
• Identify the pressure at a given point in a hydraulic system using color-coding.
• Identify the flow path through a simple hydraulic system, given a schematic for a simple hydraulic system.

• Describe the types, properties, and functions of hydraulic fluid that make power transmission possible.
• List sources of fluid contamination and ways to avoid contamination.
• List the purposes of a hydraulic reservoir.
• Identify the components of a hydraulic reservoir and describe their functions.
• Describe the conditions necessary for proper functioning of a hydraulic reservoir.
• Identify the location of hydraulic filters at various points in a schematic representation of a hydraulic system.
• Describe the purposes of hydraulic filters.
• Describe the purpose and function of the by-pass valve.
• Describe the functions of hydraulic piping.
• Describe the conditions necessary for proper functioning of hydraulic piping and connections and identify common indicators of malfunction.

• Describe the role of the pump in hydraulic power transmission given a pictorial drawing or a system schematic.
• Calculate the actual flow rate and the volumetric efficiency in a hydraulic system.
• Explain the effect of the position of the reservoir in relation to the operation of the inlet side of the pump.
• Recognize symptoms of pump malfunction, such as cavitation and aeration, and identify likely causes.

• Identify the components of fixed and variable volume vane pumps, and describe their functions.
• Identify the components of bent axis and axial piston pumps, and describe their functions.
• Explain causes of system inefficiencies associated with fixed volume pumps.
• Describe applications for variable volume pumps.

• Identify and describe the application of an accumulator in a system.
• Identify common types of accumulators.
• Identify safety considerations for depressurizing and pre-charging an accumulator.
• Describe how an accumulator operates in a hydraulic system.

• Describe the functions of a pressure relief valve in a hydraulic system using a system schematic.

• Explain the operation of a direct-acting poppet type pressure control valve.
• Explain the operation of a pilot operated pressure control valve.
• Explain the operation of a normally open pressure control valve.
• Distinguish between the components and operation of direct-acting, pilot operated and normally open pressure control valves.

• Describe how an unloading pressure control valve operates.
• Describe how a counterbalance valve operates.
• Describe the proper operation of a pressure control valve in a sequencing circuit.
• Describe the proper operation of a pressure control valve in a pressure reducing circuit.
• Describe the proper operation of a check valve.

• Identify the schematic symbols for various types of directional control valves.
• Identify the functions of the ports on a directional control valve.
• Trace the various flow paths through the directional control valve using a system schematic.
• Describe how different kinds of directional control valves can be used to control the operation of a hydraulic cylinder using a system schematic.
• Describe centering conditions commonly used in directional control valves.
• Describe piloting arrangements commonly used with directional control valves.

• Explain the conditions that affect flow in a hydraulic system using a system schematic.
• Explain how changing the flow rate in a hydraulic system affects the performance of the actuator using a system schematic.
• Identify the schematic symbols for flow control valves.
• Identify the functions of ports on a flow control valve.
• Describe the operation of a needle valve, and trace the path of the fluid through the valve.
• Describe the operation of a pressure-compensated flow control valve, and trace the path of the fluid through the valve.
• Describe the operation of a check valve.
• Describe the operation of meter-in and meter-out circuits using a system schematic.

• Describe the difference between a single-acting cylinder and a double-acting cylinder.
• Identify the schematic symbol and describe the action of a differential cylinder.
• Using the schematic symbol, describe the operation and applications of a non-differential cylinder.
• Describe the operation of a circuit whose cylinder is controlled by regulating flow or pressure.
• Identify the components of a hydraulic cylinder using a cutaway model.
• Explain the purpose of a cylinder leak test.

• Identify the schematic symbol for an unidirectional and bi-directional hydraulic motor.
• Describe the functional similarity between a hydraulic pump and a hydraulic motor.
• Describe the flow path through a hydraulic motor, using a cutaway diagram of a vane motor.
• Describe the operation of a hydraulic gear motor and a hydraulic piston motor, using a cutaway diagram of each.
• Express the output of a hydraulic motor in terms of horsepower.
• Describe the operation of various hydrostatic drive circuits from the circuit schematics.
• Describe the function of the components and the flow path through the circuit.