Electrical Glossary

A         

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  • Active Component  -  Components in a circuit that need external power.
  • Actuator  -  A device used to open, close, or control valves.
  • Alternating Current  -  An electric current that reverses its direction over and over.
  • Alternating Current to Direct Current  -
  • Alternator  -  A device which converts mechanical energy into electrical energy used to maintain a charge in a car battery.
  • American Wire Gauge  -  A measure of wire thickness.
  • Ammeter  -  An instrument for measuring the flow of electrical current in amperes.
  • Amp  -  Amp is a unit of current.
  • Amps to Horsepower  -  Amps (amperes) and horsepower measure different things, but they can be related in the context of electric motors.
  • Amphere  -  A unit of measure for the flow of current in a circuit.
  • Amplifier  -  A device for increasing the power of a signal by taking power from a power supply and controlling the output to match the input signal shape but with a larger amplitude.
  • Amplitude  -  The maximum displacement from the center of the wave.
  • Analog  -  Analog or analogue is a continuous electronic variable signal caring information.
  • Analog Input  -  An analog input is an infinitely variable signal.  In most data acquisition systems this signal is connected to an input amplifier and then to an A/D converter.
  • Analog Output  -  A waveform or control signal generated as a continuous function of the measured parameter.
  • Analog Trigger  -  A trigger that occurs at a user-selected point on an incoming analog signal. Triggering can be set to occur at a specific level on either an increasing or a decreasing signal.
  • Analog Switch  -  A switching device able to rought analog signals.
  • Angular Frequency  -  Measures the angular displacement per unit time.
  • Arcing Time of Fuse  -  After the breaking of a fuse wire there will be arcing between both melted tips of the wire which will be extinguished at the current zero.
  •  Area Classification Drawing  -  Outlines the classifications of areas where flammable liquids, gasses or vapors are handed, processed or stored.  It is created based on input from the Process Flow Diagrams, Piping & Instrumentation Diagrams and the Equipment Location Plan.
  • Armature  -  The part of a machine which receives or delivers active power to the external electrical system.

B         

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  • Background Noise  -  Interfering signals that can cause disturbance affecting a signal that may distort the intended signal.
  • Basic Circuit  -  Has a power source, wires connecting components, and components.
  • Base Load  -  That part of the electricity demand which is continuous and does not vary over a 24-hour period.
  • Base Power  -  Power generated by a utility unit that operates at a very high capacity.
  • Battery  -  A storage device for energy and then discharge.  Batteries can be rated by their energy capacity.
  • Booster  -  A device inserted into a line or cable to increase the voltage.
  • Branch Circuit  -  A portion of the wiring system extending beyond the final overcurrent protective device.
  • Breaker  -  An automatic switching device that disconnect the power to a circut when the current or heat exceeds a certain level for a certain amount of time.
  • Broadband  -  A transmission medium with enough bandwith to cary multiple channels, data, video and voice at the same time.
  • Brush  -  A sliding electrical contact, usually rotating.
  • Buffer  -  An autio signal device.
  • Burst Mode  -  A high-speed data transfer in which the address of the data is sent followed by back-to-back data words while a physical signal is asserted.
  • Bus  -  The group of conductors that interconnect individual circuitry in a computer.  Typically, a bus is the expansion vehicle to which I/O or other devices are connected.
  • Bus Master  -  A type of a plug-in board or controller with the ability to read and write devices on the computer bus, without using the host CPU.

