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Commonly used terms in the Electrical industry.
International Electro-technical Commission
the international standards and conformity assessment body for all fields of electrotechnology.
See
IEC
Kerr effect
the quadratic electro-optic effect, particularly in the case for gases and liquids.
leakage reactance
the amount of inductive reactance associated with leakage flux. The leakage flux is the flux which traverses in paths farther from the designated paths such as the magnetic core in transformers and the air gap in electric machines and constitutes the non-useful flux. The electric circuit symbol of leakage reactance is Xl . It is a function of the leakage inductance and the frequency of operation. Higher values of leakage reactance affect the regulation and efficiency of the system. Xl is expressed in ohms.
light loss factor (LLF)
the ratio of the illumination when it reaches its lowest level at the task just before corrective action is taken, to the initial level if none of the contributing loss factors were considered.
lighting effectiveness factor (LEF)
the ratio of equivalent sphere illumination to ordinary measured or calculated illumination.
line outage distribution factor
a ratio used in contingency analysis. Given two parallel lines in a power system called x and y, assume that line y is removed from service. The line outage distribution factor of line x for the outage of line y is the ratio of the change in power flow on line x to the flow on line y before the outage.
line-connected reactor
See
shunt reactor
loss factor
the product of the dielectric constant and the power factor.
magnetic actuator
any device using a magnetic field to apply a force.
magnetic induction
the flux density within a magnetic material when driven by an external applied field or by its self demagnetizing field, which is the vector sum of the applied field and the intrinsic induction.
magnetic polarization vector
an auxiliary vector in electromagnetics that accounts for the presence of atomic circulating currents in a material. Macroscopically, the magnetic polarization vector is equal to the average number of magnetic dipole moments per unit volume.
magnetic vector potential
an auxiliary field used to simplify electromagnetic computations. This field satisfies a wave equation, the curl of this field is related to the magnetic field intensity vector field, and the divergence of this field is specified by some gage which is to be specified in each problem.
magnetostriction
a change in the length of a ferromagnetic material as the flux changes under the influence of an applied magnetic field, or resulting from domain formation after cooling from above Curie temperature. In an AC device, the steel in the core expands and contracts twice each cycle, creating audible noise (e.g., transformer hum).
magnetostrictive smart material
one of a class of materials with self-adaptively modifiable elastic properties in response to a magnetic field applied in proportion to sensed stress-strain information.
male connector
a connector presenting pins to be inserted into a corresponding female connector that presents receptacles.
motor circuit protector (MCP)
a listed combination motor controller containing an adjustable instantaneous-trip circuit breaker and coordinated motor overload protection. MCPs can provide short-circuit and bolted ground-fault protection via the circuit breaker magnetic element, overload protection via the overload device, motor control, and disconnecting means all in one assembly.
mutual inductance
the property that exists between two current-carrying conductors when the magnetic lines of force from one link with those from another.
National Electrical Code (NEC)
a standard for electrical construction, published by the National Fire Protection Association (NFPA 70-1). The National Electrical Code is often adopted by local jurisdictions and used by their electrical inspectors.
National Electrical Manufacturers Association (NEMA)
an electrical trade association that establishes standards for electrical equipment. In the case of electric motors, NEMA establishes standard frame sizes, starting torque, starting current, and other quantities for a given horsepower machine.
National Fire Protection Association (NFPA)
sponsor and publisher of the National Electrical Code and other safety standards.