# Free Hydraulic Simulation Trial

## Free Sample Training Exercises

These experiments provide examples of the range of training routines that come with the full hydraulic simulation software.

### Understanding Cylinder Load Effects

Experiment: Select circuit: Free - Cylinder Load Experiment

Change the cylinder loads to observe how the different forces effect the circuit design. Change the directional valve centre condition to observe how this is important for circuit safety etc. Test under start-up, standby and normal working conditions to see how your system will perform.

Question: What happens with a large load pushing against the rod and no speed control valves in the circuit?

Consider how the cylinder will move at start up and standby conditions. Could this pose a risk to the operator or cause equipment damage?

Any external load on a cylinder rod will generate pressure inside the cylinder. Without proper control the cylinder will move and could easily generate dangerous, negative pressure in the expanding volume side, as it moves.

### Comparing Fixed and Variable Pumps

Experiment: Select circuit: Free - Pump Energy Usage Comparison

Switch between fixed and variable displacement pumps and check the power consumption between during stand by and working conditions.

Change the directional valve centre conditions to observe how this affects the standby power consumption.

Question: Which spool types are most suitable for use with fixed displacement pumps?

Why might a variable displacement pump provide better energy efficiency than fixed displacement pumps when using a flow control valves?

Open centre spool types are generally more suitable for fixed displacement pumps because they allow the pump flow to pass to the reservoir under standby conditions without raising the pump pressure.

Variable displacement pumps only provide the flow required by the circuit whereas fixed displacement pumps need the circuit to dispose of the excess flow causing heat build-up and energy loss.

### Cylinder Speed Control Experiments

Experiment: Select circuit: Free - Speed Control Example

Operate the directional valve and change the flow control valve settings to see how it affects the cylinder speed. Place the test gauge over the cylinder rod to display the cylinder speed value.

Adjust the load on the cylinder and observe how this affects the cylinder speed.

Question: Why does adjusting the flow control valve change the cylinder speed with a fixed displacement pump?

Why does the cylinder speed change when the cylinder load changes?

Flow control valves only work with fixed displacement pumps if there is a relief valve or somewhere else for the excess flow to go. Without the relief valve, only the pressure would change and the pump would fail if the pressure goes too high.

The flow rate is set as a result of the pressure drop across the orifice and the orifice size. Changing the load on the cylinder will change the pressure drop across the flow control orifice and therefore change the flow through the orifice and cylinder speed.

### Clamping Circuit Example

Experiment: Select circuit: Free - Clamping Circuit Demo

Operate the directional valve to observe how the circuit works.

Switch to design mode then add additional, or move the flow control valve to customise the circuit. Try adding your own, or different, system loads to see how the circuit performs.

Question: Why doesn't the hydraulic motor move before the cylinder retracts?

The motor would start rotating at the same time the cylinder retracts if both had zero load. However, the hydraulic fluid always takes the easiest route and there is not enough supply pressure to rotate the motor until the cylinder is fully retracted.

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