C         

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  • Capacitor  -  Behaves as a charge storage device.  Holds an electric charge when voltage is applied across it and gives up the stored charge when required.
  • Capacitance  -  The ability of a system to store electrical charge.  The capacitance of a system depends on its physical characteristics and the arrangement of its components.  In other terms, capacitance quantifies how much charge a capacitor can store per unit of voltage.
  • Capacitive Reactance  -  The opposition to holding an electric charge.  It refers to the opposition or resistance that a capacitor presents to the flow of alternating current, just like resistance opposes the flow of direct current.
  • Capacitor  -  A passive electronic component that stores electrical energy in an electric field.  It consists of two conductive plates separated by a non-conductive insulating material called a dielectric.  When voltage is applied across the plates, electric charge accumulates on them, creating an electric field between them.  This stored charge creates a potential difference (voltage) across the capacitor.
  • Cartridge Fuse  -  The fuse wire is enclosed in a transparent glass bulge or tube completely sealed.
  • Cell  -  Cells generate energy through a thermal process, chemical or optical.
  • Coal Energy  -   The process of generating electricity by burning coal, a fossil fuel that has been used for centuries as a primary energy source.
  • Cogging Torque  -  Magnetic interaction between stator and rotor resulting in undesired machine operation such as jerkiness.
  • Coil  -  Set of series connected turns.
  • Circular Frequency  -  Measures the angular displacement per unit time.
  • Cold Junction  -  The end of thermocouple that is kept at a constant temperature in order to provide a reference point.
  • Commutation  -  Change-over switching in a periodic and automatic manner without interruption of the electric current.
  • Commutator  -  An assembly of insulated conducting segments connected to the rotating armature winding.
  • Concentric Winding  -  A distributed winding in which the individual coils of each phase group per pole are concentric and have different coil spans.
  • Conductance  -  The measure of ease that the material offers in the path of current, it is the opposite of resistance.  The higher the conductance, the better the material conducts electricity.
  • Conductivity  -  A property that measures a material's ability to conduct an electric current.  Electric conductivity is determined by the presence of charged particles, such as electrons or ions, that are free to move within the material. 
  • Conductor  -  A material through which heat passes and allows the free flow of electric charge.
  • Contacts  -  Components
  • Control Narrative  -  A system control philosophy is a document that is used to describe general principles of operation.  Variables such as alarm set points or shutdown values are usually described in the control narrative.  A control philosophy solidifies basic definitions, principles and processes during the design and implementation of a process.
  • Conventional Current Flow  - This is the flow of a positive charge around a circuit (positive (+) to negative (-)), which is the opposite direction to the flow of electrons.
  • Coulomb's Constant  -  In vacuum, Coulomb's constant determines the strength of the electrostatic force between two stationary charged particles.  It is analogous to the gravitational constant in Newton's law of universal gravitation, which determines the strength of the gravitational force between two masses.
  • Coulomb's Law  -  The magnitude of the electrostatic force between two electric charges.  In case of more than two electric charges, the superposition principle in addition to coulomb’s law is applied to calculate the net electronic force acting on any one charge.
  • Core Loss  -  The electrical losses in a machine caused by the magnetization of the core iron.
  • Critical Speed  -  The rotating speed at which resonance occurs.
  • Current Density  -  The amount of electric current flowing through a unit area of a conductor.  It is a measure of the current per unit area cross-section and provides information about the distribution of electric current within a material.
  • Current Rating of Fuse  -  The maximum value of current due to which fuse does not melt.
  • Current Transformer  -  Used to supply information for measuring power flows and the electrical inputs for the operation of protective relays associated with the transmission and distribution circuits or for power transformers.

