IFPS CFPS flashcards
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31 cards. Read the term and the definition here. The deck at the top of this page is optional.
- Pascal's principle
- Pressure applied to a confined fluid is transmitted undiminished in all directions, allowing force multiplication in hydraulic systems with different piston areas.
- Flow continuity equation
- For steady flow in a closed system, Q = A × v, meaning flow rate equals cross-sectional area times fluid velocity; velocity rises as area decreases.
- Hydraulic power formula
- Power equals pressure times flow rate. In US units, horsepower = (psi × gpm) / 1714; in SI, watts = pascals × cubic meters per second.
- Gauge versus absolute pressure
- Gauge pressure is measured relative to atmospheric pressure, while absolute pressure equals gauge pressure plus atmospheric pressure, about 101.3 kPa.
- Boyle's law
- At constant temperature, the product of pressure and volume of a fixed gas mass is constant: p1V1 = p2V2. Applies to pneumatic compression and expansion.
- Force multiplication ratio
- Output force divided by input force equals the ratio of output piston area to input piston area; greater output force comes with proportionally shorter stroke.
- Cylinder extend force
- Extend force equals system pressure times the full bore area. This is the maximum force a cylinder can produce during extension.
- Cylinder retract force
- Retract force equals pressure times the annulus area, which is bore area minus rod area. It is always less than extend force for the same pressure.
- Relief valve function
- A normally closed, pressure-actuated valve that opens to bypass flow to tank when system pressure exceeds a set value, protecting components from overpressure.
- Tandem center valve
- A directional valve center condition that connects the pressure port to tank while blocking both work ports, allowing the pump to unload at low pressure.
- Meter-out flow control
- A flow control valve placed in the actuator exhaust line to regulate speed; it provides back pressure and stabilizes motion against overrunning loads.
- Accumulator precharge
- The gas charge set in a bladder or piston accumulator before installation; it is typically set below minimum system working pressure to allow usable fluid storage.
- Beta ratio
- The ratio of particles upstream to particles downstream of a filter at a specified micron size; higher beta values indicate better filtration efficiency.
- ISO VG viscosity grade
- A classification of hydraulic fluid viscosity measured at 40 °C; for example, ISO VG 46 has a nominal viscosity of 46 mm²/s.
- Pneumatic force variability
- Because air is compressible, pneumatic cylinder force varies with load and flow; force is not constant through the stroke, unlike hydraulics.
- FRL unit
- An air preparation assembly combining a filter to remove water and particles, a regulator to set pressure, and a lubricator to add oil mist downstream.
- Free air delivery
- The volume of air a compressor delivers referenced to standard atmospheric conditions, used to compare compressor capacity independent of working pressure.
- Meter-out pneumatic control
- Speed control achieved by restricting exhaust air from the cylinder; preferred in pneumatics because it stabilizes motion with overrunning loads.
- Refrigerated air dryer
- A dryer that cools compressed air to condense moisture, achieving pressure dew points around +3 °C, suitable for general industrial use.
- Desiccant air dryer
- A dryer using moisture-absorbing material to reach pressure dew points of −40 °C or lower, used where very dry air is required.
- Rotary screw compressor
- A positive displacement compressor using two intermeshing rotors to compress air continuously; common in industrial plants for steady-duty compressed air supply.
- Shuttle valve function
- A pneumatic logic valve that passes the higher of two input pressures to the output, performing an OR function in pneumatic circuits.
- Double-solenoid valve
- A directional valve with two solenoids and detents that holds its last position when both solenoids are de-energized, providing memory function.
- Proportional valve
- An electrically controlled valve whose flow or pressure output varies proportionally with input current or voltage, offering control between on-off and servo performance.
- LVDT feedback
- A linear variable differential transformer that measures spool or valve position and provides feedback for closed-loop control of proportional and servo valves.
- Sinking versus sourcing
- Sinking (NPN) sensors switch the load to ground; sourcing (PNP) sensors switch the load to positive supply. PLC input type must match the sensor.
- PLC output types
- Relay outputs handle AC and higher currents, transistor outputs switch DC quickly for high cycle rates, and triac outputs switch AC loads.
- Emergency stop category
- Per ISO 13850, an emergency stop is a category 0 (immediate power removal) or category 1 (controlled stop then power removal) action.
- Performance Level
- A rating from ISO 13849-1 (PL a through e) describing the reliability of a safety-related control system against random and systematic failures.
- Valve null offset
- The spool position where flow is zero; null shift causes drift in proportional valve control and requires adjustment or closed-loop correction.
- Three-phase power formula
- For balanced three-phase AC, real power P = √3 × V × I × power factor, where V is line voltage and I is line current.