PMMI Fluid Power Practice Test

These questions are part of the practice quiz. Start practicing

• What is the simplest way to test a pneumatic circuit for small air leaks?
• What is the primary function of a hydraulic accumulator?
• In hydraulic systems, what property of the fluid is most critical for the transmission of force?
• A double-acting cylinder is operated by a 4/2 pilot operated spring return control valve. When the pilot is energized, the cylinder extends. When the pilot is removed, the cylinder does not retract. A possible cause is __________.
• Explain what "pressure drop" means in a hydraulic system.
• What type of valve is used to control the flow direction in a hydraulic circuit?
• What is the primary function of a check valve in a hydraulic system?
• Which of the following is necessary in order to use a vacuum cup to lift a porous material, such as a corrugated sheet for stacking?
• What is a common characteristic of pneumatic systems compared to hydraulic systems?
• Why is regular fluid replacement important in hydraulic systems?
• The oil level in a lubricator is checked ___________ and replenished with ____________?
• Which property of hydraulic fluid is critical for its ability to operate at various temperatures?
• Hydraulics use _____________ fluid while pneumatics use _______________ fluid.
• What is typically the first step in troubleshooting a pneumatic system failure?
• What risk occurs if both solenoids on an AC double solenoid valve become actuated simultaneously?
• What role does a hydraulic actuator play in a hydraulic system?
• What is a common cause of overheating in hydraulic systems?
• Which factor does not affect the Flow Coefficient (Cv)?
• Which formula calculates hydraulic motor torque?
• What does a pressure gauge measure in a hydraulic system?
• Which of the following is a common symptom of a malfunctioning pressure regulator?
• What is a proper repair procedure for damaged flared or flareless steel tube fittings?
• What type of pump is most commonly used in hydraulic systems for high-pressure applications?
• Which of the following measurements would not be best performed with a differential manometer?
• What is the primary purpose of hydraulic fluid in a system?
• How does pressure differ between hydraulic and pneumatic systems?
• Which type of valve is used if an actuator must be operated from two or more locations?
• How is a single-acting cylinder characterized?
• What component in a hydraulic system is responsible for converting hydraulic energy back to mechanical energy?
• Which of the following is not a good troubleshooting method?
• Which of the following pressure types considers the pressure of the surrounding air to be zero?
• Identify an example of a safety device in hydraulic systems.
• What is the purpose of a manifold in hydraulics?
• In a situation involving a maintenance electrician and a pneumatic technician, who is responsible for installing the lockout/tagout on the electrical power sources?
• What does a pressure relief valve do in a hydraulic circuit?
• What effect does turbulence have on fluid flow in hydraulic systems?
• What factor is crucial for selecting hydraulic fluid?
• What does the term "hydraulic actuators" include?
• How does a designed fluid power troubleshooting flow chart assist the technician?
• Which of the following pneumatic motor type has a swash plate?
• Why must hydraulic hoses contain slack?
• How does a check valve function in a hydraulic circuit?
• The purpose of a fluid power motor is to convert fluid power pressure to ___________ motion.
• What is necessary to ensure freedom from water contamination in a fluid system?
• What can be one consequence of using the wrong hydraulic fluid?
• What can excessive vibration in a hydraulic system indicate?
• The sum of the pressure drop in a fluid power loop equals ___________.
• What is the purpose of the adjustment spring in a pressure regulator?
• Which component is typically used to regulate pressure in a hydraulic system?
• What is the primary function of a fluid power schematic diagram?
• What is the purpose of hydraulic fluid in a system?
• What is the intended use for a sight gauge on a hydraulic reservoir?
• What does a check valve do in a hydraulic circuit?
• What type of fluid power component is most common in industrial applications to convert hydraulic energy into mechanical energy?
• What does a pressure relief valve prevent in a hydraulic system?
• What is a double-acting cylinder?
• What is a common sign of hydraulic fluid leaks?
• In a hydraulic system, what role does the hydraulic fluid play during operation?
• What is a purpose of a manual override on a solenoid-operated directional control valve?
• In a hydraulic system, what does a pressure gauge measure?
• What is a "hydraulic circuit"?
• What is one advantage of hydraulic systems over mechanical systems?
• How does a technician compute differential pressure associated with a fluid power component?
• What typically causes cylinder drift in a pneumatic system?
• Which of the following would most likely result in a decrease in system efficiency?