D         

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  • Daniell Cell  -  A copper vessel containing copper sulfate solution.
  • Data Recorder  -  Another name for a data logger, though data recorders are typically higher performance and offer higher sample rates than a typical data logger.
  • Data Storing  -  The process of collecting and storing data over a period of time in order to analyze specific trends or record the state of a system at different points in time. Data is typically collected from sensors, instruments, or other sources and can be stored in a variety of formats, such as text files, databases, or cloud data storage services.
  • DC Motor Armature Voltage  -  The voltage applied across the armature (the rotating part) of a direct current (DC) motor.  The armature is typically a coil of wire wound around a core that sits within a magnetic field created by the motor's field windings or permanent magnets.  This voltage is used to determining the motor's performance, including its speed and torque.
  • Deadband  -  The value of measurement between when a switch actuates and deactuates.
  • Dielectric  -  A substance or material that is an electrical insulator, meaning it does not conduct electricity easily.  Dielectrics are characterized by their ability to support an electric field and store electric energy in the form of an electric field when subjected to an electric field.
  • Dielectric Constant  -  The measure of a substance to an electric field expressed as the ratio of its electric displacement to the applied field strength.
  • Dielectric Strength  -  The force required to drive an electric current through a definite thickness of the material.
  • Differential Input  -  An analog input consisting of two terminals, both of which are isolated from computer ground, whose difference is measured.
  • Diode  -  A device allowing the current to flow as a one-way switch only and restricting the current from flowing in the opposite direction.  Diodes allow the current to flow when the anode is positive and the cathode is negative.
  • Diode Bridge  -  A combination of four diodes that are connected togeather
  • Diode Types  -  Avalanche diode, laser diode, light emitting diode, photodiode, PIN diode, PN junction diode, schottky diode, tunnel diode, varactor diode, and zener diode.
  • Direct Current  -  An electrical current that flows in one direction through a conductor.  Unlike alternating current (AC), which periodically reverses direction, DC flows consistently in one direction.
  • Distribution Bus  -  A steel structure of switches used to route power out of a substation.
  • Distribution Transformer  -  Reduces the voltage of the primary circuit to the voltage required by customers.
  • Discharge  -  The conversion of chemical energy of a battery into electric energy.
  • Double Pole  -  A switch device that opens, closes, or changes connection of two conductors in an electrical circuit.
  • Double Throw  -  A switch that opens, closes, or completes a circuit in both extreme positions of its actuator.
  • Double Pole Double Throw Switch  -  Two separate switches that operate simultaneously, each with a normally open and a normally closed contact and a common connection.
  • Drift  -  A gradual change in an element over time when the process conditions are constant.
  • Dry Circuit  -  A low current circuit that does not generate enough power to generate an arc.
  • Dump Circuit  -  A way to remotely trip a circuit breaker without there having to be a current overload.
  • Duplex Winding  -  An armature winding in which the coil ends are connected to alternate commutator segments.
  • Dust Proof  -  Constructed or protected so that dust will not interfere with its operation.

E         

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  • Eddy Currents  -  Localized magnetically induced currents in an iron core.
  • Electric Charge  -  A basic characteristic of matter that is based on the balance of protons (positive charge) and electrons (negative charge).  Causes objects to feel an attraction or repulsive force toward one another.
  • Electric Circuit  -  Combine components, wires, and electricity in a closed loop through which electricity can flow to accomplish some functions.  The flow of current is from positive to negative.
  • Electric Conductivity  -  The amount of current that a material can conduct.
  • Elecrtic Current  -  The rate of flow of electricity passing through a circuit per unit of time., measured in amperes.
  • Electric Current Density  -  The amount of electric current flow through a unit value of the area cross-section.
  • Electric Field  -  An invisible space around a charged particle where an electric force is exerted on other charged particles.
  • Electric Field Intensity  -  The space around an electrically charge body in which a charge experiences a force of attraction or repulsion.
  • Electric Flux  -  The quantity of electric field passing through a given surface.  It represents the total number of electric field lines passing through a surface and provides a measure of the strength of the electric field through that surface.
  • Electric Grid  -  An intergrated system of electricity distribution normally over a large area.
  • Electric Potential  -  Difference in the electric charge between two points in a circuit, it's called voltage.
  • Electric Potential Energy  -  The energy or force that is required to move a charge in resistance to an electric field.
  • Electric Power  -  The rate of doing work and is measured by the amount of foot pounds of work done in a particular unit of time.
  • Electric Resistance  -  A measure of how much an object or substance opposes the flow of electric current through it.  In order to overcome the resistance and get the current to flow a higher voltage will be required.
  • Electric Transient  -  A momentary disturbance of energy induced upon power, data, or communication lines, such as turning off and on of a circuit.
  • Electric Voltage  -  The amount of work or pressure (one ampere of current in one ohm of resistance) required to move an electric charge from one point to another is called voltage.
  • Electrolyte  -  A compound that produces ions when dissolved in water and having either a positive of negative charge.
  • Electromotive Force  -  The force which causes current to flow in a circuit.
  • Electron  -  A subatomic particle found in all atoms, electrons carry electricity by flowing from one atom to the next in a conductive material.
  • Electron Flow  -  The opposite direction (negative (-) to positive (+)) from the conventional current flow which is (positive (+) to negative (-)).
  • Electromagnetic Energy  -  The energy carried by electromagnetic waves.  These waves are composed of electric and magnetic fields oscillating perpendicular to each other and traveling through space.
  • Electromagnetic Relay  -  A switch that is controlled by an electrical circuit using the relay coil to physically move a mechanical switch.
  • Electromagnetism  -  A branch of physics that deals with the motion of electric currents and magnetic fields.
  • Electromotive Force  -  The energy provided by a source of electrical power, such as a battery or a generator.  It is not actually a "force" in the mechanical sense but rather a measure of the potential difference (voltage) generated by a power source when no current flows through the circuit.
  • Electron Flow  -  The opposite direction (negative (-) to positive (+)) from the conventional current flow which is (positive (+) to negative (-)).
  • Electrostatic  -  Related to static electricity or electricity at rest.  A constant intensity electric charge.
  • Energy  -  It is never created or destroyed First Law of Thermodynamics, but it can be transferred from one object to another.
  • Explosion Proof  -  Designed and constructed to withstand and internal explosion without creating an external explosion or fire.

