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]]>The sum of the instantaneous voltages in a half cycle wave shape divided by the number of instantaneous voltages. In a sine wave, it is equal to 0.637 times the peak voltage.

Analog meters are a multifunctional multimeter that operates based on electrical mechanical movement.

A transformer with a single electric winding, which can be used as a step-down or step-up device; a transformer characterized by no electrical isolation between primary and secondary.

The reciprocal of a circuit’s impedance, measured in Siemens.

The atom is made up of subatomic particles, the most important of which are the electrons and protons.

An Ammeter is a device used for the measurement of current in amperes (or even in smaller units like mA or μA).

The system of notation for measuring the size of conductors or wires.

An electric current that periodically changes its direction, usually many times per second.

It is the power transferred from the machine stator to the rotor across the air gap.

ACSR is a composite conductor which is made up of an amalgamation of aluminum wires surrounding the steel.

The magnetic ﬁeld strength, at any point in the neighborhood of a circuit in which there is a current i, is equal to the vector sum of the contributions from all the differential elements of the circuit. The contribution dH, caused by a current i in an element ds at a distance r from a point P is given by

$d\text{H}=\frac{r[\text{r}*\text{ds}]}{{{r}^{2}}}$

The order in which the successive members of the set reach their positive maximum values. Phase a is followed by phase b and then by phase c.

The product of the root-mean-square voltage and the root-mean-square current.

The winding in which alternating voltage is generated by virtue of relative motion with respect to a magnetic ﬂux field.

The time average of the instantaneous power; the average being taken over one period.

A signal with a varying voltage or current. A continuous set of values.

A term used to describe test equipment where the test equipment automatically adjusts the range to display the correct readout. For example, if you are measuring a voltage under 2 volts, you would select read voltage and the meter would automatically read the voltage and display the value.

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]]>In a parallel circuit, each current path is a Branch.

A resonant circuit that is tuned to pass a single band of frequencies and to attenuate all other signals.

A network that attenuates a single band of frequencies and allows those on either side to pass; sometimes called band-stop filter.

A set of phasor currents (or phasor voltages) that have equal magnitudes and are separated from each other by equal phase angles.

A test applied to an induction motor, in which the rotor is blocked so it cannot rotate.

An assembly of two or more conductors used as a single conductor and employing spacers to maintain a predetermined conﬁguration. The individual conductors of this assembly are called sub-conductors.

A solid conductor, or metallic strip, that serves as a common connection for two or more circuits. Generally, currents from incoming feeders accumulate on it and then further distribute to the outgoing feeders.

A matrix whose elements have the dimension of admittance and, when multiplied by the vector of bus voltages, gives the vector of bus currents.

A voltage source that uses chemical energy to create electrical energy.

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]]>The property of a circuit that permits the storage of an electric charge when a difference of voltage is applied.

Electric current is the rate of flow of charge in a conductor.

A resistor inserted into an electric circuit to limit the current to some pre-established value.

A two-terminal circuit element with an output current essentially independent of the voltage between its terminals and characterized by a high internal resistance.

A capacitor is a passive device which stores energy in an electric field and opposes a change in voltage.

An electric circuit is a combination of various electric circuit elements to form a closed path or loop.

Opposition to the flow of an alternating current by the capacitance of a circuit; equal to 1/2πfC and measured in ohms.

A continuous path from the voltage source through interconnecting wiring and device(s) and back to the source.

When the time variable t takes its values from the set of real numbers, the system is said to be a continuous time system or and an analog system.

Conductance is defined as the reciprocal of a resistance. The unit of conductance is mho or Siemens.

In a closed loop control system, the controller is fed by a signal that is the difference between the reference input signal and the modified output.

Electric charge is a basic property of atomic particles of matter, measured in coulombs C.

Materials with many free electrons that facilitate the passage of electric current.

A transmission line in which one conductor is concentric to another and separated by a continuous solid dielectric spacer.

A luminous discharge of electricity caused by ionization of the air around a conductor carrying a high potential.

An automatically operated electrical device which is designed to safeguard a circuit from damage caused by unexpected excessive electric current, generally consequent of an overloading or electric short circuit. The circuit breaker’s main purpose is to disrupt current flow after a fault in an electric system is sensed.

A unit of area equal to π/ 4 of a square mil (0.7854 square mil). The cross-sectional area of a circle in circular mils is therefore equal to the square of its diameter in mils.

A function associated with the ﬁeld energy function such that the sum of the energy and co-energy functions is equal to the sum of the products of the flux linkage of a coil multiplied by the corresponding current flowing through it.

The product of the phasor voltage multiplied by the complex conjugate of the phasor current.

The power dissipated in a magnetic core subjected to a time-varying magnetizing force.

The effective electromotive force within the system that opposes the passage of current in a specified direction

The value of field circuit resistance of a DC Shunt Generator above which the generator fails to trip.

A parallel circuit used to split the current amongst several branches

Central Processing Unit. A microprocessor system that contains the system memory and is the PLC’s decision-making unit.

The positive and negative alternations of a wave.

A specialized piece of electrical test equipment for measuring large currents. These currents are frequently over one amp and higher.

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]]>When the time variable t takes on the discrete values t=kT, k=…,-2,-1, 0, 1, 2… the system is said to be discrete – time system.

Voltage or current source whose value linearly depends upon the value of voltage or current of other elements in the circuit.

A digital multimeter (DMM) is a multifunctional meter that displays its electrical quantitative values on an LCD screen.

