TECH 343 Servo and Nonservo Hydraulics

Experiment #2: Extension And Retraction Speeds Of A Linear Circuit

Equipment
1. Vickers hydraulic training bench
2. Cylinders, vertical and horizontal
3. Directional valve
4. Weight
5. Outside micrometer, 0 - 1"

6. PC w/Labview program

Objectives
1. To determine the effect of relief valve settings on the speed of a linear actuator.
2. To determine the effect of load on the speed of a linear actuator.

Procedure
1. Using the vertical cylinder and the directional valve construct a simple linear circuit.
2. Determine the minimum pressure required for uniform motion of actuator by adjusting the relief valve.
3. Select a relief valve setting slightly greater than the minimum required and stroke the cylinder to full extension.
4. Measure the diameter of the cylinder rod to the nearest .001".
5. Using the directional valve, retract and extend the rod while recording the velocity in each direction.
6. Measure and record the pressure at the rod and cap end during extension and retraction.
7. Select two higher relief valve settings below 400 psig and repeat steps 5 and 6.
8. Set the relief valve at 400 psig and repeat steps 5 and 6.
9. Place the weight on the vertical cylinder and repeat steps 5 and 6 using the 400 psig setting.
10. Using the horizontal cylinder repeat steps 2 through 8.
11. Report your results in tabular form and graph the data using an appropriate format.
12. Using ANSI symbols draw the complete circuit. (Note - you must determine the type of directional valve in the circuit.)

Questions
1. What is the maximum speed of the cylinders in extension and retraction?
2. What is the bore size of the cylinders?
3. What is the flow rate of the pump in gallons per minute?