F         

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  • Field  -  An invisible space around a charged particle where an electric force is exerted on other charged particles.
  • First Law of Thermodynamics  -  This means that the total amount of energy in the universe is constant and that it can neither be created or destroyed.  This law states that for every gain in some type of energy will result in the loss in some other form.
  • Flammable Liquid  -  Any liquid having a flash point below 100 deg F and having a vapor pressure not to excede an absolute pressure of 40 psi.
  • Float Switch  -  An electrical switch operated by a fliud flow.
  • Flux  -  How much of something goes through a given area.
  • Flux vs Flux Density  -
  • Forward Biased Diode  -  The external voltage which is applied across the PN-diode for reducing the potential barrier to constitute the easy flow of current.
  • Frequency  -  The number of occurrences of a repeating event or cycle within a specified unit of time.
  • Frequency Band  -  A particular range of frequencies that form part of a larger continuous series of frequencies.
  • Full Load Speed  - Machine speed at rated load.
  • Fuse  -  An safety device that removes electrical current from a circuit when the current is two high.
  • Fuse Law  -  The current carring capacity of a fuse wire.
  • Fuse Wire  -  Can carry the normal current without excessive load, but with to much load it rapidly heats up and melts.
  • Fuse Wire Materials  -  Mainly aluminum, antimony, copper, lead, silver, tin, and zinc.
  • Fusing Factor  -  The ratio of minimum fusing current and current rating of the fuse.

G         

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  • Galvanic Separation  -  Instead of using a physical connection to activate the relay, the connection will have to be made using LED or infrared light.
  • Generator  -  A mechanical device that produces electrical energy from mechanical energy.
  • Gigawatt  -  One billion watts.  One million kilowatts.  One thousand megawatts.
  • Grid  -  A system of power lines and generators.
  • Grounded Conductor  -  A system or circuit conductor that is intentionally grounded, using gray or white in color.
  • Grounding  -  The removing of excess change on an object by transfering electrical charges from a short circuit between this object and another larger object.
  • Grounding Conductor  -  Used to connect metal equipment enclosures amd/or the system grounding conductor to a grounding electrode.
  • Ground Resistance  -  The resistance encountered by an electrical current when it travels from an electrical system or device to the Earth (ground) through a grounding electrode or system. 
  • Grounding Transformer  -  Intended primarily to provide a neutral point for grounding.
  • Ground Fault  -  When an underground conductor comes in contact with anything that is grounded.
  • Ground Fault Circuit Interrupter  -  A device for the protection of personal that functions to de-energize a curcuit.