A logarithmic unit for expressing the difference between two sound, power, voltage or current levels.

Current that continues to flow in the same direction is called direct current and remains constant.

The material between two plates of a capacitor is non-conducting or insulating. This insulating material is called dielectric. An example of some dielectrics is air, ceramic, Formica and Teflon.

The dielectric strength of a material is a measure of how much voltage it can withstand, before breaking down.

Acicular (needle-shaped), microscopic crystals containing a very large number of atoms whose spinning electrons result in a net magnetic effect in a particular direction.

An electromechanical conversion device whose armature voltage and current, as well as field voltage and excitation current, are all DC.

The power Converted from electrical to mechanical or from mechanical to electrical.

A Square matrix in which all the elements, not in the principal diagonal, are equal to zero; that is, a_{ij}=0 for all i≠ j.

The ratio of the sustained fundamental component of armature voltage that is produced by the total direct-axis ﬂux due to direct-axis armature current to the fundamental component of this current, the machine running at rated speed.

A meter used to measure electrical quantities that can measure different electrical quantities such as voltage and amperage and displays the reading as numbers or digitally.

A set of electronics that gives precise control over electric motors including speed and direction.

Hardware that is capable of receiving only one input consisting of either a high or low.

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]]>An electromagnet is composed of a coil of wire wound around a core of a soft iron.

A negatively charged subatomic particle with much less mass than a proton but with a charge equal and opposite to the charge of a proton.

Energy is the capacity to get work done, measured in Joules (J).

The arrangements of electrons into definite shells around the nucleus of an atom.

The field of force surrounding any charged body.

The distribution of total generation requirements among alternative sources for optimum system economy, with due consideration of both Incremental generating costs and incremental transmission losses.

The ratio of the useful power output to the total power input.

Electric power used by devices connected to an electrical generating system.

A voltage produced in a closed path or circuit by the relative motion of the circuit or its parts with respect to magnetic ﬂux.

The conductor radius r multiplied by e^{-1/4} (i.e., re^{-1/4}) where e is the base of the natural logarithm.

A group of components that use voltage, current, and resistance to perform a function in a closed path.

It is the ratio of output power (POUT) to the input power (PIN).

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]]>The SI unit of capacitance is Farad, named in honor of the English physicist and chemist Michael Faraday. The unit symbol for the farad is F.

A protective device containing a special wire that melts when excessive current passes through it, thereby opening the circuit.

A selective network of inductors, resistors, and capacitors that offer little opposition to certain frequencies, while attenuating or blocking other frequencies.

The electromotive force induced is proportional to the time rate of change of magnetic ﬂux linked with the circuit.

An iterative technique for solving the nonlinear power ﬂow equations by separately and alternatively solving for the voltage angles and voltage magnitudes.

A physical condition that causes a device, a component, or an element to fail to perform in a required manner, for example, a short circuit, a broken Wire, or an intermittent connection.

The energy stored in the magnetic ﬁeld of an electromagnetic system.

A winding on either the stationary or the rotating part of a machine whose sole purpose is the production of the main electromagnetic ﬁeld of the machine.

The sum of the ﬂuxes linking the turns forming the coil.

Devices that use electrochemical energy to produce a dc voltage.

A number of cycles completed in one second, the unit is Hertz.

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]]>A conductor providing either a common return path to the voltage source or a zero reference point, which makes it possible to obtain positive or negative voltages (with respect to ground) from the same power supply.

An iterative technique for solving a set of nonlinear equations (e.g., the power ﬂow equations), which uses the latest values 0f the variables in seeking improved values of the other variables.

The integral over any closed surface of the normal component of the electric ﬂux density is equal in a rationalized system to the electric charge Q_{0} within the surface.

The mean of (n) distances produced by taking the nth root of their product.

The equivalent radius of a multi-stranded conductor.

A conductor having grounding connections at intervals, which is suspended usually above but not necessarily over the line conductor to provide a degree of protection against lightning discharges.

Devices which use electromagnetic induction to produce electrical energy.

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]]>Horse Power is a measure of the work output of a motor (electrical or otherwise). The conversion from HP to watts is 1 HP = 746 Watts (Imperial Units).

The SI unit of frequency; equal to one cycle per second.

The SI unit of inductance is Henry.

A coil has an inductance of one henry when a current change of one ampere per second induces a counter emf of one volt.

A filter that passes all frequencies above a specified frequency with little or no attenuation but discriminates or rejects all lower frequencies.

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]]>A transformer characterized by no winding resistance, no leakage ﬂux, and a lossless and inﬁnitely permeable magnetic core.

A diagonal matrix whose elements in the principal diagonal are all equal to unity and all elements not in the principal diagonal are equal to zero.

An asynchronous AC machine that comprises a magnetic circuit interlinked with two electric circuits, rotating with respect to each other, and in which power is transferred from one circuit to another by electromagnetic induction.

** **These are the measurement units used in the United States. Typical units are feet, inches, pounds, and horsepower.

An active element (two terminal) which maintains specified voltage and is independent of rest of the circuit elements, with zero internal resistance.

Materials that have no free electrons and thus prevent the passage of electric current.

An active element (two terminal) which keeps the value of the current constant in spite of voltage across the terminals, with infinite internal resistance.

Impedance is the combined resistance in the flow of current because of resistive and reactive elements in the circuit.

Inductance is the property of an element to store energy in a magnetic field.

Opposition to the flow of an alternating current by the inductance of a circuit; equal to 2πfL and measured in ohms.

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]]>The SI unit of work.

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