Engineering Glossary
The essential dictionary for modern engineers. Over 100+ defined terms across Electrical, Mechanical, and Instrumentation disciplines.
The degree of conformity of a measured or calculated value to its actual (true) value.
The calculation of required duct size for a specific air volume and velocity in HVAC systems. Size Duct →
Free Air Delivery (FAD) is the actual volume of air compressed and delivered by a compressor. Calculate FAD →
The number of discrete values an Analog-to-Digital Converter can produce over the range of analog values. Calculate Resolution →
The maximum stress that a material can safely withstand, defined by the yield strength divided by a safety factor. Calculate Stress →
Design of pressure vessels according to ASME Boiler and Pressure Vessel Code standards. Design Vessel →
The maximum current, in amperes, that a conductor or device can carry continuously under specified conditions without exceeding its temperature rating. Calculate Ampacity →
A dangerous release of energy produced by an electrical fault in the air from one phase to another or phase to ground. Arc Flash Calculator →
The vector sum of real power (kW) and reactive power (kVAR) in an AC circuit.
A component of a machine that is responsible for moving and controlling a mechanism or system, usually operated by electric current, hydraulic fluid pressure, or pneumatic pressure.
The range of frequencies within which a system or device operates effectively.
The rate at which information is transferred in a communication channel. Calculate Rate →
The time required to charge a battery based on its capacity and the charging current. Calculate Time →
The estimated operational time of a battery based on load consumption. Estimate Life →
The degree to which a structural element is displaced under a load. Calculate Deflection →
The expected life of a bearing expressed in operating hours or revolutions. Calculate Life →
The percentage of total heat energy available from fuel that is converted to useful steam. Calculate Efficiency →
The rotational force applied to a bolt to create tension and clamp parts together. Calculate Torque →
A measure of the charge stored by the battery, determined by the mass of active material contained in the battery. Size Battery →
States that an increase in the speed of a fluid occurs simultaneously with a decrease in static pressure or a decrease in the fluid's potential energy.
The maximum fault current a busbar can withstand without mechanical damage. Calculate Fault →
A metallic strip or bar, typically housed inside switchgear, panel boards, and busway enclosures for local high current power distribution. Busbar Calculator →
The process of comparing a device or instrument against a standard of known accuracy to detect and correct deviations.
Level measurement using the change in capacitance between two probes. Calculate Level →
Errors in pressure measurement due to temperature changes in liquid-filled capillary lines. Calculate Error →
The cooling capability of a chiller system, often measured in tons. Calculate Capacity →
The energy required to drive a compressor for a given flow and pressure. Calculate Power →
The percentage of the cross-sectional area of a conduit occupied by cables. Calculate Fill →
A measure of how much the valve controls the system flow compared to system resistance. Calculate Authority →
Aerodynamic noise generated by high velocity fluid flow through a valve. Calculate Noise →
The speed at which any metal in a specific environment deteriorates. Calculate Rate →
The formation of vapor cavities in a liquid usually occurring when a liquid is subjected to rapid changes of pressure, often causing damage to pumps.
An automatically operated electrical switch designed to protect an electrical circuit from damage caused by excess current from an overload or short circuit. Size Breaker →
Object or type of material that allows the flow of charge (electric current) in one or more directions.
A type of transformer used to reduce or multiply an alternating current (AC). It produces a current in its secondary which is proportional to the current in its primary. Check Saturation →
An empirical equation that relates the head loss, or pressure loss, due to friction along a given length of pipe to the average velocity of the fluid flow. Calculate Head Loss →
Conversion between differential pressure and flow rate (square root relationship). Convert →
The range through which an input signal can verify without initiating an observable response.
The maximum electric field that a pure material can withstand under ideal conditions without breaking down (i.e., without experiencing failure of its insulating properties).
The ratio of the maximum coincident demand of a system, or part of a system, to the total connected load of the system.
An inadvertent contact between an energized conductor and earth (ground) or equipment frame. Calculate Fault →
Sizing of the protective earth conductor to withstand fault currents. Calculate Size →
The ratio of the useful work performed by a machine or in a process to the total energy expended or heat taken in.
The algebraic difference between the indication and the true value of the measured signal.
The current that flows when a short circuit or other fault occurs in an electrical system. Calculate Fault →
Correction for effects of flow disturbances on meter accuracy. Calculate →
A measure of the efficiency of a valve. It represents the number of US gallons of water at 60°F that will flow through a valve with a 1 psi pressure drop.
The branch of physics concerned with the mechanics of fluids (liquids, gases, and plasmas) and the forces on them.
The ratio of the amplitude of the output signal to the amplitude of the input signal in a system.
Relationships between pressure, volume, and temperature of a gas (Ideal, Boyle's, Charles'). Calculate →
Sizing a generator to meet peak load and starting current requirements. Size Generator →
Pressure relative to the ambient pressure.