H         

I         

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  • Ignition Coil  -  A device used to supply DC voltage to the spark plugs.
  • Impedance  -  The total effects of a circuit that opposes the flow of an ac current consisting of capacitance, inductance, and resistance.
  • Inductance  -  The measure of an electric conductor or circuit by which an electromotive force is induced in it.
  • Induction Motor  -  The power is transfered to the rotor winding by the stator through induction.  The induction motor always runs at a speed lower than synchronous speed.
  • Inductive Load  -  Current passing through wound or coiled wire creates a magnetic field that, in turn, produces mechanical work.
  • Inductive Reactance  -  The opposition that an inductor presents to the flow of alternating current (AC).  In an AC circuit, the current is constantly changing direction, oscillating back and forth.  When the current through an inductor changes, it induces a voltage in the coil according to Faraday's law of electromagnetic induction.
  • Inductive Reactance  -  The current flow of an alternating current in an inductor is reduced.
  • Inductor  -  An electrical component that stores energy in a magnetic field when an electric current passes through it and releasing this stored energy back into the circuit when the current changes.
  • Inductor Voltage Spike  -  The sharp rise in voltage that occurs across an inductor when the current flowing through it is suddenly interrupted or changed rapidly.
  • Instantaneous Voltage  -  The voltage of an electrical system at a specific point in time.  In alternating current (AC) systems, voltage continuously varies over time, oscillating between positive and negative values.
  • Insulator  -  Opposes the flow of electricity and keep us safe.
  • Integral Control  -  A method of changing the output of a controller by an amount proportional to the error and the duration of that error.
  • Invertor  -  An electrical which is designed to convert direct current into alternating current.

J         

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  • Joule’s Law  -  The amount of heat (energy) delivered to something.
  • Jumper  -  A short length of a conductor used to make a connection between terminals.

K         

L         

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  • Led  -  Emits energy in the form of light instead of energy.
  • Linearity  -  Ability of a measuring instrument to provide an indication having a linear relationship with a defined quantity other than an influence quantity.
  • Load  -  A device that consumes electrical power and is connected to a source of electricity.
  • Lorentz Force  -  Is when you place a moving charged particle in a magnetic field.
  • Low Voltage  -  Defined as 50 volts or less.

M         

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  • Magnetic Field  -  Magnetic fields never cross, never start or stop, where the field is strongest lines bunch togeather and can be seen clearly seen in the real world.
  • Magnetic Flux  -  The number of magnetic field lines passing through a given closed surface.
  • Magnetic Permeability  -  The ability of a material to respond to how much electromagnetic flux it can support to pass through itself within an applied electromagnetic field.
  • Maximum Power Transfer Theorem  -  The maximum power transfer occurs when the load resistance equals the Thevenin or Nortonresistance of the network providing the power.
  • Magnetic Switch  -  Depending on the switch configuration for on and off, the switch is activated when the magnetic field is detected.
  • Manual Reset  -  A control that must have human input before it will return to its normal state from an alarm state.
  • Mechanical Energy  -  The sum of the change in kinetic energy and potential energy generating from the force of gravity, external forces or the movement released in machine movement.
  • Mechanical Relay  -  Has moving parts.
  • Melting Time of Fuse  -  The time taken by a fuse wire to get broken by melting.
  • Millman's Theorem  -  Used to simplify complex circuits containing multiple voltage sources.  Millman's theorem states that in a circuit composed of multiple voltage sources in parallel with their respective resistances, you can find the voltage across a particular branch by treating each voltage source resistance combination as a current source resistance combination, calculating the currents, and then finding the equivalent voltage.
  • Minimum Fuse Current  -  The minimum value of current due to which fuse ments.  Can carry the normal current without excessive load, but with to much load it rapidly heats up and melts.
  • Maximum Surge Pressure  -  Safe pressure for the switch housing but which may damage the mechanism by continuous or repetitive application.
  • Motor  -  Converts the electric energy to mechanical energy.
  • Motor Efficiency  -  The ratio of shaft power power out and electric power input of a motor.
  • Mush Coil  -  A wound coil where the conductors occupy random positions in the slot.
  • Mutual Inductance  -  The inductance of a coil due to current in another nearby coil.

N         

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  • Normally Closed  -  The circuit is closed when the switch is not open.
  • Normally Open  -  The circuit is open when the switch is not operated.
  • Norton's Theorem  -  A principle in electrical engineering and circuit theory that simplifies the analysis of complex electrical circuits.  It states that any linear electrical network with voltage and current sources and resistances can be replaced at a pair of terminals with an equivalent current source IN (called the Norton current) in parallel with an equivalent resistance  (called the Norton resistance).
  • Null Switch  -  A floating contact switch with a zone of no contact.  Often used to operate reversible motors.

