PRACTICE PROBLEMS

(Note: Problem solutions are available at http://sites.google.com/site/automatedmanufacturingsystems/)

1. A piston is to be designed to exert an actuation force of 120 lbs on its extension stroke. The inside diameter of the cylinder is 2.0” and the ram diameter is 0.375”. What shop air pressure will be required to provide this actuation force? Use a safety factor of 1.3.

2. Draw a simple hydraulic system that will advance and retract a cylinder using PLC outputs. Sketches should include details from the PLC output card to the hydraulic cylinder.

3. Develop an electrical ladder diagram and pneumatic diagram for a PLC controlled system. The system includes the components listed below. The system should include all required safety and wiring considerations.

a 3 phase 50 HP motor

1 NPN sensor

1 NO push button

1 NC limit switch

1 indicator light

a doubly acting pneumatic cylinder

4. What are the trade-offs between 3-phase and single-phase AC power.

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