The process of creating a low-resistance path to the earth for electrical safety and system stability. Design Grid →
The deformation of the voltage or current waveform caused by nonlinear loads. Calculate THD →
Calculation of thermal energy loss from insulated or uninsulated pipes. Calculate Loss →
The reduction in total head of the fluid as it moves through a system.
Level measurement based on the pressure exerted by a liquid column. Calculate →
The dependence of the state of a system on its history.
The total opposition to current flow in an AC circuit, consisting of resistance and reactance.
A rotating component of a centrifugal pump which transfers energy to the fluid.
The maximal instantaneous input current drawn by an electrical device when first turned on. Calculate Inrush →
Extremely clean, dry air supplied to pneumatic instruments and actuators.
The region between the limits within which a quantity is to be measured. Calculate Range →
A protection technique for safe operation of electrical equipment in hazardous areas. Verify Loop →
The process by which the passage of an electric current through a conductor produces heat.
In flow measurement, it is the number of pulses generated by a flow meter for a volumetric unit of fluid.
A unit of energy equal to 3.6 megajoules. It is commonly used as a billing unit for energy delivered to consumers by electric utilities.
Occurs when a fluid flows in parallel layers.
The frequency at which the inductive and capacitive reactances are equal. Calculate Frequency →
Calculation of number of fixtures required for a given area and lux level. Calculate Lighting →
The closeness of a calibration curve to a specified straight line.
The ratio of the average load over a given period to the maximum demand.
The ratio of mechanical power output to electrical power input of a motor. Calculate Efficiency →
An assembly to control some or all electric motors in a central location.
A circuit conductor that normally carries current back to the source and is connected to ground (earth) at the main panel.
Unwanted electrical signals that produce undesirable effects in the circuits of the control systems in which they occur.
The difference between the suction pressure and the vapor pressure of the fluid, essential to prevent cavitation in pumps.
States that the current through a conductor between two points is directly proportional to the voltage across the two points (V=IR).
States that a pressure change occurring anywhere in a confined incompressible fluid is transmitted throughout the fluid such that the same change occurs everywhere.
Proportional-Integral-Derivative controller. A control loop mechanism employing feedback that is widely used in industrial control systems.
The ratio of the real power flowing to the load to the apparent power in the circuit. Correct PF →
Calculation of fluid volume in a partially filled pipe. Calculate Fill →
Calculation of required pipe wall thickness for pressure. Calculate Thickness →
The average speed of a piston in a reciprocating engine or pump. Calculate Speed →
The difference in pressure between two points of a fluid carrying network. Calculate Drop →
Calculation of wall thickness for pressure vessels. Calculate →
The ratio of the power transferred to the fluid to the power supplied to the pump. Calculate →
Calculation of required pump head and flow. Size Pump →
A graphical representation of a pump's performance, showing the relationship between head and flow rate.
The ratio of the maximum to the minimum controllable flow through a valve.
The process of selecting settings for protection devices to ensure that the device closest to the fault operates first. Coordinate Relays →
A dimensionless quantity used to help predict flow patterns in different fluid flow situations (Laminar vs Turbulent).
A sensor used to measure temperature by correlating the resistance of the RTD element with temperature.
An abnormal connection between two nodes of an electric circuit intended to be at different voltages. Calculate Fault Current →
The depth at which current density falls to 1/e of the surface value. Calculate Depth →
The tendency of an alternating electric current (AC) to become distributed within a conductor such that the current density is largest near the surface of the conductor.
Reduction in sound intensity over distance. Calculate →
Ratio of density of a substance to density of a reference substance. Calculate →
Physical quantity that expresses the internal forces that neighboring particles of a continuous material exert on each other.
Analysis of unbalanced power systems using symmetrical components. Analyze →
The algebraic difference between the upper and lower range values.
A measure of the force that can cause an object to rotate about an axis.
Property of a material to conduct heat. Calculate →
Change in shape, area, volume, and density of matter in response to a change in temperature. Calculate →
A device that converts variations in a physical quantity, such as pressure or brightness, into an electrical signal, or vice versa.
A passive electrical device that transfers electrical energy from one electrical circuit to another, or multiple circuits. Sizing Tool →
Parameters and performance analysis of electrical transmission lines. Analyze Line →
Calculation of steam consumption for turbines. Calculate →
Fluid motion characterized by chaotic changes in pressure and flow velocity.
An electrical apparatus that provides emergency power to a load when the input power source or mains power fails. Size UPS →
A device that measures the distance to an object by using sound waves.
The ratio of the pressure drop across the control valve to the total pressure drop of the system, determining how well the valve controls the flow.
Sizing of vents for tanks and vessels. Size Vent →
The decrease of electrical potential along the path of a current flowing in an electrical circuit. Calculate Drop →
A pressure surge or wave caused when a fluid in motion is forced to stop or change direction suddenly.
The SI unit of power, equivalent to one joule per second.
The stress at which a material begins to deform plastically.
Adjusting the range of a transmitter to account for the difference in height between the transmitter and the process connection.