O         

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  • Off-peak Rate  -  The rate of cost for power used during off-peak periods.
  • Ohm  -  A unit of resistance.
  • Ohm's Law  -  The relationships between power, voltage, current, and resistance.
  • Ohm's Law Pie Chart  -
  • Operating Time of Fuse  -  The time gap between the instant when the overall current starts to flow through the fuse and the instant when the arc in the fuse finally gets extinguished.
  • Operational Amplifier  -  A voltage amplifier with very high gain.
  • Overload Protection  -  Protect the motor by monitoring the current flow in the circuit.
  • Overload Protection Relay  -  These relays have a trip class rating for different applications.  This is usually sufficient time for the motor to reach full speed.
  • Overload Relay Tripping  -  The time taken by the relay to open in an overload condition.

P         

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  • Parallel and Series Circuit  -  Two different configurations in which electrical components can be connected within a circuit.
  • Parrallel Circuit  -  The parts are arranged in branches each going their own way.
  • Parrallel Resistor  -  Resistors are arranged in branches each going their own way.
  • Passive Component  -  Components that do not require any external power.
  • Permeability  -  The ability of a material to respond to how much electromagnetic flux it can support to pass through itself within an applied electromagnetic field.
  • Permittivity  -  The ability of a substance to store electrical energy in, and release energy from, an electric field.
  • Phase Constant  -  How much displacement a wave is from an equilibrium or zero position.
  • Port  -  A connection or a jack provided on a computer to connect external or peripheral devices to the computer.  It is a virtual point where network connections start and end.  Ports are software based and managed by a computer's operating system.  Each port is associated with a specific process or service.
  • Potential Energy  -  The possessed energy by a body due to its relative position in a gravitational field
  • Power  -  The rate of doing work (the amount of foot pounds of work done in a particular unit of time) required and the number of electrons passing through the circuit per unit time.
  • Power Density  -  The ratio of the power available from a battery to its mass or volume.
  • Power Factor  -  The ratio between the amount of consumed power and the amount of absorbed or returned power.
  • Preset Resistor  -  The resistance is adjusted with rotary control pressure on top with a screw driver.
  • Primary Cell  -  A dry cell and not a rechargeable cell.  A chemical reaction between electrodes and electrolites causing a permanent change.
  • Proportional Control  -  A method of changing the output of a controller by an amount proportional to the error.
  • Prospective Current in Fuse  -  The value of current which would flow through the fuse immediately after a short circiut occures in the network.

Q         

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  • Quick Disconnect  -  A type of connector that permits rapid locking and unlocking of two connector halves.

R         

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  • Radial Frequency  -  Measures the angular displacement per unit time.
  • Random Wound Coil  -  The conductors occupy random positions in the slot.
  • Rated Flow  -  The maximum flow that the power supply system is capable of maintaining at a specific operating pressure.
  • Rated Voltage  -  The maximum voltage at which an electric component can operate for extended periods without undue degradation of safety hazard.
  • Rectifier  -  An electrical device that convert alternating current (AC) to direct current (DC).
  • Relay  -  A type of electric switch that is operated by an electromagnet which charges over the switching when current is applied to the coil.  Types of relays are electromagnetic relay, solid state relay, thermal relay, and time relay.
  • Resistivity  -  A property of materials that describes their inherent resistance to the flow of electric current.  It is a measure of how strongly a material opposes the flow of electrical current through it.
  • Resistor  -  Anything that reduces or restricts the movement of electrical current through it.
  • Resistors in Parallel  -  No matter how many resistors in parallel there are, two or ten, just specify the number of resistors and the resistance value for each one.
  • Resistors in Series  -  No matter how many resistors in series there are, two or ten, just specify the number of resistors and the resistance value for each one.
  • Reverse Biased Diode  -  The external voltage which is applied to the PN junction for strengthening the potential barrier and prevents the flow of current.
  • Right-hand Rule  -  When current is flowing through a wire, the magnetic field rotates around the wire.  The direction of the current determines the direction of the magnetic field.
  • Rotor  -  The rotating element of an induction motor.