• A space with an absolute pressure of less than one atmosphere may be considered __________.
• Which component is primarily responsible for amplifying force in a hydraulic system?
• What do "L/min" and "GPM" measure in fluid power?
• What typically indicates that a hydraulic cylinder is leaking?
• Which of the following best describes hydraulic fluid?
• Which fixed displacement pump is least likely to suffer catastrophic failure and why?
• Which factor can greatly affect the efficiency of a hydraulic system?
• Which of the following vacuum pump types has an automotive style piston with a connecting rod and a crankshaft?
• What type of troubleshooting tool asks a series of questions with yes or no answers?
• Which is a common application of pneumatic systems?
• What is required for the operation of the jaw on a packaging machine that uses a two-position solenoid operated directional control valve?
• Which valve type is best suited for a fluid power logic circuit controlling a reciprocating cylinder?
• Which method of removing water vapor from a pneumatic system deposits water on the solid surface of solid media?
• What is the force output of an extending cylinder if the piston diameter is 2", the rod diameter is 0.5", and the fluid pressure is 65psi?
• What is the key difference between open-loop and closed-loop hydraulic systems?
• How can fluid contamination affect a hydraulic system?
• What is a meter-in flow control configuration?
• What is a hydraulic schematic symbol?
• A pneumatic filter is continually passing long thin particles. How can this be prevented?
• A pneumatic cylinder is unable to move its load to full extension. What is not a probable cause for this failure?
• What does a filter do in a fluid power system?
• How do you define Bernoulli's principle in fluid dynamics?
• What is the primary source of energy for hydraulic systems?
• What is the most likely cause of pneumatic/hydraulic motor failure?
• Name one common type of hydraulic pump.
• What is the standard pipe schedule for pipe sizes that are from 1/8" to 10" in general industry?
• A packaging machine required 65psi for normal operation. If one actuator stops operating at higher speeds despite consistent pressure, what could be the cause?
• In hydraulic systems, what does the term "actuation" refer to?
• What is one purpose of hydraulic filters?
• What is the purpose of the drain on a pressure sequence valve?
• What is hydraulic fluid typically made of?
• Which of the following is NOT compensated for by a threaded pipe expansion joint?
• Which of the following would be a proper solution if a vane style vacuum pump loses vacuum?
• Name an application where hydraulic systems are frequently used.
• Which type of valve allows fluid to flow in one direction only?
• Which of the following is NOT a test that can be performed on a fluid power component?
• Which of the following will not be removed from air by a filter?
• What does the acronym PSI stand for in hydraulic systems?
• What role do solenoid valves play in hydraulic circuits?
• What type of maintenance is essential for hydraulic systems?
• What is an advantage of using biodegradable hydraulic fluids?
• Which of the following are two guidelines for filter mounting?
• What is the purpose of a flow meter in a fluid power system?
• What role does a hydraulic actuator play in a system?
• What is a common cause of hydraulic fluid contamination?
• Which of the following can be used to control actuator speed?
• What is the main consequence of hydraulic system leaks?
• Which of the following causes a single acting cylinder to retract?
• When dry cutting a hose, what is one way to ensure maximum cutting wheel life?
• What is a basic first step to analyze a pneumatic control system for correct operation?
• What type of connector is commonly used for joining hydraulic hoses securely?
• What does a limit switch do in a hydraulic system?
• How can you calculate the force produced by a hydraulic cylinder?
• Which of the following is NOT a characteristic of hydraulic systems?
• What type of fluid is typically used in pneumatic systems?
• What type of actuator mounting is best for an application requiring pivoting motion of sealing jaws on a packaging machine?
• What does the term "gauge pressure" refer to in fluid dynamics?
• How does fluid viscosity impact pumping efficiency?
• Define "hydraulic power."
• In fluid power, what does the term "actuator" refer to?
• Which is not a likely cause of low system air pressure?
• Which of the following is the cylinder bore area necessary for an application with 80 psi requiring 800 lbs force?
• What is an effect of high viscosity in hydraulic fluid?
• What is the primary function of a hydraulic pump?
• To measure fluid flow with a roto meter, what must a technician do?
• Air pressure at sea level equals ____________ inches of mercury?
• Which of the following correctly pairs components with their definitions regarding pipe and tube sizes?
• What is the function of a hydraulic reservoir?
• Before starting a hydraulic power unit, the pressure relief valve should be completely open to allow the pump to start at what pressure?