S         

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  • Secondary Cell  -  A wet cell and is a rechargable cell.  Generates a current through a secondary cell in the opposite direction of the first cell.
  • Self Inductance  -  The inductance of a coil or inductor due to its own current.
  • Semiconductor  -  A type of material that has an electronic resistance between the metal and the resistance insulator.
  • Series Circuit  -  The parts are connected end to end.
  • Series Resistors  -  Resistors connected end to end.
  • Service Conductor  -  Supply conductors that extend from the street main or transformer to the service equipment of the premises being supplied.
  • Service  -  The equipment and conductors that transmit electricity from the utility supply system to the building being served.
  • Service Drop  -  Run of cables from the power companies aboveground lines to the point of connection to the customer's premises.
  • Service Equipment  -  The necessary equipment, usually a circuit breaker or switch and fuses and their accessories.
  • Service Point  -  The point of connection between the facilities of the service utility and the premises wiring.
  • Shockley Diode  -  Has fast switching operation.
  • Short Circuit  -  A low resistance connection unintentionally made between points of an electrical circuit which may resullt in current flow far above normal levels.
  • Shunt  -  Also called a shunt resistor, is a conductor joining two points in a circuit used to limit the speed of the current.
  • Single-phase  -  An ac electric system or load consisting of at least one pair of conductors energized by a single alternating voltage.
  • Skew  -  Non parallel stator and rotor slot alignment.
  • Slip  -  The difference between the synchronous speed and the actual speed of a rotor expressed as per unit or as a percentage of the synchronous speed.
  • Solar Constant  -  The strength of the sun.
  • Solar Cell Efficiency  -  The ability of a solar cell to convert sunlight into usable electrical energy.  It is typically expressed as a percentage and represents the ratio of the electrical power output of the solar cell to the total power of sunlight hitting the cell. 
  • Solar Energy  -  Energy that comes from the sun and is harnessed using various technologies to generate electricity, heat, or to support other processes.  It is a renewable and sustainable source of energy, meaning it can be replenished naturally and doesn't deplete resources.
  • Solenoid  -  A device made of a coil of wire.  When current is introduced a magnetic field is formed around the coil (electrical energy) and the plunger is pulled in (mechanical work).  When the current is removed the plunger is released.
  • Solid State Relay  -  Has no moving parts and relys on either infra-red light emitting diodes or LED couplers to operate.
  • Span Temperature Coefficient  -  The maximum amount the span reading could change at any point within the compensated temperature range. This error is typically expressed as a percentage of full-scale output of reading.
  • Spent Fuel  -  Fuel assemblies removed from a reactor after use.
  • Static Electricity  -  The build up of an electric charge on the surface of an object.
  • Stator  -  The stationary element of an induction motor.
  • Substitution Theorem  -  A principle in electrical circuits analysis, particularly in the study of linear circuits.  It states that any element in a linear electric network can be substituted by a combination of independent voltage or current sources and their associated resistances, without changing the behavior of the rest of the network with respect to any pair of terminals.
  • Superposition Principle  -  A basic concept in physics and engineering, particularly in the fields of wave theory, quantum mechanics, and linear systems.  The principle states that, in a linear system, the net response at a given place and time caused by two or more stimuli is the sum of the responses that would have been caused by each stimulus individually.
  • Surge Capacity  -  The ability of an electrical supply to tolerate a momentary current surge or inrush imposed by the starting of motors or the energizing of transformers.
  • Switch  -  A device that opens and closes electrical circuit.
  • Synchronous Speed  -  In rotating electric machines such as generators and motors, the magnetic field rotates at a constant speed produced by the alternating machine.

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  • Tellegen's Theorem  -  A tool for analyzing electrical circuits and networks.  Tellegen's theorem stated for any linear or nonlinear, passive or active network, the summation of the power at each element in the network is zero, provided that Kirchhoff's current law (KCL) and Kirchhoff's voltage law(KVL) are satisfied.  In other words, the algebraic sum of power supplied or absorbed by all elements in the network is always zero.
  • Temperature Coefficient of Resistance  -  The change in resistance with applied voltage.
  • Temperature Compensation  -  The correction for the influence of temperature on a measurement.
  • Thermal Insulator  -  Does not conduct heat readily and is used for either heat conservation or personnel protection.
  • Thermal Overload Relay  -  This device works on the heat produced by the excessive overload current.
  • Thevenin's Theorem  -  A theorem in electrical network theory.  This theorem states that any linear electrical network with voltage and current sources and resistances can be replaced by an equivalent circuit consisting of a single voltage source in series with a single resistor, called the Thevenin resistance.
  • Three-phase  -  An ac electric system or load consisting of three conductors energized by alternating voltage that are out of phase by one third of a cycle.
  • Tidal Water Energy  -  A form of renewable energy generated by harnessing the movement of tides.  Tidal energy is considered a predictable and reliable source of power, unlike other renewable sources like wind and solar, which can be more variable.
  • Time Delay Relay  -  A relay that when the input action signal is added, the output circuit needs to pass through the specified accurate time to produce jump charge.
  • Transformer  -  A device that uses electromagnetism to convert one current to another current.
  • Transformer Vault  -  An underground structure in which power transformers, circuit breakers, voltage regulators, and etc. are housed.
  • Transducer  -  A voltage output device used for convert energy to another form.
  • Transmitter  -  A current output device used for communication electronic signals over a distance.
  • Transmission Bus  -  Steel structure arrays of switches used to route power in a substation.
  • Transmission Line  -  Transmits high-voltage electricity from the generation source or substation to another substation in the electric distribution system.
  • Triac  -  An electrical componeht approximately equal to two silicon-controlled rectifiers joined in inverse parallel and their gates connect togeather.
  • Trickle Charge  -  Charging at a low rate.
  • Tripping Class  -  Defines the starting time at a specific current before tripping occures.  The number in the trip class is the total number of seconds that the motor is allowed to overload before the circuit trips.
  • Tuner  -  A circuit that can pick signals from a frequency from a group of signals of different frequencies.
  • Turndown Ratio  -  The ratio of the maximum to minimum measurable value that can still produce full-scale output.

U

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  • Varactor Diode  -  The capacitance varies according to the applied input voltage.
  • Variable Capacitor  -  Used in tuning the circuit to a required frequency.
  • Variable Indicator  -  Allows the value of the inductance to be changed.
  • Volt -  A unit of electrical pressure.
  • Voltage Coefficient of Resistance  -  A measure of how the electrical resistance of a material changes with variations in voltage.  It quantifies the percentage change in resistance per unit change in voltage.
  • Voltage Divider  -  An electronic circuit arrangement that divides a given voltage into smaller fractions using a combination of resistors.  The voltage divider circuit consists of two or more resistors connected in series between a voltage source and ground.  The output voltage is taken from the connection point between the resistors.
  • Voltage Drop  -  The electricity between the meter and where it is to be used.  It is basically impossible to have no voltage loss.  Voltage drop is the decrease in voltage along a conductor or a circuit element as current flows through it.  It is a result of the resistance of the conductor or the circuit element, which causes energy to be dissipated in the form of heat.
  • Voltage Output  -  Output in voltage form, typically proportional to the applied measurement.
  • Voltage Rating  -  The maximum voltage at which a cable or insulated conductor can be safetly maintained during continuous use in a normal manner.

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  • Wavelength  -  The distance between the crests of a wave.  Each wave has a shape and length.  The wavelength of a wave is the distance between two consecutive points that are in phase (two successive peaks or troughs), and it is inversely proportional to the frequency of the wave.
  • Wavelength Velocity  -
  • Wave Winding  -  Armature winding with each coil of 2 conductors placed in slots 90° apart, connections made in segments approximately 180° apart on the commutator.
  • Winding  -  All of the coils of a generator.

X

Y

Z

  • Zero Temperature Coefficient  -  The maximum amount the output reading at zero pressure might deviate over the compensated temperature range.  This error is typically expressed as a percentage of full-scale output of reading.

 

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