• Identify a common seal material for hydraulic applications.
• What component is most likely responsible for a loss of pressure in a pneumatic system?
• What happens to the pressure in a hydraulic system when the fluid is compressed?
• What component is critical for the functionality of a solenoid valve in a fluid power system?
• What is the significance of a fluid filter in a hydraulic system?
• What is the significance of "system pressure" in a hydraulic circuit?
• What does ¼" NPT represent when written on a fluid power drawing?
• Describe the term "hydraulic locking."
• What is "cavitation" in hydraulic systems?
• What does the term "crossover relief" refer to in a hydraulic circuit?
• What can be a consequence of low pressure in a fluid power system?
• In replacing a cylinder, if the pressure and flow rate remain constant, how will a larger rod diameter affect extension and retraction?
• Which process creates air pressure in a pneumatic system?
• What explains why the advancing speed and the retracting speed are different on a double acting cylinder?
• When using flared steel tubing in a fluid power system, the fitting used to mate with the tube will have ___________ threads?
• What is the purpose of a sequence valve?
• What defines a variable displacement pump?
• Which component is essential for maintaining consistent pressure in a fluid power system?
• In a hydraulic system, what is the purpose of a relief valve?
• What hazard is eliminated when the electrical lockout/tagout process is implemented for a fluid power system?
• Why should a technician use extreme caution when disconnecting air lines although lockout/tagout procedures are in place?
• In which condition would you use a pneumatic pressure relief valve?
• Which component reseats a pressure relief valve when fluid drops below its settings?
• Why is it necessary to wear safety glasses when threading pipe?
• Which component is essential for preventing pressure overload in a hydraulic system?
• Which of the following describes how a technician can determine the trade size of a pipe?
• Which factor most affects the selection of hydraulic fluid for a specific application?
• The term "cavitation" in hydraulic systems refers to what phenomenon?
• If the gauge pressure is 87 psi, what is the equivalent reading in bar?
• What common issue might be indicated by the sound of grinding in a hydraulic pump?
• What is commonly used to prevent contamination in hydraulic systems?
• A palletizer with vacuum cups picks up a case and positions it on a waiting pallet. A limit switch detects what?
• What is the most probable effect of a side loaded cylinder?
• How can a technician increase the speed of a cylinder?
• What is the approximate retraction force that a 2 inch bore cylinder with a 0.5 inch diameter rod will develop with an 80 psi air supply?
• What is the primary purpose of using hydraulic fluid in systems?
• What is the role of an accumulator in a hydraulic system?
• What is the purpose of a hydraulic reservoir?
• What type of monitoring device can detect fluid levels in a reservoir?
• How can overheating in a hydraulic system be prevented?
• What is the function of a flow control valve?
• Which of the following is not part of the calculation to determine hydraulic hose pressure drop?
• Which of the following devices indicates to a control system that a vacuum system has reached the setpoint?
• Which of the following components assists in creating vacuum pressure in a pneumatic system?
• What is the function of an orifice in a hydraulic system?
• When taking a pressure measurement at a built-in test fitting, when should the test valve be opened?
• What does a "quick disconnect" coupling do?
• What condition could result from running a hydraulic pump dry?
• Why is regular maintenance crucial for hydraulic systems?
• Which component is essential for controlling the direction of fluid flow in a hydraulic circuit?
• To determine why a venturi tube is not operating properly, the technician should check with which of the following?
• How can you improve the efficiency of a hydraulic system?
• What term describes when a mechanical device is used to prevent movement in an air operated clamping device?
• What type of signal is commonly required for pneumatics in automated systems?
• How does temperature affect hydraulic fluid viscosity?
• When analyzing a hydraulic circuit, which component would prevent fluid from returning to a reservoir when the circuit is pressurized?
• Which fluid power component is primarily responsible for the control of system pressure?
• What could cause a pneumatic pressure regulator to fail after installation?
• What is a risk of using a manometer to measure an unknown vacuum?
• What is the most significant problem with minor air leaks?
• The manual override on a directional control valve is intended for __________ and not for ________?
• What is "compressibility" in relation to hydraulic fluids?
• What kind of fluid is typically used in hydraulic systems?
• Which equation would a technician use when calculating Boyle's law?
• What is the purpose of an exhaust restrictor?
• Explain what a proportional valve does.
• If an actuator fails shortly after replacement, which is a likely cause?